MXPA00009038A - Optical translation measurement. - Google Patents
Optical translation measurement.Info
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- MXPA00009038A MXPA00009038A MXPA00009038A MXPA00009038A MXPA00009038A MX PA00009038 A MXPA00009038 A MX PA00009038A MX PA00009038 A MXPA00009038 A MX PA00009038A MX PA00009038 A MXPA00009038 A MX PA00009038A MX PA00009038 A MXPA00009038 A MX PA00009038A
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- illumination
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- G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
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Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Human Computer Interaction (AREA)
- Electromagnetism (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Power Engineering (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Optical Transform (AREA)
- Position Input By Displaying (AREA)
- Optical Radar Systems And Details Thereof (AREA)
- Investigating Or Analysing Materials By Optical Means (AREA)
Abstract
A method for determining the relative motion of a surface with respect to a measurement device comprising: illuminating the surface with incident illumination; detecting illumination reflected from the surface to form at least one detected signal; and determining the amount of relative motion parallel to the surface from said at least one detected signal, characterized in that said determining includes correcting for the effects of relative motion perpendicular to the surface.
Description
OPTICAL TRANSFER MEASUREMENT
Field of the Invention The present invention relates to the field of speed measurement and translation and more particularly to methods and an apparatus for the optical measurement of speed and translation, which is not contact.
BACKGROUND OF THE INVENTION There are several optical methods for measuring the relative speed and / or movement of an object with respect to a measurement system. The types of objects and the kinds of movements over which they operate characterize each of the methods and the apparatus. The type of measurable objects can be broadly divided into several groups, including: • A specially designed object, for example, a scale. • A reflection surface, for example, a mirror. • A small particle (or small particles) for example, precursor particles or bubbles suspended in liquids. • An optically contrasting surface, for example, a dotted line or pattern. • An object that diffuses optically, for example, a sheet of white paper.
The types of measurable movements can be broadly divided into several groups, including: • Axial movement to or from the measuring device. • The transverse (or tangential) movement, where the space between the measuring apparatus and the object is essentially constant.
• The rotation movement, where the orientation of the object with respect to the measuring device is changing. It is also useful to classify measuring devices according to the number of measurement instructions that can be obtained simultaneously (in one, two or three dimensions) and the number of critical components (light sources, light detectors, lenses, etc.). ). It should be noted that a specific method may be related to more than one group of schemes in the previous classification. A number of systems capable of measuring without contacting the transverse speed and / or movement of objects using optical means have been reported. These methods may include the methods of Point Velocimetry (Speckle) and Doppler Laser Velocimetry methods. Other methods of interest for the understanding of the present invention are the methods of Image Velocimetry, Homodine / heterodine Doppler Velocimetry or Interferometry methods and Optical Coherence Tomography (OCT). Speckle Velocimetry methods are generally based on the following principles of operation:. A coherent light source illuminates the object whose movement needs to be measured. • The illuminated object (usually an opaque surface) consists of multiple scattering elements, each with its own coefficient of reflection and phase change in relation to other scattering elements. • The individual coefficients of reflection and phase changes are substantially random. At a particular point in space, the amplitude of the electric field of reflection from the object is the sum of the vector of the reflections from the illuminated scattering elements, with an additional phase component that depends on the distance between the point and each of the elements.
• The intensity of the light at the point will be high when contributions are added generally in phase, and low when aggregate contributions are added out of phase (for example, a subtraction).
• On a flat surface (opposite a point) an image of random light and dark areas is formed since the relative retardation of the phase of the points of the source depends on the location in the plane. This image is called a "speckle image", composed of points of brightness and darkness ("speckles"). • The typical size of the "speckle" (the typical average or average distance for a significant change in intensity) depends mainly on the wavelength of light in the distance between the object and the speckle plane of the image and the size of the area illuminated
• If the object moves relative to the plane in which the speckie image is observed, the speckie image will also move, essentially at the same transverse velocity. (The speckie image will also change, since some dispersants leave the area illuminated and others enter it). • The speckie image passes through a structure comprising a series of clear and opaque or reflective lines, just as the speckie image is modulated. This structure is usually a pure transmission grid, and ideally, it is placed near the detector to obtain maximum contrast.
• The detector translates the intensity of the light that passes through the structure, to an electrical signal, which is a function of the intensity (usually a linear function). • When the object moves with respect to the measuring device, the speckie image is modulated by the structure so that the intensity of the light reaching the detector is periodic. • The period is proportional to the separation of the line from the structure and inversely proportional to the relative speed. . By means of the correct analysis of the signal, the oscillation frequency can be found, which indicates the relative speed between the object and the measuring device. The determination of high accuracy frequency for these methods requires a large detector, while the high contrast in the signal requires a small detector. A paper by Popov and Veselov, entitled "Tangential Measurements of the Velocity of Fuzzy Objects Using the Dynamically Modulated Spleckle" (SPIE 0-8194-2264-9 / 96), gives a mathematical analysis of the accuracy of speckie velocimetry. US Patent 3,432,237 issued to Flower and associates describes a speckie velocity measurement system in which either the transmission pattern or the minute aperture is used to modulate the speckie image. When the minute aperture is used, the signal represents the passage of individual spectra through the minute aperture. US Pat. No. 3,737,233 issued to Blau et al. Uses two detectors in an attempt to solve the problem of directional ambiguity, which exists in many speckie velocimetric measurements. It describes a system that has two detectors, each one associated with a transmission grid. One of the grids is stationary with respect to its detector and the other one moves with respect to its detector. Based on a comparison of the signals generated by the two detectors, the sign and magnitude of the speed can be determined. U.S. Patent 3,856,403 issued to Maughmer and associates also attempts to avoid directional ambiguity by providing a moving grid. This provides an inclination for speed measurement by moving the grid at a speed higher than the maximum relative speed expected between the surface and the speedometer. The change in frequency reduces the effect of changes in the total intensity of light (DC) and low frequency components), thereby increasing the range and dynamic accuracy of the measurement. In the PCT Patent publication WO 86/06845 issued to Gardner and associates, a system designed to reduce the amplitude of the CD and the components of the low frequency signal of the detector signal is described, subtracting a reference sample from the light of the source coming from the speckie detector signal. The reference signal is proportional to the total intensity of the detector light, reducing or eliminating the influence of variations in the total intensity of the measurement. This reference signal is described as being generated, using a lightning separator between the measured surface and the main detector using the grid that is used for the detection of the speckie, also as a lightning separator (using a transmitted light for the detector main and reflected light for the reference detector) or using a second set of detectors to provide a reference signal. In a modality described in this publication, the two signals have the same CD component and opposite AC components so that the difference signal not only removes substantially the CD components (and near DC), but also substantially increases the AC components. In the North American Patent 4,794,384 granted to Jackson, a system is described in which the speckie pattern reflected from a measured surface is formed in a 2D CCD distribution. The translation of the surface in 2 dimensions is found using the electronic correlation between successive images. It also describes an application of your device to use it as an "optical mouse without attenuator". The velocimetry methods of the image measure the speed of an image in the entire plane of the image. The image must include contrasting elements. A line pattern (very similar to a grid) modulates the image space, and the light sensitive detector is measuring the intensity of the light passing through the pattern. In this way, a speed to frequency ratio is formed between the speed of the image and the AC component of the detector. Normally, the line pattern moves with respect to the detector, so that the frequency is skewed. In this way, the address ambiguity is solved and the dynamic range expanded. A paper by Li and Aruga, entitled "Perception of Speed by Illumination with a Laser Beam Pattern" (Applied Optics, 32, page 2320, 1993), describes the velocimetry of the image where the object itself is illuminated by a periodic line structure (instead of passing your image through that pattern). The pattern of lines is obtained by passing an expanded laser beam through the periodic transmission grid (or line structure). According to a suggested method, the object still needs to have contrasting characteristics.
There are a number of differences between Image Velocimetry (IV) and Speckie Velocimetry (SV). In particular, in the SV the random image is forced by the coherent light source, while in the IV an image with its own contrasting elements has already been assumed. In addition, in the SV the tangential velocity of the object is measured, while in the IV the angular velocity is measured (the speed of the image in the plane of the image is proportional to the angular velocity of the line of sight). In North American Patent 3,51 1, 150 granted to Whitney and associates, a two-dimensional translation of line patterns creates a frequency change. A line pattern of a single circular line in rotation creates all the necessary translation line patterns in specific elongated openings in a circular concealer. The frequency change is measured online using an additional detector that measures a fixed image. The line pattern is divided into two regions, each adapted to the measurement of a different speed range. The system basically aims to compensate the image of the movement in order to reduce the distortion of the image in aerial photography, also, it is useful for the heads that house the missiles. US Patent 2,772,479 issued to Doyle describes an image velocity system with frequency compensation derived from a grid in a rotating band.
Doppler Laser Speedometers generally use two laser beams formed by the separation of a single source, which interferes with a known position. A light scattering object that passes through the interference space scatters the light from both rays to the detector. The detector signal includes an oscillating element that often depends on the speed of the object. The phenomenon can be explained in two ways. An explanation is based on an interference pattern that is formed between the two rays. In this way, in that space, the intensity changes periodically between planes of brightness and darkness. An object that passes through the planes scatters the light in proportion to the intensity of the light. Therefore, the detected light is modulated with frequency proportional to the velocity component of the object perpendicular to the interference planes. A second explanation considers that an object that passes through the space in which both rays of light exist, scatters the light of both. Each reflection is changed in frequency due to the Doppler effect. However, the Doppler shift of the two rays is different due to the different angles of the incident rays. The two reflections interfere in the detector, so that the pulse signal is established, with a frequency equal to the difference in the Doppler shift. This difference, therefore, is proportional to the velocity component of the object perpendicular to the interference planes.
It is common to add a frequency offset to one of the rays, so that the zero velocity of the object will result in a non-zero frequency measurement. This solves the ambiguity of the direction of movement (caused by the lack of ability to differentiate between positive and negative frequencies) and significantly increases the dynamic range (sensitivity of low speeds) producing signals far from the CD component. Frequency compensation also has other advantages related to identifying and blocking the signal. U.S. Patent 5,587,785 issued to Kato and associates, describes said system. Frequency compensation is implemented by providing a fast linear frequency sweep to the source beam before it is separated. The separation method is such that there is a delay between the resulting rays. Because the frequency is swept, the delay results in a fixed frequency difference between the rays. Multiple beams with different frequency compensations can be extracted by additional separation of the source with additional delays. So, each of these delays is used to measure a different range of dynamic velocity. A paper by Matsubara and associates, titled "Simultaneous Measurement of the Speed and Displacement of a Rough Surface in Motion by a Doppler Laser Speedometer" (Applied Optics, 36, page 4516, 1997), presents a mathematical analysis and results of the simulation of the measurement of the transverse velocity of a rough surface using an LDV. It is suggested that the displacement along the axial axis can be calculated from measurements made simultaneously by two detectors at different distances from the surface. In the measurements Homodina / Heterodina Doppler, a source of coherent light is separated in two rays. A beam (a "main" beam) illuminates the object whose velocity is to be measured. The other ray (a "reference" ray) is reflected from a reference element, usually a mirror, which is part of the measurement system. The light reflected from the object and from the reference element is combined (usually by the same ray separator) and directed to the light-sensitive detector. The frequency of light reflected from the object is changed due to the Doppler effect, in proportion to the velocity component of the object along the bisector between the main beam and the reflected beam. In this way, if the reflected beam coincides with the main beam, axial movement is detected. The detector is sensitive to the intensity of light, for example, to the square of the electric field. If the electric field received from the reference path in the detector is E0 (t) = E0 cos (? Or t + f0) and the electric field received from the object in the detector is Ei (t) = E-. cos (?? t + fi), then the detector output signal is proportional to (E0 + E-.) 2 = E0 2 + E0 Ei + E- \ 2.
The first term on the right side of the equation is averaged by the time / constant detector and results in a CD component. The intensity of the reference beam is generally much stronger than the intensity of the light reaching the detector from the object, so that the last term can generally be omitted. Developing the middle term:
E0 Ei = E0 Ei cos (? 0 t + f0) cos (? 1 t + f1) = 1/2 Eo E-, [cos ((? 0 +? 1) + t f0 + f 1) + cos (( ? 0 -? 1) + f0 + f1) From this equation, it is evident that E0 Ei includes two oscillating terms. One of these oscillating terms is approximately twice the optical frequency and is averaged to zero by the constant-time of the detector. The second term oscillates with the frequency? 0 -? 1, for example, with the same frequency as the frequency change due to the Doppler effect. In this way, the output signal of the detector contains an oscillating component with the frequency indicating the measured speed. It is common to add frequency compensation to the reference beam. When said frequency inclination is added, this is called Heterodyne Detection. U.S. Patent 5,588,437 issued to Byrne et al., Describes a system in which a laser light source illuminates a biological tissue. The light reflected from the surface of the skin serves as a reference beam for the homodyne detection of light that is reflected from the blood that flows beyond the skin. In this way, the skin acts as a diffused separator of the ray close to the measured object. An advantage of using the skin as the ray separator is that the general movement of the body does not affect the measurement. Only the relative speed between blood and skin is measured. This distribution uses two pairs of detectors. Each pair of detectors is connected to produce a difference signal. This serves to reduce the CD and low frequency components that interfere with the measurement. A beam scanning system makes it possible to trace the two-dimensional flow of blood. In Optical Coherence Tomography (OCT), a low coherence light source ("white light") is directed and focused on the volume that is to be analyzed. A portion of the source light is separated to a reference path using a lightning separator. The optical length of the reference path is controllable. The light reflected from the source and the light from the reference path are recombined using a lightning separator (conveniently the same used to separate the light from the source). A detector sensitive to light measures the intensity of the recombined light. The coherence length of the source is very short, so that only light reflected from a small volume centered on the same optical distance from the source as the reference light interferes coherently with the reference light. Other reflections from the volume of the sample are not coherent with the reference light. The length of the reference path is changed linearly (usually periodically, in the form of a wave with a serrated shape). This allows the analysis of the material with depth. In addition, a Doppler frequency change is introduced to the measurement, allowing a clear detection of the volume return that interferes coherently with a high dynamic range. In a conventional OCT, a profile of the depth of the magnitude of the reflection is acquired, providing a contrast image of the volume analyzed. In another more advanced OCT, the frequency changes from the nominal Doppler frequency are detected and are related to the magnitude and direction of the relative velocity between the analyzed volume (in a coherence range) and the measurement system. U.S. Patent 5,459,570 issued to Swanson and associates, describes a basic OCT system and numerous applications thereof. A letter from Izatt and associates, entitled "Image Processing of a Bidirectional Color Doppler Flow of Picolitre Blood Volumes Using an Optical Coherence Tomography" (Optics Letters, 22, page 1439, 1997), describes an OCT based on optical fiber with a capacity for the mapping of speed. The fiber optic ray separator is used to separate the trajectories of the light before reflection from the sample in the main path and from the mirror in the reference path and combine the reflections in the opposite direction. A paper by Suhara and associates, entitled "Integrated Optical Monolithic Displacement / Position Sensor Using QW-DFB Wave and Laser Guides" (IEEE Photon, Technol.Lett.7, page 1 195, 1995), describes a monolithic interferometer fully integrated, with ability to measure the variations in distance in a reflecting mirror from the measuring device. The apparatus uses a diffraction reflective element (Bragg reflector with distributed focus) in the path of the light from the source as a combined beam splitter and local oscillator reflector. The detection of the direction is achieved by means of a distribution that introduces a static phase change between the signals of the detector. Each of the aforementioned Patents, Patent publications, and references are incorporated herein by reference.
Summary of the Invention. The present invention, in its broadest form, provides an Optical Translation Measurement (OTM) method, and an apparatus capable of providing information indicating the quantity and optionally the direction of relative translation between the apparatus and an adjacent object. Preferably, the object is at least partly rough and is closely spaced from the apparatus. As used in the present invention, the terms "rough" or "diffuse" mean optically irregular or non-uniform. In particular, the object may have a diffuse opaque or semitransparent surface such as paper. This description deals mainly with the determination of the translation or speed of said diffuse surfaces. However, it should be understood that many of the methods of the present invention may also be applicable for the determination of the translation of other types of objects such as small dispersion particles, possibly suspended in a liquid. The translation of the object means that its rotation in space can be omitted as explained below. In a first aspect of some of the preferred embodiments thereof, the present invention provides the heterodyne or homodine detection different from Doppler, image signals that are not spectra derived from changes in the phase and / or the amplitude of the reflection from an optically irregular surface. In a second aspect of some preferred embodiments of the present invention, which can be applied to various motion or velocity detection methods, the present invention provides a system in which a reflector, which reflects part of the incident light, is placed near the surface whose movement is going to be measured. The reflector provides a signal from the local oscillator that is inherently coherent with the light that is reflected from the surface. This aspect of the present invention is applicable to both Doppler and non-Doppler methods of motion detection. In a preferred embodiment of the present invention, the partial reflector is a grid and the illumination of the surface whose movement is measured passes through the grid. In a preferred embodiment of the present invention, the grid covers a portion of the measured surface and has a substantial amount of transmission. In this preferred embodiment of the present invention the reflections from the surface pass through the grid. A combination of reflection and partial transmission is often useful, especially in the preferred embodiments of the present invention which utilize the third aspect of the invention. In a third aspect of some preferred embodiments of the present invention, asymmetric transmission patterns are provided to assist in determining the direction of surface movement. In a fourth aspect of some preferred embodiments of the present invention, a phase change is introduced between at least part of the reflection from the partial reflector and at least part of the reflection from the surface. This phase change makes it possible to determine the direction of movement, increases the dynamic range and improves the signal-to-noise ratio.
This phase change may, in some preferred embodiments of the present invention, be dynamic, for example, of varying time. Said phase variations are conveniently performed by moving the reflector either perpendicular to the surface or parallel to the surface or a combination of both. Also, the movement can be from a pattern in the reflector, for example, the movement of a stable wave that acts as a grid in an Acoustic Surface Wave (SAW) component. In this aspect, the pattern on the reflector moves, and not the entire reflector. Alternatively, the phase change is introduced by periodically varying the optical path length between the reflector and the surface, for example, by inserting a piezoelectric material into the optical path. The phase change can also be a static phase change. Conveniently, this static phase change is introduced between the polarization components of one of the rays (or a part of the energy in the beam). The direction of movement is determined by a measurement of a corresponding phase change between the detected signals, and more particularly, by means of the measurement of the phase change sign, between the signals. In some preferred embodiments of the present invention, which incorporate this aspect thereof, a polarizer is used to polarize the illumination reflected from the surface. This is especially important when the surface is not preserving the polarization. A fifth aspect of some preferred embodiments of the present invention provides a motion detection based on the Doppler detection of a surface in a direction parallel to the surface. In this aspect of the present invention, a single beam may be incident at an angle to the surface, and may still be incident perpendicular to the surface. A sixth aspect of the preferred embodiments of the present invention provides simultaneous detection of two- and three-dimensional translation using a single illumination beam and a simple reflector to provide local reference beam oscillators. In a preferred embodiment of the present invention, the signal generated by a single detector is used to determine translation in two dimensions. In a seventh aspect of some preferred embodiment of the present invention, a spatial filter is provided, so that substantially only a single spatial frequency of the illumination reflected from the surface is detected by the detector. In some preferred embodiments of the present invention, which incorporate this aspect thereof, the spatial filter comprises lenses having a focal point and a minute aperture which is positioned at the focal point of the lenses. Preferably, the illumination of the surface is collimated, and the spatial filter filters the reflected illumination so that only radiation reflected from the surface substantially in a single direction is incident on the detector. In an eighth aspect of some preferred embodiments of the present invention, the spatial filter is performed by means of an "effective minute aperture". This effective aperture is achieved by focusing a local oscillator field, such as reflected or diffracted light from a grid in the detector. In this way, the amplification of the reflected field from the surface is achieved only at the focus of the local oscillator field. Preferred embodiments of the present invention, which utilize an effective minute opening, are easier to align, and have less severe tolerance requirements. This is especially true when the local oscillator is derived from the diffracted light from a grid in a non-zero order, since in the case of the placement of the aperture minuta depends on the wavelength. Thus, the stability requirement of the wavelength of the illumination source is more relaxed when an effective aperture is used instead of a physical one. An apparatus according to a preferred embodiment of the present invention includes a light source, a grid, a spatial filter, a photodetector, and the electronic components processing the signal. The light source provides at least partially coherent radiation, which is directed towards the surface so that part of the illumination is reflected, or is refracted from the grid towards the detector. An optical grid is placed between the surface and the light source, preferably near the surface. The light reflected from the surface, interferes with the light that is reflected or diffracted back from the grid. The detector signal includes an oscillating component, which is representative of the relative translation of the surface to the optical apparatus. The interference can be done with normal reflection from the grid, or with the diffracted light in any of the orders of the grid. More preferably, the light is filtered spatially before detection by means of the detector. Two dimensional translational measurements can be achieved, using two or more detectors illuminated by orthogonal reflection commands from the two-dimensional grid, or by using two separate gratings for two directions. A third dimension can be deduced by calculating the vector of the translations measured in different orders on the same axis, using different techniques of signal analysis in the same signal. The optional detection of the translation direction (as opposed to its absolute magnitude) is preferably achieved by modulating the position of the grid to provide a frequency compensation. Alternatively, a varying length of optical path between the grid and the surface introduces the frequency compensation. Alternatively, the phase change is introduced between the different polarization components to produce the direction dependent phase difference between the corresponding detected signals. Alternatively, the address can be determined by other means. A ninth aspect of some preferred embodiments of the present invention relates to alternative methods for determining the direction of movement. In the preferred embodiments of the present invention, which provide this aspect thereof, the mechanical movement of an optical part is used to determine the direction of movement. In some preferred embodiments of the present invention, two detectors are provided. Movement in one direction causes illumination of one of the detectors by reflected or refracted light from the grid. The movement in the other direction causes the illumination of the other detector. A tenth aspect of some preferred embodiments of the present invention relates to a method that utilizes the Doppler shift of light reflected from the surface. A local oscillator change is provided by the light reflected from the reflecting surface located at an angle of the movement surface. The light reflected from the reflection surface and the light reflected from the movement surface, interfere in a detector to produce a signal with a frequency proportional to the relative speed of the two surfaces. This method has the advantage that grid is not required and that the alignment and stability of the illumination frequency are not substantially critical.
The methods and apparatus of the present invention are applicable to a wide range of applications that require translation measurement. One such application is an "optical mouse without attenuators", which can effectively control a movement of the cursor by moving the mouse across the width of the optically diffuse surface such as a paper or a desktop computer. Another example application of the present invention is for a "point of contact", which moves the movement of the finger over an opening of the apparatus to control a cursor or any other entity controlled by translation or speed. According to a preferred embodiment of the present invention, the measuring apparatus comprises a light source to at least partially provide the coherent radiation. The radiation source is directed towards an optical grid of one dimension or two dimensions, which is preferably close to the surface. Reflections of light from the grid and from the surface interfere, and light is collected through a spatial filter (for example, a lens and a minute aperture at its focal point on a light detector). The resulting interference signal contains the pulsations related to the relative translation of the optical apparatus and the surface. In the preferred embodiments of the present invention, the translation is measured directly by counting the zero crossings of the oscillating signal of the detector, and thus is not subject to errors caused by changes in speed. For the preferred embodiments of the present invention, the instantaneously instantaneous position determination was established. In many applications, the direction of translation is required, as well as its magnitude. In a preferred embodiment of the present invention, this is accomplished by incorporating a dynamic phase change apparatus (such as a piezoelectric transducer), which creates an asymmetric pattern of phase change (generally a toothed waveform) between the reflected light from the grid and from the surface, making it possible to extract simple information from the address. In another preferred embodiment of the present invention, a static phase change is introduced between the different polarization components of a beam and the direction is determined using a resulting phase difference between the corresponding detected signals. Alternatively, direction detection is achieved by using, preferably, an asymmetric transmission pattern specially designed for the grid / matrix (such as a toothed transmission or other form that is described herein), with appropriate processing / manipulation of the signal on the output signal of the detector. An asymmetric transmission pattern provides the means for detecting the direction of movement in other velocimetry methods as well, such as speckie velocimetry. Alternatively, direction detection is provided using a mechanically movable element that changes the reflected illumination between the detectors, depending on the direction of movement. The coherent detection of the free translation of the speckie can be determined by collecting the scattered light (the light that passes through the grid and is reflected from the moving surface) as a spatial filter, such as a combination of focus lenses and a Minute aperture (or a single mode optical fiber) in the focal position of the lens. The light reflected from the surface is combined with a local oscillator light field (which is preferably light reflected or diffracted by the grid itself) whose field is preferably a part of the light beam that also passes through the spatial filter. Interference with the strong local oscillator light source provides the amplification of the signal detected by an intensity sensitive photodetector. This method of coherent detection is called homodyne detection. The spatial filter can be operated to spatially integrate the reflected light from the surface to a detector, so that the relative phases of the reflections from different locations on the surface, are essentially not changed when the surface moves with respect to the detector. In addition, the phase of a separator on the surface (such as and is measured in the detector) depends linearly on the translation of the surface. Also, the spatial filter is ideally used to filter the local oscillator so that the detector will be integrated over no more than a single interfering edge resulting from interference between the local oscillator and the reflected light from the surface. In an extreme case, the incident light on the surface is perfectly collimated (for example, it is a plane wave). Accordingly, the spatial filter may simply be a lens with a minute aperture placed at its focal point. Any translation of the surface does not change the relative phases of the light integrated by the spatial filter. The local oscillator beam formed by reflection or diffraction of the reflector or grid, are also collimated perfectly, so that they can pass through the spatial filter (the spatial filter is placed so that the source falls or is inside the aperture minuta ). This forces a single interference edge on the detector. No limitations are imposed (with respect to spatial filtering) in the separation between the reflector and the surface. In another extreme case, the space between the surface and the reflector is negligible. This allows the use of an incident ray substantially not collimated while still maintaining the relative phases of the reflections from the surface, independently of its translation and also maintains the same focus point for the local oscillator and the reflection of the surface. Optionally, a spatial filter with lenses and a minute aperture placed in the plane of the reflection image of the source can be implemented as a local oscillator.
In order to have (as far as possible) a single speckie integrated by the detector, the size of the aperture must not exceed the size of approximately a single speckie formed by the reflection from the surface (for this reason the measurement is you can determine "speckie-free"). Therefore, if the detector itself is small enough, it can serve as an integral part of the spatial filter and the minute aperture is not required. The preferred conditions, of the relative unchanged phases and the single interference edge with the local oscillator in the detector, can be met in a multitude of substantially optical equivalent means. In particular, the requirement can be established using a single converging lens placed before or after reflection of the light from the local oscillator reflector. Alternatively, the lens and the reflector can be combined in a single optical apparatus. Also a collimating lens can be placed between the beam separator and the surface (for example, only light coming from and towards the surface passes through this lens). Spatial filtering that is not ideal (such as when the minute aperture is too large, or when it is out of focus for either the surface reflections or the local oscillator or both) results in deterioration of the signal and possibly addition from noise to measurement. The level of deterioration depends on the amount and type of deviation from the ideal.
In a preferred method according to the present invention, both the illumination of the surface and the reference light are provided using a single optical element, preferably a grid. The light of the surface and reference share a single optical path through most or all optical elements of the device. In addition, the spatial amplitude and / or modulation of the phase can be imposed on the light reaching the surface by the grid to provide additional means for measuring the translation of the surface. In particular, the tangential translation can be measured even for the specular reflection from the grid, where there is no Doppler shift, and the identification of the direction of movement can also be achieved. In a eleventh aspect of some preferred embodiments of the present invention, an integrated motion detection system provides signals that are indicative of the amplitude, and optionally the direction of movement. In a preferred embodiment of the present invention, at least some of the components of the motion detection system are mounted on an optical substrate. These components preferably include at least one radiation source and an optical element, such as a grid, a reflector or a partial reflector, which generate a local oscillator field from the radiation. It is also mounted on the optical substrate, a detector that is illuminated by the local oscillator field and the reflected radiation from the surface whose relative movement is measured. In this embodiment of the present invention, the lengths of the path of the local oscillator field and the field reflected from the surface whose movement is measured, is such that the two fields are coherent in the detector. In a twelfth aspect of some preferred embodiments of the present invention, the exact measurement of the movement parallel to the surface is obtained by compensating for the influence of the movement perpendicular to the surface and compensating for the influence of the inclination of the measurement. This aspect of the present invention is especially useful for use in a computer control apparatus such as a computer mouse. Therefore, according to a preferred embodiment of the present invention, there is provided a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Surface illumination with incident illumination; Detecting the illumination reflected from the surface to form at least one detected signal; and determining the relative amount of movement parallel to the surface from said at least one detected signal, characterized in that said determination includes correction for effects of relative movement perpendicular to the surface.
Preferably, said at least one signal comprises at least two signals, at least one first signal which is affected by the relative movement parallel to the surface and the relative movement perpendicular to the surface and at least one second signal which it is affected at least by the movement perpendicular to the surface, and the determination comprises, the determination of the amount of relative movement parallel to the surface of the two signals. Preferably, the determination comprises: determining a first amount of relative movement from at least one of said two signals, said first amount of relative movement including a component parallel to the surface and a component perpendicular to the surface; The determination of a second amount of relative movement from at least one of said two signals, said second amount of relative movement including a component perpendicular to the surface; and The determination of the relative amount of movement parallel to the surface in response to the first and second determined amounts of relative motion. Preferably, the second amount of relative movement does not include a component parallel to the surface. Preferably, the second relative movement amount includes a component parallel to the surface.
In a preferred embodiment of the present invention, the relative movement perpendicular to the surface is determined based on a Doppler shift of the reflected illumination. In a preferred embodiment of the present invention, the determination comprises determining the amount of relative movement parallel to the surface directly from the two signals without determining the amount of relative movement perpendicular to the surface. Preferably, at least one second signal is determined substantially by relative movement perpendicular to the surface. In a preferred embodiment of the present invention, at least one second signal is a signal based on a Doppler shift. Preferably, the at least one second signal is in response to relative movement parallel to the surface. In a preferred embodiment of the present invention, the method includes determining the amount of relative movement perpendicular to the surface. In a preferred embodiment of the present invention, the determination of the relative amount of movement parallel to the surface includes determination of the relative amount of movement along two non-collinear directions. In a preferred embodiment of the present invention, the illumination is perpendicularly incident on the surface.
In a preferred embodiment of the present invention, detection comprises coherent detection. Preferably, the method includes reflection or diffraction of a portion of the illumination from an object, which is part of the measuring apparatus, to act as a local oscillator. Preferably, the object is a partially reflective object, through which the illumination passes either incident or reflected. Preferably, both incident and reflected illumination pass through the object. In a preferred embodiment of the present invention, the object is adjacent to the surface. In a preferred embodiment of the present invention, the surface is in a field close to the object. Alternatively, the surface is outside the near field of the grid. In a preferred embodiment of the present invention, the object is a grid. Preferably, the grid essentially produces only a single order of transmitted illumination which illuminates the surface. Preferably, the illumination is at least partially coherent and the object is placed within the coherence length of the illumination from the surface. In a preferred embodiment of the present invention, the illumination of the local oscillator and the reflected illumination are incidents in at least one detector to produce said signals and the local illumination of the oscillator and the reflected illumination are at least partially coherent in the detector. Furthermore, according to a preferred embodiment of the present invention, there is provided an apparatus for measuring the relative movement between the apparatus and a surface, which comprises: A source of illumination, which transmits the illumination to illuminate the surface; A first detector which receives the illumination from the source, reflected from the surface; An object which reflects a portion of the illumination to said detector, so that the detector generates a first signal based on a coherent detection of the illumination reflected from the surface with the illumination reflected by the object as a local oscillator; A second detector which receives the illumination from the source without receiving the illumination reflected from the surface and generates a second signal in response to it; A signal corrector which adjusts the first signal for changes in illumination intensity, based on the second signal; and A motion calculator that calculates relative motion in response to the signal from the signal corrector.
Preferably, the illumination of the source received by the second detector is the illumination reflected from or diffracted by the object. Preferably, the signal corrector corrects the first signal by a constant term based on the second signal. Preferably, the signal corrector includes a difference amplifier which receives the first signal and subtracts the second signal from the. same to produce a first adjusted signal. Preferably, the signal corrector includes a standard signal which receives the first adjusted signal and normalizes it with respect to the second signal. In a preferred embodiment of the present invention, the apparatus includes: A third detector that receives illumination reflected from the surface, without receiving substantial illumination from the object or source and produces a third signal in response thereto; y The signal corrector corrects the adjusted signal based on the third signal. Further provided, according to a preferred embodiment of the present invention, is an apparatus for measuring the relative movement between the apparatus and a surface which comprises: A source of illumination, which transmits illumination to illuminate the surface;
A first detector which receives the illumination from the source, reflected from the surface; An object which reflects a portion of the illumination of the first detector, so that the detector generates a first signal based on the coherent detection of the illumination reflected from the surface with the illumination reflected by the object as a local oscillator; A second detector which receives the illumination from the source without receiving the illumination reflected from the surface and generates a second signal in response to it; A signal corrector which reduces the first signal by an amount proportional to the second signal; and A motion calculator that calculates relative motion in response to the signal from the signal corrector. Preferably, the illumination of the source received by the second detector is the illumination reflected from or diffracted by the object. In a preferred embodiment of the present invention, the signal corrector includes a normalizer that adjusts the first signal by changes in illumination intensity, based on the second signal. In a preferred embodiment of the present invention, the apparatus includes:
A third detector that receives the illumination reflected from the surface without receiving substantial illumination from the object or from the source and produces a third signal in response to it; y The signal corrector corrects the adjusted signal based on the third signal. Additionally, according to a preferred embodiment of the present invention, there is provided an apparatus for measuring the relative movement between the apparatus and a surface, which comprises: A source of illumination, which transmits illumination to illuminate the surface; A first detector which receives illumination from the source reflected from the surface; An object which reflects a portion of the illumination to said first detector, so that the detector generates a first signal based on the coherent detection of the illumination reflected from the surface with the illumination reflected by the object as a local oscillator; A second detector that receives illumination reflected from the surface without receiving substantial illumination from the object, or from the source and produces a second signal in response to it. A signal corrector that reduces the first signal by an amount proportional to the second signal; A motion calculator that calculates the relative movement in response to the signal from the signal corrector.
In a preferred embodiment of the present invention, the object is partially transmitting, and the object is placed between the illumination source and the surface, so that illumination of the surface passes through the object. In a preferred embodiment of the present invention, the illumination has a coherence length, and the object and the surface as they are located within said length of coherence. In a preferred embodiment of the present invention, the object is a grid. Preferably, the grid essentially produces only a simple order of transmitted illumination which illuminates the surface. Preferably, the surface is within the near field of the grid. Alternatively, the surface is outside the near field of the grid. In a preferred embodiment of the present invention, the illumination reflected from the surface and the illumination reflected by the object are at least partially coherent in the first detector. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of the surface with respect to a measuring apparatus, which comprises: Surface illumination, with incident illumination so that the lighting is reflected from the portions of the surface;
The coherent detection of the illumination reflected from the surface using the illumination derived from said incident illumination that was not reflected by the surface as a local oscillator, to form at least two signals; The determination of the relative motion magnitude of the surface from at least one of the two signals; The variation of the phase of at least part of the local illumination of the oscillator with respect to at least part of the illumination reflected by the surface; and The determination of the direction of relative motion parallel to the surface, based on a characteristic of the signals caused by said varied relative phase. Preferably, the illumination of the local oscillator is generated by the reflection or refraction of the incident illumination from an object that is a part of the measuring apparatus.
Preferably, the object is adjacent to the surface.
Preferably, the illumination has a coherence length and the object and the surface are located within said coherence length. Preferably, the object is a grid. Preferably, the grid essentially produces only a simple order of transmitted illumination that illuminates the surface.
Preferably, the surface is placed within the near field of the grid. Alternatively, the surface is positioned outside the near field of the grid.
In a preferred embodiment of the present invention, the variation of the phase comprises the introduction of a static phase change and the determination of the direction of relative movement, comprises the determination of the direction of relative movement, based on a characteristic of the signal caused by said static phase change. In a preferred embodiment of the present invention, the method includes: The division of the illumination that is reflected from the surface in a first illumination having a first phase and a second illumination having a second phase. Preferably, the first illumination and the second illumination have different polarizations. Preferably, the division comprises passing the incident illumination on the surface through a birefringent material. Alternatively or additionally, the division comprises passing the illumination reflected from the surface through a birefringent material. Preferably, the method includes placing the birefringent material between the object and the surface. In a preferred embodiment of the present invention, placement of the birefringent material between the object and the surface is operative to cause the detected illumination to pass through the birefringent material twice. In a preferred embodiment of the present invention, the method includes determining the magnitude and direction of translation using two detectors, which produce different detected signals dependent on the direction of translation. Preferably, the determination of the direction of the translation comprises the determination of the direction from the sign of the phase difference between the different signals detected. Preferably, the method includes linear polarization illumination reflected from the surface. It further provides, in accordance with a preferred embodiment of the present invention, an apparatus for determining the translation of a surface in relation to the apparatus, which comprises: An optical block, A detector, which produces a signal in response to a light shock in it, attached to the optical block; and A source of illumination that produces illumination, a portion passing through the block is reflected by the surface, and strikes the detector after passing through the optical block; and A circuit system that records the magnitude of translation parallel to the surface in response to the signal. Preferably, the apparatus includes an object in or on the surface of the block which reflects or diffracts a part of the illumination to the detector without said part colliding with the surface, said part acting as a local oscillator for the synchronous detection of the reflected illumination by the detector.
Further provided, in accordance with a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface with the incident radiation so that the illumination is reflected from a portion of the surface; The detection of at least a first part of the illumination reflected from the surface to form a first detected signal; The detection of at least a second part of the illumination reflected from the surface to form a second detected signal; and The determination of the relative movement amount based on the Doppler shift of the reflected radiation, wherein the first and second signals are in quadrature phase and the detection comprises the detection of the quadrature. Preferably, the method includes detecting the direction of relative movement in response to said first and second signals. Preferably, the method includes determining the relative movement in two parallel non-colinear directions to the surface. Preferably, the method includes determining the relative movement in a direction perpendicular to the surface.
Preferably, the method includes determining the relative movement comprising the zero crossing count of at least one of said first and second signals. Preferably, the detection comprises coherent detection. Further provided, in accordance with a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: The illumination of the surface with incident illumination so that the illumination it is reflected from portions of the surface; The coherent detection of the illumination reflected from the surface using a detector to form a signal; The use of the illumination derived from said incident illumination that was not reflected by the surface as a local oscillator, for said coherent detection; and The determination of the magnitude of the relative movement of the surface from the signal; Characterized because the local oscillator is focused on a small area on the detector, so that essentially only a simple spatial frequency of the reflected illumination forms an interference field with said local oscillator in the detector.
Further provided, according to a preferred embodiment of the present invention, is an apparatus for determining the relative movement of a surface with respect to the apparatus, which comprises: A cover having an opening formed therein; A detector inside the cover that produces a signal used to determine the relative movement; A laser illumination source of a certain wavelength, inside the cover, which illuminates the surface through the aperture, so that the illumination is reflected from the surface by means of the aperture to the detector; and A filter that covers the aperture that passes the determined wavelength while blocking light at other wavelengths at which the detector is sensitive. Further provided, according to a preferred embodiment of the present invention, is an apparatus for determining the relative movement of a surface with respect to the apparatus, which comprises: A cover having an opening formed therein; A detector inside the cover that produces a signal used to determine the relative movement; A laser illumination source of a certain wavelength, inside the cover, which illuminates the surface through the aperture, so that the illumination is reflected from the surface by means of the aperture to the detector;
A second detector inside the cover that receives the illumination reflected from the surface; and A circuit system that shuts down the source of illumination when the illumination received by the second detector falls below a threshold; Preferably, the circuit system can be operated to periodically turn on the source and turn it off if the illumination received by the second detector is below the threshold. Preferably, the aperture is covered by a filter that passes the determined wavelength while blocking the light at other wavelengths at which the first and second detectors are sensitive. In a preferred embodiment of the present invention, a part of the illumination to the detector illuminates the detector, without said first part colliding with the surface, said part acting as a local oscillator for coherent detection of the illumination reflected by the detector. In a preferred embodiment of the present invention, the reflected illumination is changed by the Doppler system, by said translation, with respect to the illumination produced by the source and said Doppler shift is used in the determination of the movement. Further provided, in accordance with a preferred embodiment of the present invention, is an apparatus for measuring relative movement between the apparatus and a surface, which comprises: A source of illumination, which is used to illuminate the surface; A detector, which receives the illumination from the source, reflected from the surface and which receives a portion of the illumination without said portion being reflected by the surface, so that the detector generates a signal based on the coherent detection of the illumination reflected from the surface with the illumination portion as a local oscillator, wherein said signal has a frequency related to a relative movement rate; and A motion calculator that calculates the relative amount of movement in response to a zero crossing count of the signal. Preferably, the detector includes a high pass filter that filters the output of the detector to form said signal. Preferably, the high pass filter has a lesser inclination of about 20dB / eighths. Preferably, the high pass filter has a breaking point at a frequency corresponding to a movement rate of less than about 0.5 mm / sec. Preferably, the apparatus includes: A second detector that detects at least a second part of the illumination reflected from the surface to form a second detected signal using coherent detection, and the motion detector determines the relative amount of movement based on a change Doppler of the reflected radiation, wherein the detected signal and the second signal are in quadrature of the phase, and the detection comprises the detection of the quadrature. There is further provided, in accordance with a preferred embodiment of the present invention, an apparatus for determining the relative movement of a surface with respect to the apparatus which comprises: A cover having an opening formed therein; A detector within said cover that produces a signal used for relative movement to be determined; A laser illumination source of determined wavelength, inside the cover, which illuminates the surface through the opening, so that the illumination is reflected from the surface by means of the opening to the detector; and A circuit system that shuts down the source of illumination when the illumination received by the detector from the surface is less than a threshold. Preferably, the circuit system can be operated to periodically turn the source on and off if the illumination received by the surface detector is below the threshold. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: The placement of an object that partially transmits as part of an apparatus measuring, adjacent to the surface; The illumination of the surface with incident illumination so that the illumination is reflected from some portions of the surface, wherein at least part of at least one incident and reflected illumination passes through the object; Detecting the illumination reflected from the surface, to generate a detected signal, wherein the object and the surface are located within a distance that is less than the coherence length of the detected illumination; and The determination of the relative movement of the surface parallel to the surface, from the detected signal. Preferably, the transmission of the object is spatially variable. In a preferred embodiment of the present invention, the object is partially reflecting and part of the incident illumination is reflected or diffracted by the object, such as a reference illumination and the detection of the illumination is coherent using said reference illumination. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises:Placement of a partially reflecting object, which is part of the measuring apparatus, adjacent to the surface; The illumination of the object with incident illumination so that part of the incident illumination is reflected or diffracted by the object, as a reference illumination and part is reflected from the surface; The coherent detection of the illumination reflected from the surface using the reference illumination, to generate a detected signal; and The determination of the relative movement of the surface parallel to the surface, from the detected signal. In a preferred embodiment of the present invention, the object is an object that transmits partially and at least part of at least one reflected incident illumination passes through the object. Preferably, the reflection of the object is spatially variable. Preferably the spatial variation comprises a periodic spatial variation. In a preferred embodiment of the present invention, placing an object adjacent to the surface comprises placing a grid adjacent to the surface. Preferably, the placement of a grid adjacent to the surface comprises placing the grid sufficiently close to the surface so that the surface is in a near field of the grid. Alternatively, the adjacent placement of the grid adjacent to the surface comprises placing the grid sufficiently apart from the surface so that the surface is outside the near field of the grid. In a preferred embodiment of the present invention, the detected illumination is at least partially coherent. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: The placement of a grid, which is part of the apparatus of measurement adjacent to the surface; The illumination of the grid with incident illumination so that at least part of the illumination is incident on and reflected from the surface, wherein at least one of the incident and reflected illumination passes through the grid; Detection of the illumination reflected from the surface using the reference illumination; The generation of a signal in response to reflected illumination; and Determination of the relative movement of the surface parallel to the surface, from the detected signal. Where the surface is in the near field of the grid. Preferably, the illumination reflected from the surface is frequently changed from the illumination reflected from or diffracted by the object and the determination of the movement comprises the determination of the movement based on the change in frequency.
Preferably, the determination of the movement comprises the determination of the variations in the amplitude of the signal with the position. Preferably, the movement is determined from the crosses 0 of the detected signal. In a preferred embodiment of the present invention, the object has a transmission characteristic that is spatially non-symmetric. Preferably, the method includes the determination of relative movement based on a characteristic of the signal caused by said asymmetry. Additionally, according to a preferred embodiment of the present invention, there is provided a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: The placement of a partially transmitting object, which is part of the measuring apparatus, adjacent to the surface; Illumination of the surface with incident lighting, which does not constitute an interference pattern so that illumination is reflected from portions of the surface, where at least part of at least one of the incident and reflected illumination passes through of the object; The detection of reflected light from the surface and the generation of a detected signal; and The determination of the relative movement of the surface parallel to the surface, from the detected signal. Preferably, the method includes the phase variation between the illumination reflected from or diffracted by the object and at least a portion of the illumination reflected from the surface. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Illumination of the surface with incident illumination so that illumination it is reflected from portions of the surface; The placement of a partially reflecting object, which is part of the measuring apparatus, adjacent to the surface, where part of the incident illumination is reflected or diffracted by the object, such as a reference illumination; The coherent detection of the illumination reflected from the surface, using the illumination reflected from or diffracted by the object as a local oscillator, to form a signal; The determination of the relative movement of the surface from the signal; Variation of the phase of at least a part of the illumination reflected from or diffracted by the object with respect to at least a part of the illumination reflected from the surface; and The determination of the direction of relative motion parallel to the surface based on a characteristic of a signal caused by said varying relative phase. Preferably, the placement of a reflector adjacent to the surface comprises the placement of a grid adjacent to the surface. In a preferred embodiment of the present invention, the variation of the phase comprises the periodic variation of the phase. Preferably, the determination of the direction of relative movement comprises the determination of the direction of relative movement based on a characteristic of the signal caused by said relative phase of periodic variation. In a preferred embodiment of the present invention, the variation of the phase comprises causing the object to move periodically substantially in the direction of the movement being measured. In a preferred embodiment of the present invention, the variation of the phase comprises causing the object to move periodically substantially parallel to the direction of movement being measured. In a preferred embodiment of the present invention, the variation of the phase comprises: Providing a transparent material between the object and the surface; and Electrify the material so that it varies its optical length in the direction of illumination. Preferably, the transparent material is a piezoelectric material. Preferably, the method includes the determination of both the magnitude and the direction of translation using a single detector. In a preferred embodiment of the present invention, the variation of the phase comprises, the introduction of a static phase change and the determination of the relative motion direction comprises the determination of the direction of relative movement based on a characteristic of the signal caused by said phase change. Preferably, the method includes the division of at least part of the illumination that is reflected from the surface between at least a first illumination having a first phase and a second illumination having a second phase. Preferably the first and second illuminations have different polarizations. Preferably, the division comprises passing the incident illumination on the surface through a birefringent material. Preferably, the method includes passing the illumination reflected from the surface through a birefringent material. Preferably the method includes the placement of the birefringent material between the object and the surface.
In a preferred embodiment of the present invention, the method includes determining the magnitude and direction of translation using two detectors which produce different detected signals depending on the direction of translation. Preferably, the method includes determining the direction of translation from the sign of a phase difference between those of the different detected signals; Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Placement of a perforated reflector, which is part of the apparatus of measurement, adjacent to the surface; The illumination of the surface with incident illumination so that the illumination is reflected from portions of the surface and so that the illumination is reflected from or diffracted by the perforated reflector; The coherent detection of the illumination reflected from the surface using the illumination reflected from or diffracted by the perforated reflector as a local oscillator to form a signal; Determination of the relative movement of the surface perpendicular to and parallel to the perforated reflector from the signal. Preferably, the coherent detection comprises: Detection of the amplitude or phase variations of the reflected illumination; and The detection of a frequency change of the reflected illumination; and The determination of the relative movement comprises: Measuring the relative movement of the surface in a direction parallel to the perforated reflector in response to at least one of the variations in amplitude or phases detected; and The measurement of the relative movement of the surface in a direction perpendicular to the surface of the perforated reflector in response to the detected frequency change. Preferably, the method includes: Periodic movement of the surface of the perforated reflector in a direction perpendicular to its surface to add a periodic phase change to the illumination reflected therefrom; Y
The use of said phase change to measure the movement of the surface. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: The illumination of the surface, from a source, with incident lighting so that the illumination is reflected from portions of the surface towards a detector; The spatial filtering of the reflected illumination so that the phase of the optical illumination detected from a given separator on the surface is substantially constant or is linearly related to the translation of the surface; Generation of a signal by the detector in response to incident illumination in the detector; and The determination of the relative movement of the surface from the signal. Preferably, the illumination comprises the illumination of the surface with a spatially variable illumination. Preferably, the illumination of the surface comprises the illumination of the surface through a perforated reflector positioned adjacent to the surface which reflects or diffracts the illumination to the detector. Preferably, the generation of a signal comprises the coherent detection of the illumination reflected from the surface using the reflected or diffracted illumination from the perforated reflector. Preferably, the determination of the relative movement comprises the use of a Doppler change of the reflected illumination. Preferably, the illumination of the surface is substantially collimated; and the spatial filter filters the reflected illumination so that substantially only a simple spatial frequency of the reflected illumination is detected by the detector. Preferably, the illumination of the surface is substantially collimated and the spatial infiltrating filter filters the reflected illumination so that only illumination reflected from the surface substantially in a single direction is detected by the detector. In a preferred embodiment of the present invention, spatial filtering comprises focusing the reflected illumination with a lens having a focal point; and placing a minute aperture of an optical fiber in a simple way at the focal point of the lens to transfer the illumination to the detector. In a preferred embodiment of the present invention, spatial filtering comprises focusing the illumination reflected with a lens, placing a minute aperture in an image of the source. In a preferred embodiment of the present invention, spatial filtering comprises focusing the illumination reflected with a lens, and placing an optical fiber of a simple mode on a source image to transfer the illumination to the detector. There is further provided, in accordance with a preferred embodiment of the present invention, a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Placing an object that has at least transmission functions almost continuous, adjacent to the surface;
Illumination of the surface with incident illumination so that the illumination is reflected from portions of the surface towards a detector; Detecting the illumination reflected from the surface using the detector to generate a signal; and Determination of the relative movement of the surface from the signal. Preferably, the object has asymmetric transmission functions, and the determination of relative movement comprises the determination of the direction of movement based on the detected signal. Preferably, the illumination is reflected from or diffracted by the object towards the detector; and detection is a coherent detection using the illumination reflected from or diffracted by the object as a local oscillator to form a signal. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Illumination of the surface with illumination, through a perforated reflector , so that the illumination is reflected from the surface to illuminate a detector with illumination which is not an image of a point on or a portion of the surface;
The simultaneous illumination of the detector with the reference illumination derived from said incident illumination; and The coherent detection of the reflected illumination of the detector using said reference illumination so that the detector generates a signal; The determination of the relative movement of the surface parallel to the surface, based on the variations of the signal caused by the relative movement. Preferably, the incident illumination is at a certain wavelength, and the reference illumination is at the same wavelength so that the coherent detection is a homodyne detection. Preferably, the method includes the spatial variation of the illumination of the surface. Preferably, the spatial variation of the surface illumination comprises the illumination of the surface through a transmission grid having a spatially variable periodic transmission. Preferably, the spatial variation of the surface illumination comprises the illumination of the surface through a grating which specularly reflects a portion of the incident illumination thereon towards the detector to form said reference illumination. Further provided, according to a preferred embodiment of the present invention, is a method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: Illumination of the surface with illumination so that the illumination is reflected from portions of the surface; Placement of a perforated reflector adjacent to the surface;
The coherent detection of the illumination reflected from the surface, using the illumination reflected from or diffracted by the perforated reflector as a local oscillator; and The determination of the relative movement of the surface, in a direction parallel to the surface, from a characteristic of the signal. Preferably, the relative movement is detected using a Doppler shift of the illumination reflected from the surface. Preferably, the perforated reflector is a grid and the illumination diffracted by the grid is used in determining the movement. In a preferred embodiment of the present invention, the illumination is incident perpendicularly on the surface. In a preferred embodiment of the present invention, the surface is an optically reflective surface diffusely. In a preferred embodiment of the present invention, the surface has no markings indicating the position.
Preferably, the illumination comprises the visible illumination. Alternatively or additionally, the illumination comprises infrared illumination. It is additionally provided, according to a preferred embodiment of the present invention, an apparatus for determining the relative movement of a surface and said apparatus comprises: A partially transmitting object located adjacent to the surface; A detector that detects incident light on and generates a detected signal. A source of illumination which illuminates the object with incident illumination so that the illumination is reflected or diffracted towards the detector from the object and so that part of the incident illumination is reflected from the surface towards the detector, so that the detector coherently detects the illumination reflected from the surface using the reflected or refracted illumination towards the detector of the object; and A circuit system which determines the relative movement of the surface with respect to the apparatus from the detected signal. Further provided, in accordance with a preferred embodiment of the present invention, is an optical mouse which comprises: A cover having a face of the perforated surface; and An optical motion detector which sees the surface through the aperture, wherein the optical motion detector uses the method of the present invention to determine the translation of the cover relative to the surface. There is further provided, in accordance with a preferred embodiment of the present invention, a contact point for use as a control apparatus, which comprises: A cover having an opening; and An optical detector which determines the movement of a finger which is translated to the width of the aperture. Preferably, the optical detector uses the method of the present invention to determine the translation. Further provided, in accordance with a preferred embodiment of the present invention, is a pointing apparatus, which comprises: A first contact point in accordance with the present invention and a circuit system which moves the flag in response thereto; and A second point of contact according to the present invention and including a circuit system which causes a spiral response thereto. Further, in accordance with a preferred embodiment of the present invention, a mouse / point of contact combination is provided for use as a pointing device for a computer, which comprises:
A cover that has an opening; An optical detector which determines the movement of an object which is translated across the width of the aperture; and Means to determine whether the opening is oriented up or down. Preferably, the optical detector uses the method of the present invention to determine the translation. Further, according to a preferred embodiment of the present invention, there is provided an explorer for reading a document by means of the movement of the scanner on the document, which comprises: An optical reading head which detects patterns on the surface of the document; and An optical detector which determines the movement of the scanner as it travels across the surface of the document, wherein the optical detector uses the method of the present invention to determine the translation. Preferably, the patterns comprise printed patterns. Alternatively or additionally, the patterns comprise handwritten patterns. Alternatively or additionally the patterns comprise a signature. Further provided, in accordance with a preferred embodiment of the present invention, is an encoder comprising: An optically diffusing reflecting surface; and An optical detector having a relative movement with respect to the surface, wherein the optical detector measures the relative movement with respect to the surface without using marks on the surface. Further provided, in accordance with a preferred embodiment of the present invention, is an encoder which comprises:
An optically diffusing reflective surface that has no marks except the reference marks; and An optical detector having a relative movement with respect to the surface, wherein the optical detector measures the relative movement with respect to the surface relative to the reference mark. Preferably, the surface is the surface of a disk which rotates about an axis and wherein the detector measures the rotation of the disk. Preferably, the encoder uses the method of the present invention. Further provided, in accordance with a preferred embodiment of the present invention, is a virtual pen which comprises: An encoder according to the present invention; and A circuit system which translates said relative movement measured within written or graphic data.
There is further provided, in accordance with a preferred embodiment of the present invention, an apparatus for moving a sheet of paper, which comprises: Means for moving the paper; and An optical detector which measures the movement of the paper without using any marking of the paper. Preferably, the optical detector uses the method of the present invention. It is further provided, in accordance with a preferred embodiment of the present invention, an apparatus for moving a blade according to the present invention; A reading head, which reads the information from the paper; and A memory which stores the information in the memory locations in response to the measurement of the movement of the paper. There is further provided, according to a preferred embodiment of the present invention, a printing machine, which comprises: An apparatus for moving a sheet according to the present invention; A memory in which it contains information that is going to be printed on the sheet of paper; and A print head which prints the information in response to the measurement of paper movement.
Additionally, according to a preferred embodiment of the present invention, a fax machine comprising an explorer according to the present invention is provided. Further, according to a preferred embodiment of the present invention, there is provided a fax machine which comprises a printer according to the present invention. Further provided, according to a preferred embodiment of the present invention, is a method for determining the direction of relative movement of a surface with respect to a measuring apparatus which comprises: Illumination of the surface with incident illumination so that the illumination is reflected from portions of the surface towards a detector; The placement of an object, which has an asymmetric transmission function adjacent to the detector; Detecting the illumination reflected from the surface using the detector to generate a signal; and Determination of the direction of relative movement of the surface from the signal.
Brief Description of the Drawings. The present invention will be understood more clearly from the following detailed description of the invention, which should be read in conjunction with the accompanying drawings in which:
Figure 1 is a schematic representation of a preferred embodiment of a motion transducer, in accordance with a preferred embodiment of the present invention. Figure 2 is a graph of a grid transmission function, according to a preferred embodiment of the present invention; Figures 3A, 3B and 3C are schematic representations of preferred embodiments of integrated motion translators, in accordance with preferred embodiments of the present invention; Figure 4 is a schematic diagram of an optical mouse according to a preferred embodiment of the present invention; Figures 5A and 5B are schematic diagrams of a mouse / finger translation measuring apparatus, according to the preferred embodiment of the present invention. Figure 6 is a schematic diagram of a scout pen according to a preferred embodiment of the present invention; Figure 7 is a diagram of a rotation encoder, according to a preferred embodiment of the present invention; Figure 8 is a schematic diagram of a fiber optic-based translation measurement apparatus according to a preferred embodiment of the present invention; Figure 9 is a simplified and generalized block diagram of an electronic circuit system, suitable for use in the preferred embodiments of the present invention.
Figure 10 is a simplified diagram of a translation measurement apparatus according to a preferred alternative embodiment of the present invention. Figures 1 1 A and 1 1 B, further illustrate another preferred embodiment of the present invention. Figures 12A and 12B, illustrate the principle of a preferred embodiment of the present invention that uses a mechanical shift system to determine the direction of movement of a translation measurement apparatus, in accordance with a preferred embodiment of the present invention; Figures 13A through 13D illustrate the principles of two preferred additional embodiments of the present invention utilizing a mechanical shift system to determine the direction of movement of a translation measurement apparatus; Figures 14 through 16 illustrate the principles of a three translation measurement apparatus, according to a preferred embodiment of the present invention which do not use a grid; Figures 17 and 18 illustrate the principles of two additional motion detectors, in accordance with the preferred embodiments of the present invention, which measure the movement of the surface based on a Doppler shift; Figures 19A and 19B schematically illustrate integrated structures operating in accordance with the same principles as the apparatus of Figures 15 and 16, combined with direction detection as in Figures 3C, 17 and 18;
Figures 19C and 19D schematically illustrate details of a detector module used in some preferred embodiments of the present invention; Figures 20A and 20B, illustrate two views of a general structure of an apparatus for the measurement of rotation of a relatively small axis, according to the preferred embodiments of the present invention; Figure 21 schematically illustrates a configuration of the detectors useful for reducing motion effects, normal to the surface, in motion measurements parallel to the surface, in accordance with a preferred embodiment of the present invention; Figures 22A to 22D schematically illustrate various configurations of detectors, in accordance with preferred embodiments of the present invention, to determine two-dimensional movements along the plane of a surface; Figure 23 illustrates the graphs of the cursor speed as a function of surface velocity for different filtration techniques; Figure 24 illustrates a diffraction grating useful in a preferred embodiment of the present invention; Figure 25 illustrates a second diffraction grating produced in accordance with a preferred embodiment of the present invention; and Figures 26A through 26C illustrate the placement of the source, the detector and the grid in which the detectors are positioned away from the specular reflection of the surface, in accordance with a preferred embodiment of the present invention; and Figure 27 is a schematic circuit drawing of a preferred embodiment of a bandpass adapter circuit, useful in some aspects of the present invention.
Detailed Description of the Invention. The apparatus 10 comprises an at least partially coherent, preferably collimated, optical radiation source 14, such as a laser. Preferably, the laser is a diode laser, for example, a low power infrared laser. Although other wavelengths may be used, an infrared laser is preferred because it results in a safe operation for the eyes at a higher power. The source is preferably collimated. Although it is desirable to use a collimated beam from the depth of field considerations, collimation does not need to be particularly good. However, a non collimated source can be used if the compensation is as described below. The apparatus 10 also includes a one or two dimensional reflector grid 16, which is spaced near the surface 12. The limitations with respect to the separation of the grid 16 from the surface 12 will now be described. Generally the space between the grid 16 and the surface 12 is a few millimeters or less. The light that is reflected from the grid 16 (or diffracted by) and the light reflected by the surface 12, both are preferably incident on a spatial filter (composed of a lens 18, and a minute aperture 20) before being detected by a optical detector 22. The resulting interference causes a pulse signal that depends on the movement of the surface. As indicated by Figure 1, the radiation is reflected from the surface and in substantially all directions. This radiation is omitted from some of the drawings for the purpose of clarity of presentation. In Figure 1, the light looks as if it were incident on the surface from an angle; however, it is possible for the light to be incident to normal to grid 16. In addition, although Figure 1 shows the angle of incident light equal to the detection angle, so that the light reflected from the grid (or a diffraction of the order of zero) is used for the local oscillator, the first order diffraction or higher by the grid, can be used effectively. The zero order has the advantages that it is the independent wavelength (wavelength stability is not important). The incident light can be pulsed or continuous. In Figure 1, the diffracted light in orders of -1 and +1, is indicated by the reference numbers 19 and 21 respectively; the light that is scattered on the surface is indicated by the reference number 17.
In the preferred embodiment of the present invention illustrated in Figure 1, coherent, spectrum-free detection (homodine or heterodyne, in Figure 1, homodine is illustrated) is used to determine it in tangential motion. Said detection results in an intrinsic amplification of the signal used for the resulting measurement in a high dynamic range. The reference field of the local oscillator for coherent detection is provided by the reflections of the grid 16, placed close to the moving surface. The interference of the reflections of the grid and the moving surface in the detector originate an oscillating signal dependent on the translation. The incorporation of a reflection close to the surface of a grid as the origin of the local oscillator field can provide multiple advantages, including at least some of the following: 1. The grid is a simple element that combines the roles of a lightning separator and a mirror in a coherent homodyne / heterodyne optical detection setting. Thus making the optical system simple, robust and with few alignment requirements. 2. The grid causes the spatially periodic intensity and / or phase modulation of the illumination reflected from the surface, if the surface is placed within the near field of the grid. This makes it possible to detect the translation using the specular reflection (zero order) as the reference wave.
3. The high-order defractions (+1 ro, + 2d0, etc.) of the grid serve as local fields of the oscillator for the detection of surface translation using the Doppler shift of the reflection of the surface. A change in the phase dependent on the translation between the reference waves and the surface in orders of non-specular reflection produces the oscillations representative of the translation. The resolution increases for the higher diffraction orders. 4. The detection of the translation can be inclined in its frequency by means of the periodic change of the position of the grid
(for example, toothed modulation), making it possible to determine the direction as well as the magnitude of the translation.
5. A two-dimensional grid provides the reference waves (local oscillator) and the modulation of the illumination of the surface and the reflections from it for two orthogonal directions for translation in a single element and for measurements of transverse movement in two dimensions . 6. The measurement in the different orders of the grid provide different components of the translation or the velocity vector of the surface. The specular reflection, for example, the translation along the perpendicular axis of the grid can be measured independently of the translation in the other directions. This allows the measurement of the three-dimensional translation. 7. The asymmetric functions of the transmission of the grid (amplitude and / or phase) make it possible to detect the direction in all the reflected orders, using the appropriate manipulation / analysis of the signal. 8. The inclination of the frequency using the local phase change of the oscillator, in combination with the amplitude modulation resulting from the grid in the near field provides the simultaneous measurement of the two-dimensional translation (in a transverse and axial translation plane) ) using a single detector. In addition to the restrictions related to spatial filtering, the allowed distance between the grid and the surface, generally depends on the period de of the grid, the wavelength of the light,, the width of the coherence of the spectrum,, the area illuminated and the angles of the incident and reflected ray. For those preferred embodiments of the present invention, which use the reflected or diffracted light from the grid as a local oscillator, it is most preferable for the spacing between the surface 12 and the grid 16 to be less than the coherence length of the light , provided by 8? 2 / ??, where ?? is the width of the spectrum of radiation that reaches the detector (and not necessarily the width of the spectrum of the light source). In addition, the coherence length of the source should preferably be greater than n? L / ?, to maintain coherence over the entire width of the ray, where L is the width of the illuminating beam. By correctly filtering the spectrum, along the optical path, the content of the spectrum reaching the detector can be limited, and its coherence length increased if this is necessary. For those preferred embodiments of the present invention, in which the modulated transmission pattern plays a major role in the detection scheme, the space between the grid and the surface 12, must also be within the distance of the near field of the grid, «? 2/4 ?. For the following spacing modes, they are assumed to be in the near field. This requirement is relaxed for cases where it is not essential. The relative movement of the surface can be measured in a number of different ways. Consider the incident field, and the transmission function of the grid field respectively:
E (t) = E0cos (? 0t) (1) A (x) = Scmcos (2pmx /? +? M) m (2)
It is assumed that the grid is a pure grid of amplitude with a period?, So that its transmission is the sum over non-negative spatial frequencies with real coefficients. A similar formalism is also applied to the binary phase grid, or to some general phase grids, which may also be used in the practice of the present invention. For the general case of both the amplitude and the phase of the grids, a phase retardation term is added. In order to simplify the description, the following description is based on a pure grid of amplitude. However, it should be understood that they may use other grids and that they are preferable for some embodiments of the present invention. Constant factors that are not important have also been omitted in several parts of the following mathematical treatments. Flat-wave illumination by the light source over the area of the grid is assumed (for example a collimated beam), but not stipulated strictly necessary, for example, the non-collimation is compensated in another part of the system (for example, the spatial filter). For simplicity objects it is assumed that the incident light is perpendicular to the grid (and not as illustrated in Figure 1). The oblique incident light (in the direction of the grid lines and / or perpendicular to it) produces substantially similar results, with changed reflection angles. In this way, the field of the grid contains a series of reflected diffraction orders, symmetrically arranged around the specular reflection component (zero order) and obeying the angular condition (for the n-th order):
sin (a) = n? / ?. (3)
As illustrated in Figure 1, the spatial filter in front of the detector preferably comprises lenses, focus lenses 18, and narrow minute aperture 20 at the focal point of the lens. Said spatial filter is preferably adjusted to select only a single spatial frequency component to reach the detector. The aperture can be replaced by a simple optical fiber, having a similar core diameter and directing the light to a remote detector. The spatial filter is aligned so that one of the diffraction orders reaches the detector, and serves as a local oscillator for homodyne detection of the reflected radiation, or for heterodyne detection as will be described below. The local oscillator field is provided by:
= LO (t) = In cos (coot + (pn) (4)
The reflected field of the moving surface in the same direction as the n-th diffraction order that is represented by an integral over the area of the illuminated surface of independent reflections from the surface. The integration on the direction parallel to the grid lines (y) and on the direction normal to that of the surface (corresponding to the penetration of light inside the surface), results in a reflected field equal to:
X2 Er (t) = Eo dxA (x) r (xp (t)) cos (? 0t + 2pnx /? + F (xp (t))) (5) Xi Where r (x) and f (x) are the amplitude dependent on the
location and the reflectance of the surface phase, respectively. It is assumed that the reflection is independent of the time during the measurement with both r and f being variable
random of the position x. The translation of the surface in its initial position is provided by p (t), with p (0) = 0. The periodic term of phase 2pnx /? originates from the reflection of an angle
sin (a) = n? / ?. The integration limits are from Xi to x2, both determined by the determined area. The change of the integration variable from x to x-p (t), corresponding to the symmetric situation of a static surface and the grid moving with respect to the system coordinated by the reference:
x2-p (t) Er (t) = Eo xAx (x + p (t)) r (x) cos (w0t + 2pnp (t) / L + 2pnx / L + f (x)) (6)
XrP (t)
With integration limits that now extend from xi-p (t) to X2-p (t) thus being time dependent. Replacing A (x) with the Fourier series and writing fn (x) = f (x) + 2pnx / A is provided:
X2-P (t) Er (t) = Eo JdxScmcos (2pmx /? + 2pmp (t) /? +? M) r (x) cos (? 0t + 2pnp (t) /? + Fn (x)) Xrp (t) m
(7) The (optical) phase of a separator in the linearity of the surface depends on the translation p (t), with f = fn (x) + 2pnp (t) / ?. For specular reflection (n = 0), the phase is a constant. Both, the reflected field and the field of the local oscillator reach the detector. Since the detector measures the intensity, which is proportional to the square of the field, the intensity is provided by:
l (t) = (ELO (t) + Er (t)) 2 = ELO (t) 2 + 2ELO (t) Er (t) + Er (t) 2
Suppose that the field of the local oscillator is much larger than the reflected field, E or > > Et and that the integration time of the detector is much longer than the optical time of the period, but much shorter than? / NVmax (where vmax is the maximum measured speed). Integration over the optical frequencies provides only one CD component while other variations are detected instantaneously. According to these assumptions, the first intensity term is replaced by a constant I LO = 0.5ELO2, and the third intensity term is omitted, for example, lr = 0.5Et2 = 0. In this preferred embodiment of the present invention, the proportion of the resistance of the local field of the oscillator and of the reflected field is intrinsically large, since the reflection from the grid is directed only to narrow specific orders, and the reflection from the diffuse surface it is scattered at a wide angle.
Although the following explanation assumes that the third term is zero, the measurement of translation that uses spatial modulation is possible even if the third term is only present, for example, when the light reflected from the surface is not combined with a light reflected or diffracted from the grid. This can be achieved (if desired) by selecting an angle that rests between grid orders. This has the advantage that relaxed alignment is significantly stressed (it only requires that the light is in the focal plane), but will generally be less accurate, and with a low ratio of signal to noise. The local oscillator field serves as a very strong amplifier in the first stage of signal detection. In this regard, it is strongly preferred to keep the field of the local oscillator as noise-free as possible, since its noise is transferred directly to the detected signal. The measured cross term is equal to:
ls (t) = Encos (? 0t + Cpn) Er (t) (9)
Inserting the term of the oscillator field cos (? Ot) in the integral for Et (t) and using the ratio of cosine sum cossacos = 0.5 (cos (a + ß) + cos (-ß)) for cosine plus a the right in (7), you get an intensity component twice the optical frequency (2? o) and another with a phase that varies slowly. The fast oscillation component is averaged to zero due to the detector's time response. The remaining signal is:
x2-p (t) (t) = lp J dxScmcos (2pmx /? + 2pmp (t) /? +? m) r (x) cos (2pnp (t) /? + fn (x) -fn)
XrP (t) m (10)
Exchanging the sum with the integration, the contribution to the sum of each term is: X2-P (t) ls m (t) = InCm idxcos (2pmx /? + 2pmp (t) / A +? M) r (x) cos (2pnp (t) /? + Fn (x) -fn) XrP (t) (11)
Assuming that co, c? > > . { cm, m > 1 } . The last requirement allows us to concentrate on only two terms in the sum on the grid harmony, the terms m = 0 and m = 1. For these two terms we can write:
X2-P (t) ls, or (t) = lnCo Jdxr (x) cos (2pnp (t) /? + Fn (x) -fn) X? -P (t) (12)
X2-P (t) ls? (T) = lnc? Jdxcos (2px /? + 2pp (t) /? +? 1) r (x) cos (2pnp (t) / A + fn (x) -fn) X? -P (t) (13)
Now the attention is focused on the specific orders of diffraction in the waves reflected and refracted in the grid, the directions n = 0 (specular reflection) and n = ± 1.
For the term of specular reflection, the contribution m = 0 is:
X2-P (t), or (t) = crazy idxr (x) cos (f (x)) XrP (t) (14) For a diffuse surface with constant brightness, this term will be almost constant and will change slowly as and when changes the average reflection of the surface. The term m = 1 is:
X2-P (t) ls 1 (t) = l0C? jdxcos (2px /? + 2pp (t) / A +? i) r (x) cos (f (x)) = XrP (t)
X2-P (t) cos (2pp (t) /?) LoC? Jdxcos (2px /? +? I) r (x) cos (f (x)) XrP (t) (15) X2-p (t) sin (2pp (t) /?) L0C? idxsen (2px /? + ??) r (x) cos (f (x))
cos (2pp (t) /?) lc (t) + sin (2pp (t) /?) ls (t) = l (t) cos (2pp (t) /? +? (t))
Where the intensity l (t) and the phase T (t) results in the integrals on the random variables corresponding to the amplitude and the phase reflection of the diffuse surface at a spatial frequency 1 / A. For diffuse surfaces with reflectors
simple larger than the spatial wavelength A contribution will come from the granular boundaries, while the diffuse surfaces that have small particle sizes will be strong contributions for all spatial frequencies up to 1 / d, where d is the average particle size . The rate of change of these variables of "random walks" depends on the average time that takes you to a set of reflection centers. { x¡} to be placed by a new set, which at the same time is related to the change of the upper integration region, t oc (x? -x2) / v = L / v, where v is the instantaneous velocity and L is the illuminated size of the grid. If grid periods are illuminated in larger amounts such as L > > ?, the result is fast oscillations with amplitude and phase statistics that vary slowly. The measurement error of the translation is proportional to A / L and depends on the speed. In summary, for the mirror measurements of translation measurement: 1 The signal measured at the output of the detector oscillates at a frequency of v /? The detection and counting of the zero crossing points of this signal provide a correct measurement of translation, each zero crossing corresponding to a translation? P =? / 2, provided that the direction of translation does not change during the measurement. 2. The amplitude of the measured signal of the phase are slowly changing statistical assembly sums. The relative accuracy of the measurement is proportional to? / L, where L is the illuminated size of the grid. 3. The space between the surface and the grid should preferably be smaller than both, the distance from the field
close, «? 2/4? and the coherence length that the detector reaches
"?2/??
First-order reflection, unlike mirror reflection, also carries a Doppler phase shift. Looking again at the contribution of m = 0, 1 and the spatial frequency components is provided:
X2-P (t) ls, or (t) = co Jdxr (x) cos (2pp (t) /? -f? (X) -f? X? -P (t) (16)
x2-p (t) ls 1 (t) = 11 ci jdxcos (2px /? + 2pp (t) /? +? i) r (x) cos (2pp (t) /? + fi) - ^) xi - P (t) (17)
Using a decomposition of the term cosine in both (16) and (15), we have as a result:
ls, o (t) = l0 (t) cos (2pp (t) /? +? 0 (t))
In a similar way the expression for the term m = 1, (17) is: ls,? (T) = (t) cos (4pp (t) /? +? ^ T)) (19)
Equation (19) omits a slowly varying term which is added to the average detector signal (the "CD" component). An analysis of the equations from (16) to (19) shows that if Co > > c? , the zero crosses of the signal correspond to p = 2, while if co < < c? , the zero crosses correspond to p =? / 4. This result can be expanded to other reflection orders n > 1, where, if co > > C? , the measured signal will oscillate according to np (t) / ?. For jn | > 1, the quantity of the term ci for the oscillations in the bands of two sides around the oscillations co as in the amplitude modulation of the highest frequency signal. Note that the term m = 0 does not require near field conditions, so setting the distance to the moving surface, so that it is larger than the near field boundary? 2/4? (but preferably less than the coherence length? 2/4?) the contribution m = 0 is dominant. Alternatively, a transmission function for the grid was preferably used so that Co > > c? still in the near field. In a preferred Doppler operating mode, a grid was used to generate a local oscillator field by diffracting the incident illumination towards the detectors. However, diffraction orders may also exist in the transmission (for example, when a pure grid of amplitude is used). These commands can result in multiple beam illumination of the surface even outside the near field of the grid and in the diffraction of illumination reflected from the surface towards the multi-ray detector. In this way, each detector will detect a multitude of Doppler components, each corresponding to the Doppler change of a combination of transmitted and reflected orders, interfering with the field of the local oscillator that illuminates the detector, constituting a 'crossed optical dialogue'. In a preferred embodiment of the present invention, the illumination of the surface is done by a single beam, eliminating the 'crossed optical dialogue'. In a similar way, it is desirable that the illumination reflected from the surface is not diffracted by the grid. Therefore, the non-zero transmission orders of the grid should be minimized and preferably eliminated. A diffraction grating is preferably used for the generation of local oscillator fields using the orders in the reflection, and designed to have virtually only one transmission order (for example, a single beam illuminating the surface and that the illumination of the surface does not constitute an interference pattern on the surface). Also, the illumination reflected from the surface is not diffracted forward as it passes through the grid to the detectors, as desired. Referring to Figure 24 which illustrates an example diffraction grating 800, which incorporates this principle. Suppose the grid is a binary phase grid with a refractive index of ng, suspended in a medium of another ns refractive index. Preferably, the grid has square grooves 802 of depth h. For the normal incident illumination 804, the relative phase difference in the reflection from the inner side 806 of the grid is Pr = 2ng * h /?, whereas for a transmitted ray 808 the relative phase difference is Pt = (ng - ns) # h / ?. Negligible high orders will be obtained when Pt is a natural number, so that the minimum depth of the slot is h = K / (ng - ns). At the same time, the efficiency of the reflection depends on the difference of optical phase in the reflection, which after the substitution of the depth of the grid is: Pr =. Assuming there is air on the transmission side of ng -ns a grid (ns = 1) and the zero-order reflection is being minimized
(Pr = M + 1/2, natural M), then: "" M = 5, the wavelength of 859 nm and a refractive index ng = 1.57, depth of the grid of approximately 1.5 microns will give as a result, an optimum efficiency of the return diffraction is ideal, only the transmission of zero order. Figure 25 illustrates another method of producing a grid 810 that has substantially only zero order transmission and that has at least first order return diffraction. According to a preferred embodiment of the present invention, a diffraction phase grating 812 is coated by a metal (or dielectric) layer 814, which functions as a partial reflector with a controlled reflection coefficient. This coating can be made, for example, by means of the electronic deposition or evaporation of the coating material on the surface of the grid. The other side of layer 814 is filled by an optical means 816 with a refractive index essentially equal to that of the grid material. Conveniently, this material can be an optical glue that adheres the grid to a polarizer, a wave plate or a protective glass, indicated by the reference number 818, or an epoxy mold that combines the elements 816 and 818. this construction, any difference of the optical path generated by the grid on the transmitted radiation is compensated for by a corresponding optical path difference in the optical glue, so that the front phase is not altered at the output of the compound distribution. Therefore, substantially, there are no transmission orders, except the zero order. On the other hand, the return diffraction is achieved by the difference in the phase of the reflections from the layer 814 at different locations, for example, the inner end 820 of the slots 802 and the outer end 822 of the slots. An advantage of the method illustrated in Figure 25 is the convenient control of the reflected (and diffracted back) power transmitted from the grid illumination, altering the reflection and transmission of layer 814. This effect can be used , for example, to maximize the signal to noise and to limit the emission of a safe level for the eyes.
The method of eliminating the diffraction of a grid in the transmission, illustrated in Figure 25, is appropriate for complex phase patterns, and not only for binary phase grids. It can also be applied to diffraction lenses and other diffraction optical elements for which independent control of transmission and reflection is desired. The transmission can also be modified by a second diffraction or refraction characteristic on the other outer surface 824 of the optical element. The frequency associated with the oscillations Co also depends on the axial (perpendicular) transverse translation component (described below). On the contrary, the modulation of the amplitude (through the component c-i) depends only on the transversal component. When the frequency of the co oscillations is sufficiently high, this frequency can be measured by the technique related to the frequency described above, simultaneously with the detection of the amplitude modulation frequency to measure the transverse translation component. Thus, measurement of two-dimensional translation (including movement perpendicular to the plane of the surface, e.g., axial translation) can be achieved using a simple detector. Inclining the frequency of the reference signal, the ratio between the carrier frequency and the amplitude modulation frequency can be made large, improving the accuracy of the measurement, as well as allowing the detection of the direction of translation. Also, the use of specular reflection from the grid as a local oscillator, makes it possible to make a clear distinction between the transverse translation component (indicated by the amplitude modulation) and the axial translation component (indicated by the phase change or frequency of the conveyor frequency). In addition, the phase change can be combined with an asymmetric transmission pattern of the grid (eg, a toothed pattern) for the purpose of detecting the transverse direction of translation. Alternatively, the grid can be shifted for direction detection in the two dimensions, or a static phase change is used, as will be explained in more detail below. In essence, for the non-specular diffraction modalities of the present invention, two near-plane waves are selected for detection by the detector. One of these waves is the result of the diffraction of the n-th order of the grid. The background wave is generated by selecting the wave of a plane (by the spatial filter) from the reflections of the surface. In summary the measurement of the translation used non-specular diffraction (and assuming a constant speed, for clarity of explanation): 1. The signal measured at the output of the detector oscillates at a frequency of nv / ?, where n is the number of order. The detection and counting of the zero crossing points of this signal provides a measurement of direct translation, each zero crossing corresponding to the translation? / 2n, provided that the direction of translation is not changed during the measurement. 2. The measured amplitude and phase of the signal are sums of statistical set that vary slowly. The relative accuracy of the measurement is proportional to? / NL, where L is the grid size illuminated, which at the same time is preferably larger than n? L / ?. 3. The distance between the surface and the grid should preferably be less than the coherence length of the light reaching the detector, 2 2 /.. Even though the absolute translation of variable time I p (t) | , its address is determined preferably using one of the methods described below. In a preferred embodiment of the present invention, the direction can be determined by applying a phase change between the reference field (local oscillator) and the reflected field. This additional phase change can be manifested, for example, by moving the grid towards or away from the surface. This movement does not change the phase of the incident field on the surface, so that the field reflected from the surface is identical to that provided above. The local oscillator field, however, acquires an additional phase change, due to this translation that depends on the displacement of the grid d (t).
The distance between the grid and the surface can be kept almost constant and by introducing a fixed frequency change between the fields of the reflected and local oscillator, making d (t) a periodic toothed function:
co dn (t) = Dn J [t-1 -? d (f-kt)] dt '0 k = 0 (20)
considering t as the cycle time for the toothed function, setting the amplitude of the toothed function to obtain the 2p phase change (or multiples of 2p) for reflection in the n-th diffraction order. The frequency change due to this movement and if t "1> nv /? Is maintained, the direction of the movement is unambiguously determined according to the oscillation frequency of the detector signal, ie t" 1 + nv / ? Alternatively, the translation (both positive and negative) is determined directly by the count of the zero crossing in the detected signal and subtracting it from the result of a simultaneous count of the frequency t "1 of the oscillator.If the toothed amplitude is not ideal, (for example, it does not correspond to the whole multiples of the wavelength) the direction can still be determined, however, the formula is more complicated As used in the present description the term "toothed" includes such variations that are not An alternative way of introducing a periodic phase change between the field of the local oscillator and the field reflected from the surface is to modulate the length of the optical path between the grid and the surface, which is preferably achieved by means of an element transparent piezoelectric mounted between the grid and the surface An alternative methodology to break the symmetry between the relative translation , positive and negative, so that the direction of translation can be detected, is to use an asymmetric function for the transmission function (amplitude and / or phase) of the grid. For reasons of simplicity, the formula is developed for an amplitude grid. Let us suppose that the grid is large compared to the space of the line along the axis of translation and that the dispersers of point k are illuminated through the grid. Dispersers that enter or leave the illuminated area are omitted (this will appear as a noise factor in a general treatment). After the interference with the local oscillator (which is not changed here) and the filtering of the optical frequencies, the resulting signal can be written as:
? s? Jn 2 ^ ri A (xi + p (t)) cos (2pnp (t) /? + Fj) (21) i = l where rj, xj and fj are the reflectance, the position (at time t = 0) and the relative phase (with respect to the local oscillator), respectively, of a diffuser i. For a diffuse body these are all random variables. This presentation of the detector signal is used for the following address detection mechanisms. For specular reflection:
W = I? S *? A (xi + p (t)) cos (fi) (22) i = l
Assuming that p (t) = vt, for example, the changes in the velocity of the surface are relatively small during the integration time used for the determination of the direction of translation. Therefore, the first and second derivatives in the received signal are:
Is (t) = (23) k hit) = I0v2? Rich (fi) - (A (xi + vt)) i = l dx '(24)
d-A (x) dA (x) Suppose that A (x) is constructed so that ^ - =? - ~? - < hr? s (t) =? v-? s (t).
In this case it is evident that: In this way, the magnitude, and most importantly, the sign of the translation speed (for example, the direction of translation) can be derived from the ratio between the first and second derivatives of time of the detector signal. If it can not be assumed that the velocity is constant during the decision-direction integration time, then the derivatives can be realized with respect to the measured translation (which is known from the zero crossings or by another detector with greater accuracy). operated in parallel). If only the address is required (and not the magnitude of the speed), it is sufficient to check whether the first and second derivatives have the same sign (one direction) or not (opposite direction). A simple XOR operation (exclusive OR) after the detection of the sign of the derivatives will be "1" if the sign of? it is opposite to the sign of v and "0" if they are the same. An example of A (x) that satisfies the constant proportion of the derivative is a combination of exponents such as:
where the pattern is repetitive with a cycle A. It is evident that for this pattern the first and second derivatives (and indeed all) have a constant proportion, as required by? -? / ?. But, the singularity points in the multiples of? / 2 introduce "noise" to the measurement. These singularities increase the probability of error as the number of scatterers increases, since each will appear in the received signal when a scatterer passes through it. The relative contribution of noise is reduced as the integration time of the address detection increases. The pattern is supposed to be the intensity of the illumination on the surface. Therefore, the requirement of a near field is more demanding than the similar requirement for the magnitude of the translation measurement alone in a specular reflection n = 0. Figure 2 illustrates an assumed transmission pattern, for? = 5. This can be achieved by having a partial reflection / transmission property for the grid, having an amplitude function of the transmission, such as that shown in Figure 2. A relaxed requirement of the transmission pattern is that the derivatives will have a constant sign ratio (for example, they are not exactly proportional, but their sign of the proportion is constant along the pattern). Here, the detection of the direction is still ensured for a simple disperser, but the probability of error is greater than in the previous case as the number of dispersers increases (even without the effect of the singularities). A similar analysis is possible for high-order diffraction (| n | > > 1). Again, for reasons of simplicity, it is assumed that the surface will move at a constant speed, v. Equation (21) can be seen as a sum of the modulated amplitude signals of a conveyor with frequency nv / ?. Now it is assumed that A (x) is asymmetric (for example, toothed waveform). For | n | »1, the envelope of the detector signal coincides with the transmission function for the translation in the" positive "direction and is otherwise the inverse signal. Therefore, if the number of dispersers is small (the limit being dependent on the order n of the grid), the direction of the translation is represented by the sign of the first derivative of the envelope of the detected signal. In addition, the magnitude of the envelope derivative is proportional to the magnitude of the translation speed. An asymmetrical transmission pattern makes it possible to detect the direction for point velocimetry (speckie). The detector signal resulting from a random point pattern, filtered by a grid with a transmission intensity pattern A (x) adjacent to the detector, this can be represented as:
k - W = io ?? A (i + p (t)) (26) i = l
where rj and xj are the intensity and position of the "point" i-th, respectively, and p (t) the translation of the surface. Assuming a constant velocity, p (t) = vt, the time derivative of the detector signal is: ls (0 = I? V? Ri - (A (xi + vt)) (27) i = l
The intensities ri are positive values, so if dA / dx is constant, then the derivative of the detector signal is an indicator of the direction of translation. Said pattern is achieved using a jagged transmission pattern. The discontinuities in the pattern add noise to the measurement, requiring the use of an appropriate interval of integration in order to limit the probability of error. The speed of movement is determined from the frequency of oscillations of the detector signal. Of course, it is possible to use mechanical means or other means (for example, an accelerometer) to determine the direction of movement as a complementary component in an OTM apparatus. As noted above, fluctuations in the amplitude of the source are transferred directly to the signal received by the local oscillator field. In order to minimize such noise, according to a preferred embodiment of the present invention, a signal proportional to the amplitude of the source is detected and the resulting signal (called the detector and "compensation" signal) is subtracted from the detector signal. This detection can be carried out, for example: • Separating the ray from the source with a lightning separator (which does not need to be aligned exactly) and directing the deviated beam to the compensation detector, or • Directing any of the light rays diffracted from the grid to a compensation detector, without applying spatial filtering (but potentially with considerable attenuation). Conveniently, this can be one of the grid orders not used for the spatial filter measurement. , for example, use order 1 for the spatial filter and order 0 for the noise compensation of the source. • Directing one or more of the grid commands to one or more compensation detectors, so that reflection from the surface is blocked by a polarizer, as will be explained in detail with respect to Figure 19D. The output of the compensation detector is amplified (or attenuated) so that the resulting difference signal is as close to zero as possible when the surface is not moving relative to the device (or when the "window" is closed with an opaque cover), thus compensating for fluctuations in the energy of the local oscillator. The intensity detected (and the resulting detected signal) as described in Equation (8) includes an ELO2 component (= Eo2) of the local oscillator), a cross-section term, E0Er, and a second-order reflection term of the Er2 surface.
In order to compensate for the variations in the Eo multiplier of the Er component, the compensation detector signal may be the control voltage of a controlled gain amplifier in one of the steps of the signal amplification (after the first compensation , subtracting the component Eo2). The gain must be approximately proportional to the inverse of the square root. Preferably, to obtain the highest quality of the signal, the Er2 component is also compensated. This may be especially useful for those embodiments of the present invention that utilize an "effective minute aperture" (to be described later) to spatially filter the illumination reflected from the surface. In this embodiment, the exposed area of the detector on which component Er2 is integrated can be much larger than the area of the "effective aperture". The Er2 component can be compensated using a detector that does not detect a local oscillator field. The compensation detector can be placed so that essentially no order of the grid falls into it. Alternatively, it can detect only the polarized light so that any local oscillator field is effectively blocked. This can be implemented, for example, by placing a polarizer before the detector. Changes in the Er2 component are essentially caused by changes in the contrast on the surface, due, for example, to differences in the reflection coefficient of different colors. However, the reflection of a highly reflective surface (eg, laminated paper) is also sensitive to small changes in the angle of reflection near the specular reflection angle, as illustrated in Figure 26 A. For reasons of simplicity of presentation, Figures 26A through 26C show the perpendicular illumination of a grid 830 of a light source 832 and only one detector 834, in addition to a surface 836. In order to reduce the changes in the Er2 component , it is preferable to accommodate the source and detectors so that the detectors are positioned away from the specular reflection of the surface, as illustrated in Figure 26b. Alternatively, specular reflection of the surface towards the detectors can be avoided by tilting the entire component a few degrees with respect to the plane of the surface, opposite the directions of the detector, as shown in Figure 26C. However, the effect of the angle of inclination on the Doppler frequency must be taken into account. Preferably, a Z compensation (such as that described with respect to Figure 21) is used to significantly reduce the sensitivity of the measurement to the accuracy of the inclined angle. Figure 3 A shows a preferred implementation of a translation detector, according to a preferred embodiment of the present invention, in which zero-order detection is used and which does not incorporate address detection, or in which The detection of the direction is based on an asymmetric pattern of transmission of the grid and the analysis of the appropriate signal. Figure 3A shows an integrated optical chip translation apparatus 30 which is suitable for mass production. This device uses only a few components that can be manufactured in large quantities for a low price. The apparatus 30 comprises a laser diode 32, preferably a simple laser transverse mode. The laser light of the laser diode 32 is preferably collimated by a lens 34, which is preferably a collimating diffraction lens, etched into or deposited on the surface of an optical chip substrate 36 of glass, quartz or the like, preferably coated with layers. non-reflective on both sides except in the designated areas. A grid 38, which may be an amplitude and / or phase type grid, is mounted on the substrate of the optical chip 36. The grid 38 is preferably engraved or deposited on the lower surface of the substrate 36. The light reflected by the grid and the light reflected from a surface 42 are reflected by two reflecting surfaces 40 and 41 and focused by a lens 44, preferably a diffraction focusing reflector lens, etched into the surface of the optical chip substrate 36. The light is further reflected by the reflective surface 45. A minute aperture 46, is formed in a reflective / opaque layer formed in the focus of the lens 44, only a flat wave passes from the surface 42 and the reflected light from the grid 38 to a detector 50, for example, a photo diode of the type PI N or a similar device. Preferably, a compensation detector 52 is positioned behind the lens 44 and detects a portion of the light reflected by the grid 38. A controller 54 is used, which comprises a laser diode generator / modulator for activating the laser diode 32, amplifiers. of detection and zero-crossing counter circuits or frequency detection means for determining the translation or velocity of the surface. The compensation detector supplies a compensating signal proportional to the amplitude of the local oscillator to reduce any residual effects of variations of the laser output. For the reduction of noise, twisted cable pairs, protected cables or coaxial cable are preferably used to carry the signals to and from the controller 54. Preferably, the apparatus is provided with legs or a ring support 56 or other similar means on which the apparatus passes over the surface 42 to avoid damage to the grid and to maintain the distance between the grid and the surface fairly constant. Figure 3B shows a preferred alternative embodiment of the present invention including direction detection by phase change of the local oscillator and using the first order diffraction of the grid. The elements, which are functionally equal, have the same reference numbers in both Figures 3 A and 3B. Figure 3B shows an apparatus 60 in which the light of the laser diode 32 is collimated by a lens 62 to focus a grid 38. The grid 38 is preferably mounted on a piezoelectric ring 64 (which in turn is mounted on the an optical substrate 36). The excitation of the ring 64 adds a variable phase to the local oscillator (the light diffracted from the grid 38) in order to allow detection of the direction, as described above. In the embodiment shown in Figure 3B, both detection signals used for the detection of translation and direction on the one hand and for compensation detection on the other, are based on the first-order diffraction by the grid 38, but with an opposite sign. Preferably anti-reflective coating is used, where appropriate, to reduce unwanted reflections. An integrated optical chip is the preferred implementation scheme, since it can be manufactured in large volumes for a low cost. The figure illustrates only one detector for a single direction, preferably, with a second detector measuring the orthogonal direction. All optical elements - lenses, grille, mirrors and minute openings - are engraved inside or deposited on the optical substrate and are either reflectors or transmitters, according to the functionality. The separate components in the system - laser diode, detector and piezoelectric transducer - are mounted on the top of the chip. The electronic elements of the controller 54 can also be manufactured or placed on the top of the chip. It should be understood that the features of Figures 3A and 3B can be mixed and combined. For example, if in Figure 3A, the grid 38 is mounted on a transducer such as a ring 64, then the result would be an apparatus operating in the specular reflection mode (zero order) with increased dynamic range and possibly detection of the axial translation. In addition, it is possible to use an asymmetric grid in place of grid 38 and ring 64 of Figure 3B for purposes of direction detection. For these and other preferred embodiments of the present invention, experts in the art will be able to find several aspects of combination. Figure 3C shows still another embodiment of address determination, according to a preferred embodiment of the present invention. The apparatus 70 of Figure 3C is similar to the apparatus 60 of Figure 3B except that the grid 38 is placed on the bottom surface of the chip 36 and a birefringent plate 66 replaces the piezoelectric ring 65. The source 32 produces the linearly polarized light that it has a polarization that is at a 45 degree angle to the birefringent axis of plate 66. The radiation is reflected from the surface, passes through plate 66 twice and consists of two waves, each having an address of polarization at an angle of 45 degrees with respect to that of the radiation reflected from or diffracted from the grid 38,. These waves are also, ideally, a phase difference of 90 degrees one with the other. In addition, a beam polarizing separator 68 is preferably positioned before the detector 50. Its axis is such that a polarization is transmitted to the detector 50 and the orthogonal polarization is reflected to a detector 67. In addition, the beam splitter 68 directs half of the detector. the reflected or diffracted radiation from the grid 38 to each of the detectors 50 and 67. The resulting signals detected by the detectors 67 and 50 will have a phase difference of 90 degrees. The phase difference signal can be used to determine the direction of movement. Alternatively, a partially reflecting mirror is used to separate the radiation into two parts, and the orthogonal polarizers are placed in front of the two detectors to separate the polarizations. Preferably, the illumination of the grid is collimated. However, lighting without collimation can also be used, in which case the diffraction of the grid will be astigmatic (for example, it will no longer have a single focal plane). It is preferable to compensate for this effect so that spatial filtering is optimal for this purpose. In a convenient way, one or more lenses can be designed to correct the astigmatism of the grid. Alternatively or additionally, the grid itself may be designed to include astigmatic correction. It is expected that there are similar astigmatic effects and corrections in other diffraction elements illuminated by light without collimation. Although the present invention was described above in several modalities to solve the general problem of translation measurement, the methodology is applicable to a large number of products. A particular application of the optical translation measurement method of the present invention is a new optical cursor control apparatus (mouse) which derives its translation information from the movement in substantially any diffuse surface, such as paper or a desktop. A design of said apparatus, according to a preferred embodiment of the present invention, is illustrated in Figure 4. An optical mouse 80 comprises an "optical chip" 82 which is preferably an apparatus such as the apparatus 30, the apparatus 60, the apparatus 70 or a variation of these apparatuses. The chip 82 is mounted on a cover 84 and looks at the paper 42 through an optical aperture 86 in the cover 84. The input and output leads of the chip 82 are preferably connected to a printed circuit board 88 or the like on which the electronic circuit system 90 corresponding to the controller of the apparatuses 30, 60 or 70 is mounted. Also mounted on the printed circuit board 88 are one or more switches 92 that are operated by one or more buttons 94, as in conventional mice. . The mouse is conventionally mounted to a computer by means of a cable 96 or with a wireless connection. The measurement method according to the preferred embodiments of the present invention, described above, allows a wide dynamic range of translation speeds, covering the entire range required for the normal operation of a mouse. Said apparatus can be characterized as an "optical mouse without attenuator" to produce orthogonal signals to move a cursor from position to position on a screen, in response to the movement of the mouse on any diffusely reflecting surface, sufficiently such as a paper or a desktop. Therefore, special contrast markers or special patterns are not necessary. Mouse systems generally use mechanical transducers to measure the translation of the hand on the surface (usually a "mouse pad"). Nowadays, the need for a measurement technology to move the free, reliable parts is well recognized. Exactly, in mouse systems, some optical devices have been developed, but still suffer from several deficiencies, such as the need for a dedicated cushion with patterns, poor transduction or high cost operation, an optical mouse without attenuator according to a preferred embodiment of the present invention, it can be used in two ways, according to the user's convenience.It can be used as a "normal" mouse, where the mouse is moved on top of a surface, and its movement in relation with this surface is measured, it can also be skipped, if desired, and instead of using it for the movement of the finger along the aper The movement of the finger can be measured in relation to the body of the mouse, which is now stationary. One such apparatus 100 is shown in Figures 5A and 5B.
Figure 5 A shows that the apparatus is structurally similar to that of Figure 4. (and if the same reference numerals were used in the two Figures, to make understanding easier), except that the buttons 94 are on the side of FIG. the cover 84 in the apparatus 100. In the embodiment illustrated in Figure 5 A, the apparatus 100 is stationary and used to follow the movement of the finger 102 of an operator. It should be clear that the apparatus 100 can be flipped or used as a mouse, in a manner quite similar to the mouse of Figure 4. Figure 5B shows a perspective view of the apparatus, showing an optional switch 104 which is used to indicate if the apparatus 100 is used as a normal mouse or in the embodiment shown in Figures 5 A and 5B. Alternatively, said switch may be a gravity switch mounted in the apparatus for automatic switch modes. Generally, it is desired to know in which modality the apparatus is operating, since the direction of movement of the cursor is opposite for the two modalities and generally, the desired sensitivity is different for both modalities. Furthermore, by using the translation measurement apparatus with a small opening, as in the present invention, and moving the finger along its opening, it makes it possible to move the cursor through the translation measurement of the finger, in a very similar to a contact pad. This function can be called "point of contact" and can be used in the tiny locations dedicated on the keyboards as well. This apparatus would be identical to the apparatus of Figure 5, except that the optical chip would be mounted on the keyboard like the switches. Also, an OTM "point of contact" can be used on the top of the mouse as an alternative to a spiral wheel. The "clicks" can be detected, for example, putting the finger in cash and out of the range of the point of contact. This device can be used to replace pointing devices other than the mouse, for example, pointing devices used in laptop and palmtop computers. Virtually, any movement in one or two dimensions can be controlled using said apparatus. Currently, the pointing devices of laptop computers use either a tracking ball, a contact pad, a tracking point (nipple) or an attached mouse. These apparatuses have various disadvantages. In particular, the tracking ball collects much dust as a regular mouse, the contact pad is sensitive to obstruction and was considered unfriendly by many users, the tracking point deviates when it must be still and the attached mice are delicate and they require a desktop computer to function. The point of contact apparatus is small in size, its working aperture can be less than 1 mm2 and provides high resolution and dynamic range. This is the ideal solution as a pointing device to be embedded in a laptop computer. The device is operated by moving the finger across the face of the opening, in a manner somewhat similar to the use of the contact pad. Being the difference that the opening is of a very small size compared to the contact pad, it is free of problems such as humidity and clogging and its reliability is expected to be high. In fact, several point-of-contact devices can be easily embedded in a simple laptop or a palmtop, including on the keys, between the keys or next to the screen. Additionally, a pressure sensitive apparatus may be included below the point of contact apparatus, and the sensitivity of the contact point responds to the pressure of the finger on the point of contact.
In a preferred embodiment of the present invention, two contact points are provided, a first contact point and a circuit system which moves the pointer in response to it and a second contact point and a contact circuit which causes the spiral response of it. In a preferred additional embodiment of the present invention, the present invention can be used as an improved system for measuring the translation and / or speed for an exploratory pen, with the ability to scan lines of text (or any other pattern) and store them, to later download them to a PC and / or for conversion to ASCI I code using the OCR software. An example of such an apparatus is illustrated in Figure 6. A scanning pen 120 comprises a "read" head with a photo distribution of one or two dimensional detectors (such as a CCD distribution) 122 and a lens 123, sufficiently wide for explore a typical height of the line, and a lighting source 124 as in conventional light pens. The head of the pen contains an optical translation measurement system 82 according to the present invention, for one or two measurement axes of the translation of the head of the pen across the width of the scanned paper and possibly another to extract the information of the rotation. Then the pen can either store the scanned line as a bitmap file (suitable for manual writing, drawings, etc.) or translate it immediately to binary text using the internal OCR algorithm. For this purpose and for the power supply and control of various apparatuses in boom 120, it is provided with a controller or microprocessor 128 and batteries 129. The optical translation methods of the present invention allow the apparatuses to be of small size, convenient to use and accurate. The high accuracy results of the high inherent accuracy of the method of the present invention compared with the current times based on mechanics and the ease of measurement in two or three dimensions. Nowadays, similar commercial apparatuses use a wheel with a pattern that is pushed against the scanned surface while it is being explored and rolling in order to measure the translation by detecting the rolled angle of the wheel. This technique detects only the location along the line and not along its vertical axis and its relatively low accuracy limits the range of applications for which it can be used. A further preferred application of the optical translation method and the apparatus of the present invention is a portable or fixed apparatus for scanning signatures and retransmitting them to an authorization system. Similar in principal to the explorer pen, the signature reader contains a "read" head, with a photo distribution of one-dimensional or two-dimensional detectors (such as a CCD distribution). It has a wider opening than the explorer pen, to be able to read larger and longer signatures and it contains an optical translation measuring device, for the detection of two translation axes of the hand or the instrument which is moving in device across the scanned signature. The signature reader does not contain any OCR, since text files will not be created. Instead, it is connected (through a hard cable line or a direct wireless link, or through an off-line system), to an "authorization center", where the scanned signature is compared to a " standard signature "for validation. This device can be accurate, while it is economical, and easy to use. Yet another additional application of the apparatuses and methods described above is in the field of encoders. The present invention can replace linear encoders, which generally require high accuracy marks already on a coder wheel or on a surface, by a substantially unmarked coder. An angular encoder 130 according to this aspect of the present invention is shown in Figure 7. The encoder 130 comprises a disk having a diffusely reflective surface 132 mounted on an axis 131. It also includes an optical chip 82 and a controller 90, preferably essentially as described above. Preferably, the surface 132 is marked with one or two radial marks 136 to act as reference marks for the encoder and for the correction of errors, which may occur in reading the angle during rotation. This mark can be read by the optical chip 82 or by using a separate detector. The movement of the surface illuminated by the chip 82 can be described as a common translation combination of all the dispersers according to the tangential movement in the illuminated portion and in the rotational movement according to the angular velocity of the surface 132. Preferably, the illuminated area is small compared to the distance from the center of rotation so that the induced curvature component can be omitted. Alternatively, in an operation mode different from the Doppler, a grid with an equal angular space between the grid lines is preferably used, making it possible to directly measure the angular displacement instead of measuring the equivalent translation of the surface. A further embodiment of the present invention is a virtual pen, that is, a pen that translates the movement of the page without distinctive features into position readings. These position readings can be translated by a computer into virtual writing, which can be displayed on the screen or translated into letters and words. The computer can then store this virtual script as an ASCI I code. The transfer to the computer can be done, either online (using a cable connection or preferably a wireless connection to the computer, or offline where the code or positions are stored in the "pen" and transferred after the writing has been completed This mode of the present invention provides a compact, paperless and voiceless memory device In a typical fax / printer, the paper is moved at a constant speed relative to the writing head with a Exact motor The head releases the printed data line by line, in a way correlated with the paper feed speed.This method is both costly, since it requires an exact motor and a mechanical adjustment, as well as inaccurate, since the paper Sometimes it slides in the apparatus, so the translation of the paper is not well correlated with the printing apparatus, resulting in missing or cut lines. optical edition of translation, it is possible to detect the sliding of the paper by measuring the advance of the paper in line. The printing apparatus is then coordinated with the actual translation of the paper, thus creating a highly accurate and economical system. In a similar way, these principles can be applied to a desktop scanner, where the read head replaces the writing head. In addition, the type of the paper or other surface (eg, type of material) can be identified from the characteristics of the detector signals. The characteristics that can be used to identify the type of paper include a ratio between the reflected energy of CA and CD, the absolute energy of CA and CD, proportion of harmonies, etc. or a combination of these characteristics. In addition, the sensor can detect a discontinuity in the height of the paper, quantifying the multiple feeding situation. This discontinuity can be determined by a measurement of the axial translation, an apparent discontinuity in the measured transverse direction, or the signal loss caused by the temporal loss of coherence between the reflection and the local oscillator. Figure 8 is a schematic view of a useful motion sensor in a scanner, fax machine or printer in which movement is only in one direction. The motion detector 200 includes a source 202 which is fed to a cover 204 by an optical fiber cable 205. The output of the cable 205 is collimated by the lens 206 and illuminates a moving surface 208, through a grid 210. The light reflected from the grid 210 and the surface 208 is collected by an optical fiber cable 212, which is placed at the focal point of the lens 206. The output of the cable 212 is fed to a detector 214, for the additional process !, as described above. In a preferred embodiment of document scanning according to the present invention, the motion detector measures the relative movement of a document, preferably, without using any printing on the document, while the reading head reads the information printed from the document. A memory receives the information from the print head and stores it in the memory locations, in response to the measurement of the movement of the document. In a preferred embodiment of the printer of the present invention, the motion detector measures the movement of a sheet, to which marks are to be made and a memory transmits the commands to mark the paper, according to the information in the memory , in response to the measurement of paper movement. Either or both of the scanner or printer embodiments of the present invention can be used in a fax machine in accordance with the preferred embodiments of the present invention. The motion detectors of the present invention can also be used to measure the different movements in CDs and magnetic memories. Figure 9 is a simplified block diagram of a typical electronic circuit system 130 useful for realizing the present invention. A "main" detector photo 142 (corresponding, for example to detector 50 of Figures 3 A and 3B) receives light signals as described above. The detector detects the light and the resulting signal is preferably amplified by an amplifier 144, the bandpass filtered by a filter 146 and further amplified by an amplifier 148 to produce a "main" signal. A compensation signal is detected, for example, by the detector photo 150 (corresponding to the detector 52 of Figures 3 A and 3C) and subtracted (after the amplification, by the amplifier 152 and the filtering of the bandpass by the filter 154) of the "main" signal in a difference amplifier 155 to remove residual low frequency components in the main signal. Preferably, the bandpass filters 154 and 146 are identical. The resulting difference signal is amplified by a controlled voltage amplifier 156 whose gain is controlled by the output of a low pass filter 153 (which is attenuated by an attenuator 158 optionally adjusted during system calibration). The output of the amplifier 156 is fed to a zero crossing detector and counter 160 and the direction control logic 162, which determines the direction of translation of the surface. Where a piezoelectric element 64 is used (Figure 3B), a control signal corresponding to the frequency of displacement of the element is fed to the address control logic 162, where it is subtracted from the zero crossing count of the detector. For the preferred embodiments of the present invention, the wavelength of the laser source is preferably in the infrared, for example 1550 nanometers. A spectrum width of 2 nanometers is normal and can be achieved with diode lasers. A 5 mW power source is also typical. A grid opening of 1.5 mm by 1.5 mm and a grid period of 150 lines / mm is also typical. The output of the laser source is collimated in a normal manner to form a beam having a diameter somewhat less than 1.5 mm and is normally incident on the grid at an angle of 30 degrees from normal. The optical substrate can have any convenient thickness. However, a thickness of several mm is normal and the focal length of the lenses used is designed to provide the focus as described above. Usually, the focal length of the lenses is a few mm. Normally, the minute aperture 46 (Figures 3A to 3C) has a diameter of several micrometers, generally 10 micrometers. It should be understood that the above typical dimensions and other features are provided solely as references, and that relatively wide variations in each of these dimensions and characteristics are possible, depending on the wavelength used and other parameters of the optical chip application. .
In some preferred embodiments of the present invention, the aperture is omitted and replaced by an "effective aperture". This effective opening is achieved by focusing a local oscillator field, such as reflected or refracted light from a grid in the detector. In this way, the amplification of the reflected field from the surface is achieved only at the focus of the local oscillator field. Therefore, the minute opening 46 of Figures 3A, B and C can be removed, and the local oscillator field focused on the surface of the detector. The intensity profile of the focused local oscillator field determines the amplification of the signal fields in the same location of the detector. Therefore, where the intensity is high the amplification is significant, while the low intensity of the local oscillator results in a low amplification. The focused point of the detector surface therefore functions in the same way as a real minute aperture in a "standard" spatial filter. The quality of the spatial profile of the local oscillator beam-in the manner in which it closes, to be limiting diffraction-determines the resulting spatial filtering quality. A local oscillator field with limited diffraction focused on the detector uses the maximum amount of power for the amplification of the signal, and is not sensitive to angular misalignments as a real minute aperture. The elimination of the physical aperture in this manner results in a more robust distribution having lower sensitivity to mechanical vibrations, wide tolerances in angular alignment, and higher overall amplification. The light of the signal that is not amplified is not rejected, as is the case with the aperture, but, with a local oscillator field much stronger than the signal field, its effect on the measurement is negligible. The same distribution is also relatively insensitive to focusing errors. The use of an effective aperture distribution in Doppler measurements with a grid, in which the direction of the local oscillator field depends on the wavelength, has the advantage of not being sensitive to variations in the wavelength of the wavelength. source. A change in the wavelength causes a corresponding change in the reflection angle from the grid, so that the image of the local oscillator in the detector is moved. If a real minute aperture is used, this affects the measured amplitude of the signal, and may result in a total loss of the signal. With an effective minute aperture, the measured signal is not affected as long as the focal point is in the detector. In addition, the detector signal is independent of the wavelength in a grid-reflector configuration, and is a function of the translation, the grid period and the order of reflection of the local oscillator, as described above. with respect to grid-based systems. A preferred embodiment of a distribution wherein the focus is directly on the detector is illustrated in Figure 10. Figure 10 illustrates (for simplicity of explanation) a one-dimensional sensor without address sensing packaged in a standard electronics package (T05 or similar). The sensor includes, at least in part, a coherent radiation source such as a laser diode 250, a lens 252, the grid 254, a detector 256 (eg, a PIN diode), a cover 258, output cables 260 and electronic components 262. The laser diode 250 and the detector 256 are preferably located in the same optical plane, which is also preferably the focal plane of the lens 252. The zero order reflection of the laser from the grid 254 is reflected on the surface of detector 256 and serves as a local oscillator. If the distances of the laser diode 250 and the detector 256 from the lens are different, the distribution is made so that the laser image is focused by the lens on the surface of the detector, as described above in detail with respect to the modality, which uses a non-collimated source, and a corresponding spatial filter. Although not shown in Figure 10, address detection and in some of the successful modalities, address detection as previously described (or will be described below) can be adapted to these modalities. The operation is similar for sensors that use first-order diffraction (or higher) as the local oscillator field. The distribution is slightly different. One of said distributions, according to a preferred embodiment of the present invention, is illustrated in Figures 11 A and 11 B. The illustrated sensor is a two-dimensional sensor without direction detection, and includes a radiation source, such as a laser diode 270, a lens 272, a two-dimensional grid 274, a pair of detectors 276 and 278, a cover 280, output cables 282 and the electronic components 284. As in the embodiment of Figure 10, the diode laser 270 and detectors 276 and 278 are preferably in the same optical plane. Figure 11 B shows a planar view of the plane of detectors 276 and 278 and source 270, as seen in section XIB-XIB. The detector 276 functions as an X-axis detector and the detector 278 as a Y-axis detector. The first-order diffraction from the grid 274 in the X direction is focused on the X 276 detector, while the first-order diffraction the Y direction is focused on the Y detector 278. Preferred embodiments of the present invention using an effective minute aperture are easier to align and, when manufactured as an integrated optical block, have less severe tolerance requirements. This is especially true when the local oscillator is derived from the diffracted light from a grid in a non-zero order because, for this case, the placement of the minute aperture depends on the wavelength. Therefore, the stability of the wavelength of the illumination source is much more relaxed when an effective aperture is used, instead of a physical aperture. In some preferred embodiments of the present invention, alternative methods of determining the direction of movement are used. In the preferred embodiments of the present invention, which provide these alternative methods, a mechanical movement of an optical part is used to determine the direction of movement. In some preferred embodiments of the present invention two detectors are provided and movement in one direction causes illumination of one of the detectors by reflected or refracted light from the grid. Two preferred embodiments of the present invention, which provide direction detection using this principle, are illustrated in Figures 12A-12B and 13A-13B. Figures 12A and 12B illustrate the principle of one of these modalities. These Figures illustrate a sensor 290 that includes a source of at least partially coherent radiation, such as a laser diode 292, a lens 294, a detector 296, a second detector 298 and a pair of grids 300 and 302. The grids 300 and 302 are mounted on the surface of a co-located bi-stable element 304. The movement of the sensor in one direction causes the element 304 to take the position illustrated in Figure 12A, so that the radiation is reflected or refracted from the grid 300 to detector 296. The friction of element 304 with the surface whose movement is being measured, when the sensor is moved in the other direction, rotates element 304 to the position illustrated in Figure 12B. In this configuration, the radiation reflected or refracted from the grid 302 to the detector 298. The direction of the movement, therefore, is determined from the detector from which a signal is produced. An extension of this two-dimensional operation mode is provided by replacing the 304 element with a 4-sided operation pyramid in a similar manner, with 4 corresponding detectors, where the grids are of two dimensions. Figures 13A and 13B illustrate a second embodiment of a mechanical direction detection method, using two adjacent grids. In a similar manner as in Figures 12A and 12B, the embodiment comprises a source of at least partially coherent radiation, such as a laser diode 292, a lens 294, the detectors 296 and 298. The embodiment also includes two gratings 310 and 312. Each of the grids 310 and 312 has two parts with different periodicity, for example 150 Ip / mm in their left halves and 170 Ip / mm in their right halves. The bottom grid is changed by the friction of the surface 42, and moves to a previously defined stop in the direction of movement. The two halves of the grids are arranged so that the movement will cause one half of the grid to be blocked (for example, the reflecting portion of one of the grids covers the openings of the other), while the grid of the other half it will become visible (for example, it matches the metal portions), although not usually with a 50% duty cycle. The movement in the opposite direction interchanges the role of the two halves of the grids, thus making possible a difference in the angles of reflection between the two directions and the illumination of the different detectors. The two configurations are illustrated in Figures 13A and 13B, respectively. The direction of movement is determined from the detector from which it produces a signal. Figures 13C and 13D illustrate another system of changing from one grid to the other. In these Figures, only the grids themselves are illustrated. The upper portion comprising the reflection elements 400 does not move with respect to the detector. A lower portion comprises alternate portions 401 and 402 which are grids having different periods. In the position illustrated in Figure 13C the elements 400 block the grid sections 401, so that the incident light in the grids is directed to an angle, determined by the grid section period 402, which is visible to the radiation incident, and which transmits it partially. In a second position, to which the lower portion is moved by means of friction with the surface, whose speed is being measured, the elements 400 block the grid sections 402 and expose the sections 401 so that the incident light is directed at an angle that depends on the period of the grid 401. This allows the change of the detectors, which receive the light, as in Figures 13A and 13B. The principle of this embodiment of the present invention can be extended to two dimensions by replacing the grids with two-dimensional grids divided into fourths based on the same principle illustrated in Figures 13A and 13B. Figure 14 illustrates the principle of another mode of a Doppler-based sensor system for measuring the velocity of a surface. Unlike the sensors described above, this sensor does not require the use of a grid. A light source, at least partially coherent, collimated 320 illuminates an optical element 322 having a first plane 324 adjacent to and oriented towards an angle to the surface 42 and a second plane 325 parallel to the surface 42. The light reflected from the plane 324 (which is preferably covered by reflection), is focused by a lens 326 on a detector 328 and serves as a local oscillator. Part of the light reflected by the surface 42 is also focused on the detector 328, and interferes in a manner consistent with the local oscillator field. The light reflected from the surface 42 towards the detector 328 is changed in Doppler by the translation of the surface. In this way, the signal of a detector includes an oscillating component indicating the translation of the surface 42. It should be noted that the surface 325 does not play a role in the detection process. further, it should also be noted that all the components can be mounted on the optical element 322 to form an integrated sensor. The extension to measurements of two dimensions is achieved using two bifurcated planes and two detectors. According to some preferred embodiments of the present invention, the reflector from which the local oscillator field is reflected is not adjacent to the surface whose speed is being measured. Two preferred embodiments of the present invention, which incorporate similar principles, are illustrated in Figures 15 and 16. Figure 15 illustrates a sensor that includes a light source, at least partially coherent, such as a laser 350, a medium optical 352 having partially reflecting and partly transmitting surfaces 354 and a fully reflective surface 356. The sensor also preferably includes a lens 358 which collimates the source 350 and a spatial filter incorporated in this embodiment by a lens 360 which focuses the light in the detector 362 and the electronic elements processing the signal 364. The focused light acts as an effective minute aperture, as described above. The light source provides a radiation, at least partially coherent, which is directed towards the surface 42.
The light from the source is split by the surface 354 in a ray reflected from the surface 352 to the surface 356 and a beam transmitted to the surface 42. The light that is reflected from the surface 42 is transmitted through the surface 354. , towards the detector 362. The light that is reflected from the surface 354 is completely reflected from the surface 356, so that a third reflection thereof from the surface 354 is also directed towards the detector 362. The difference in the length of optical path for the propagation of light in the medium by multiple reflections (local oscillator) and the light reflected from the surface 42 towards the detector must be within the coherence length of the source. The translation of the surface is the result of an oscillating signal of the detector indicating the amount of translation as described in the previous modalities. In the preferred alternative embodiments of the present invention, the surface 354 may be a grid where the local oscillator is derived from the light diffracted therefrom to one of its diffraction orders. Because of this situation, the surface 354 need not be at an angle to the surface 42. Although the surface 356 is preferably fully reflective, it may be partially transmissive or partially absorbent. This reduces the total signal of the oscillator. If the surface 356 is partially transmitting, the light passing through it can be used to measure the intensity of the light source using another detector, and subsequently compensates for the modulation of the amplitude of the intensity of the source in order to improve the operation at the lower end of the speed range as described above in conjunction with Figures 3A and 3B. According to a preferred embodiment of the present invention, the region between the surface 354 and the surface 42 is filled with a second optical means to improve the flattening of the surface 42 (if it is not rigid, for example a paper) and to avoid the accumulation of dirt. According to another preferred embodiment of the present invention illustrated in Figure 16, a sensor is manufactured using a modified cubic-ray beam separator. And preferably collimated at the at least partially coherent light source, such as a laser 380 which is directed towards a partially reflecting, partially transmitting surface 382. The light transmitted through the surface 382 is directed towards the surface 42 and from the surface 42 is (partially) reflected from surface 382 to detector 384 (by means of focus optics 386). The light reflected by the surface 382 is directed towards a reflector 388 and from there (through the surface 382) to the detector 384. In this way, the beam separator acts as an interferometer so that a translation of the surface 42 into In relation to the apparatus and parallel to the surface, it introduces a Doppler shift between the reflection of the reflector 388 (which serves as a local oscillator) and the reflection of the surface 42.
In this way, the light that is reflected from the surface 42 and the light that is reflected from the reflector 388 interfere with the detector 384. The optical medium is scaled such that the optical path length difference of these two light waves , is within the coherence length of the source 380. The distribution is made in such a way that the partially reflecting interface, the fully reflecting interface and the surface are not parallel to one another. In this way, the detector signal includes an oscillating component due to the Doppler phase shift of the light reflected from the surface, which is representative of the translation of the surface in relation to the optical apparatus and parallel to the surface. Preferably, the light from source 380 is collimated. Preferably, the light reaching the detector 384 is focused on the surface of the detector so that an image-point of the source 380 is formed therein. Two-dimensional translation measurements can be achieved using orthogonally, partially reflecting, orthogonally reflecting surfaces or orthogonal inclinations. The Doppler shift of the light that is reflected from the surface 42 is proportional to the relative velocity component between the sensor and the surface 42 along the bisector between the incident light beam on the surface and the portion of light reflected from the surface. same that is collected by the detector. The Doppler shift is inversely proportional to the wavelength of the light. Preferably, the optical means is selected such that the scattering of the diffraction index induces a change in the bisecting angle with respect to the plane of the surface that compensates for the effect of the change in wavelength on the Doppler shift. In this way, the measurement error due to the finite width of the source spectrum and the deviation of the wavelength is substantially reduced. The method illustrated in Figures 15 and 16 and its embodiments provides a relatively inexpensive, robust, free alignment and accurate translation measurement apparatus of rough surfaces that move parallel to the surface. The method is applicable to a wide range of applications that use translation measurement, as described with respect to other embodiments of the present invention. Figure 17 illustrates another preferred embodiment of the present invention. The modality of Figure 17 provides the implementation of a specific polarization in the reflection from the surface. Figure 3C illustrates a method for determining the direction by providing a different polarization for the reflected light from the surface 42 and the local oscillator. A phase change is provided by placing a birefringent plate in the path of radiation to and from the surface. However, this method is based on the assumption that when light is reflected from the surface, its polarization is preserved. Frequently this is not the case, and the quadrature signal that is supposed to be generated by the detectors deteriorates, and can still change the signal for the same direction of movement. An additional linear polarizer between the birefringent material ("quarter-wave plate"), and the surface makes it possible for the measurement to be insensitive to the characteristics of the surface. The polarizer Implants its linear direction of polarization in the reflection from the surface, independently of the characteristics of the same. Placing the axis of the polarizer at 45 degrees to the axis of the birefringent material, the reflection is subsequently polarized in a circular manner through the birefringent layer as it passes through it to the detectors. In this way, the precise quadrature signal is ensured for the two polarized detectors even when the surface itself is not preserving the polarization. Another property of this distribution is the ability to place the birefringent layer "on the top" of the grid (instead of between the grid and the surface). The local oscillator light undergoes a double phase change (by the quarter-wave plate, and a half-wave retardation is seen) while the reflection of the surface is changed only once and this makes possible the measurement of the square. Figure 17 illustrates a first preferred embodiment of motion detector 500 that includes this feature. The motion detector 500 comprises a partially coherent light source 502 which illuminates a preferably collimator lens 504. The light emerging below the lens 504 is preferably collimated (e.g., all light rays are parallel). A quarter-wave birefringent plate 506 and a grid 508 lie in the plane. The light reflected / diffracted from the grid undergoes a 180 degree phase change between its orthogonal components because it is passing through the birefringent plate twice. Although the plate 506 and the grid 508 are illustrated as separate elements, these can be combined in a single element, for example by depositing or engraving the grid on the surface of the birefringent plate. A linear polarizer 510 is preferably located below the grid. The light that is reflected from the surface (not illustrated) below the polarizer that passes through the birefringent plate for a second time, can be polarized in a circular manner. However, as the light passes through the polarizer 510 for a second time before reaching the plate 506, the polarization is implemented, and the "contamination" of the measurement is avoided. The light diffracted from the grid at an angle determined by the spacing line of the grid and the diffraction order and the light reflected diffusely from the surface are incident on a detection module 512. The detection module 512 includes a phase grid. 514 which separates the incident radiation preferably into two equal parts and sends them by means of a pair of polarizers 516 and 518 to a pair of detectors 520 and 522, respectively. The polarizers 516 and 518 are aligned at 90 degrees with respect to each other and are aligned to provide preferably equal resistance of the diffracted radiation of the grid to each of the detectors. The detection module 512 performs the same function as the elements of Figure 3C. That is, the detection module 512 separates the circularly polarized wave (based on the reflection of the surface) into linear components and each of them interferes separately with a portion of the wave diffracted by the grid 508. The diffracted wave, which has a linear polarization at 45 degrees to the direction of polarization of each of the polarizers, is also separated by the grid and detected, preferably and equally, by the detectors. The magnitude of the movement is determined conveniently, from the number of zero crosses of the signals detected by the detectors (based on a Doppler shift), and the direction of movement is determined based on the relative phases of these signals. The detection module 512 uses a phase grid and two polarizers to separate and direct the incoming waves to the detectors, instead of the polarizing beam separator of Figure 3C. In practice, it is considered that the production of the incorporation of module 512 is less expensive. If a binary phase grid (or a marked grid) is used, then the system is not only inexpensive, but also inefficient.
In a preferred embodiment of the present invention, the module 512 is mounted on a back plate or a heat-sealed substrate 524, together with the source 502 and the electronic component module 526. The electronic component module 526 may contain a controller for controlling the source 502 and electronic components that receive the signals from the detectors 520 and 522. Preferably, the electronic component module 526 partially or fully processes the signals, as described above, to provide information to a computer or an apparatus ( not shown) with respect to the magnitude and direction of the movement of the surface. Figure 18 illustrates another motion detector 530 which is generally similar in structure to that of Figure 17. However, the detector includes a number of features that must be observed. For ease of description, those parts of the detector 530 that are similar to those of the detector 500 of Figure 17 are marked with the same reference numbers and do not have an additional description. In Figure 18, the local oscillator is spatially separated from the illumination of the surface and the diffraction path. In addition, in Figure 18, a cut-off 532 is preferably provided to equalize the wavelength lengths for the waves diffracted from the grid and reflected from the surface, whose relative motion is to be measured. As will be remembered, it is preferred that the coherence between these waves is not required in the detectors. Since the path of the wave reflected from the surface is longer than that of the grid, this requires a strong coherence at the source 502. In a preferred embodiment of the present invention, the cut 532 provides a reduction in the length of optical path for the wave reflected from the surface, such as to coincide with the path lengths. The optical distribution of the separate local oscillator such as that shown in Figure 18 is also intrinsically adequate to have only one transmitted beam and no diffraction of the illumination of the reflected surface, desired in the Doppler operation mode. However, the separation of the beam serves on the one hand as a local oscillator and, on the other hand, serves to illuminate the surface that is more sensitive to the beam quality, and less robust than the schemes that use most or all of the Lighting, both for the local oscillator and for surface lighting. Although this cut may be useful for other preferred embodiments of the present invention, for example for the embodiment illustrated in Figure 17, it is especially useful, when a scratch resistant substrate or layer is provided, preferably a shield 534 adjacent to the surface. This substrate increases the optical path length of the reflected wave from the surface, without changing the length of the optical path of the diffracted wave from the grid. The provision of a protective layer is also applicable to many of the embodiments described above. In addition, the substrate 534 or other parts of the optical path can be colored (e.g., by spectral filtering) to reduce the effects of scattered light while passing the laser light. In the embodiment illustrated in Figure 18, the structure for generating the reflected and diffracted waves is different from the structure illustrated in Figure 17. In Figure 18, the phase grid 536 is on top of a birefringent plate of 1/8 wave 538, which in turn, is located below reflector 540. Preferably, the reflector is applied directly on plate 538. As the waves that are reflected from reflector 540 pass through the plate a 1/8 of wave twice, the reflected wave is polarized in a circular manner. The reflection from the surface preferably passes through a linear polarizer 542 in both directions, as it is reflected from the surface. In this way, the wave has a linear polarization implemented. The operation of the rest of the system is the same as that described for Figure 17. In the preferred alternative embodiments of the present invention, a quarter-wave birefringent layer can be placed in the ray path emitted by the source 502, converting it in a circular polarization. In this way, this layer can be much smaller (and less expensive) than the comparable layer illustrated in Figures 17 and 18, which layers are then omitted. In addition, for those embodiments of the present invention in which a birefringent plate is used, a plate that results in an elliptical polarization (instead of the circular polarization described above) can be used. In some preferred embodiments of the present invention, a quarter-wave layer (of birefringent material such as quartz) can be deposited on the emitting surface of a linearly polarized laser diode in another manner, to produce a circularly polarized beam. Preferably, the deposition is part of the process by which the diode is manufactured, for example, the birefringent layer is deposited on the top of an External Distributed Bragg Reflector of a Vertical Cavity Emitting Surface Laser. This scheme uses much smaller amounts of birefringent material, since the covered area is only the area of the emitter. In addition, a small birefringent layer can be manufactured more accurately than a large one. An additional linear polarizer deposited below the birefringent layer forms an optical insulator combination, attenuating the reflection of scattered light back into the laser cavity. Similarly, in some preferred embodiments of the present invention, linear polarizers are incorporated within the surface of the detectors, rather than providing separate polarizers, when it is indicated that they are being required in some of the embodiments herein. Invention referred to above. The use of said polarized detectors reduces the complexity of the assembly of the motion detectors. The application of a polymer-based polarizer at the top of the detector can be used to produce said detectors. Alternatively, the polarizer can be manufactured by a thin-line slot (with line widths in the order of a wavelength) of a dielectric layer deposited on the face of the detector. Figures 19A and 19B illustrate two integrated versions of motion detectors based on direction detection principles similar to those of Figures 3C, 17 and 18. Figure 19A illustrates a motion detector 550 constructed on a batch 552 comprising a light separator 554 and two lenses 556 and 558. A laser diode source 560 is mounted adjacent the lens 556, which combines the light emitted by the source. The collimated beam 561 collides in the light separator 554, which divides the beam into a first part 562, which continues to the surface 12, and a second part 564 which is reflected to a 1/8 wave 566 plate. and a mirror 568. The beam 564, after passing twice through the plate is circularly polarized, as it travels back to the beam spacer 554. The beam 562 passes through a linear polarizer 570, and preferably through a protective layer 572 before being reflected back to the ray separator 554. The portion of the reflected beam 564 passing through the beam separator and the portion of the reflected beam 562 reflected from the beam separator are directed together towards the 558 lens, which focuses on them. A second light separator 574 separates both rays and directs them to the polarized detectors 576 and 578 (each having a polarizer 580 and a detector 582). The detectors are used to detect the frequency and relative phase of the linear components of the reflected beam from the surface 12, essentially in the same manner as described above with respect to Figures 3C, 17 and 18. It should be noted, that the upper part of the motion detector 550 is not square with the background so that the reflected beam is changed Doppler from the incident ray in surface 12. This Doppler shift (and its sign) is used to detect movement. In addition, in the preferred embodiments of the present invention the lenses are covered against reflections to avoid the effects of multiple reflections. A second integrated motion detector 590, illustrated in Figure 19B, also incorporates similar principles. All the optical components of the system are mounted in a block 592, in which a grid 594 is walled. Preferably, the grid and the upper and lower surfaces are parallel. Two lenses 596 and 598 that have functions similar to those of the lenses 556 and 558 of Figure 19A are preferably incorporated within the block 592. In Figure 19B, elements that have functions similar to those of the corresponding elements of Figure 19 have similar numbers. A reference beam reflected from the grid 594 towards the 1/8 wave plate back to the mirror (566, 568) and from there, by means of a second reflection towards the lens 598. The ray passing through the grid, preferably passes through the linear polarizer and the optional protective layer, and is reflected to the lens 598. The detection system operates in a manner similar to that described above. Figures 19C and 19D illustrate details of a detector module 610 for a system in which a birefringent plate is used to affect one or both of the gratings or rays reflected on the surface. Examples of such systems are the motion detectors described in Figures 17, 18 and 19A. In these motion detectors, when the source is linearly polarized, the birefringent plate can be moved close to the detectors. In this case, the birefringent plate would be smaller when placed elsewhere and may, in some preferred embodiments of the present invention, be integrated with the detectors as described above for the polarizers. For these modalities, a polarizer is placed (for example, near the surface to be measured) so that only a light passing to and from the surface passes through it. The polarization axis of the polarizer is placed at a 45 degree angle to the polarization of the light from the source, so that the surface light has a polarization that is at a 45 degree angle from the local oscillator's light.
In this situation, the detector module 610 as illustrated in Figures 19C and 19D can be advantageously employed in place of the module 512 of Figures 17 and 18 and, in a modified form, using the same detection principle, for module 576 of Figure 19A. The elements, in Figures 19C and 19D, which have the same function in the corresponding elements of Figures 17 and 18 have the same reference numbers as the elements of Figures 17 and 18. The module 610 is similar to the module 512, except that the quarter-wave plate 612 is placed in front of the polarizers 516 and 518. The orientation of the polarization of the quarter-wave plates, the polarizer and the incident light are illustrated in Figure 19D, which is a sectional view from below along lines DD in Figure 19C. The axis of the polarizers is indicated by the reference numerals 614, 616 and the polarization axis of the quarter-wave plate is indicated by the reference number 618. The linearly polarized light which is incident on the plate of a quarter wave 612 along one of its axes passes through the plate without changing its polarization. The linearly polarized light that has its polarization at 45 degrees to the axis 618 is transformed into a circularly polarized light. The reference numbers 620, 626 indicate the polarizations of the incident grid and the waves reflected on the surface, where it is not important which of the two waves is polarized in the direction 620 and which is polarized in the direction 626.
In addition, one of the waves may be polarized in a direction 626 ', instead of 626. In operation, the Incident wave having the polarization 620 is transformed into a circularly polarized wave. This circularly polarized wave is separated into two equal components by the polarizers 516 and 518 so that two linearly polarized waves of equal amplitude are incident on the detectors 520 and 522. However, these two waves are 90 degrees outside the phase of time (as well as they have orthogonal polarizations). The wave having 626 or 626 'polarization passes through the quarter-wave plate without polarization change. This is also divided into two waves that have perpendicular polarization. However, these waves are in time phase. Therefore, each detector will detect the interference between the light waves, which originate the two signals that are 90 degrees outside the time phase. This difference in phase can then be used to determine the direction as a standard detection of the quadrature. If the birefringent plate 612 is omitted, then either the reflection of the surface or the local oscillator field is selectively blocked by one of the detector polarizers, depending on the polarization directions of the local oscillator and the reflected illumination of the surface. If for example, the polarization direction of the source is 620, then it will be blocked by the polarizer referred to by 616. In this way, only the illumination of the reflected surface will be detected by the detector corresponding to the component Et2. Alternatively, if the polarization of the reflected surface is 620, then the detector associated with the polarization direction 616 will detect only the local oscillator field, thereby making it possible to compensate for the component E02. The output of a detector used for the compensation of the component Eo2 can be used as a reference voltage and subtracted from the output voltage of other detectors used for the translation movement. This forms a detection mode of the "differential" type. For example, said subtraction may be performed at the output of the trans-impedance amplifier step, thereby eliminating most of the DC voltage from the detected signal. Alternatively, you can use a scheme that uses a high pass filtering to remove the DC voltage, such as the one described in Figure 9. Preferably, the bandwidth of the compensation signal is limited according to the bandwidth of the source noise. Otherwise, other uncorrelated noises (for example, thermal noise) are added in a really unnecessary way by subtracting the compensation signal. Compensation of the Eo2 component is essentially useful, if the source is switched off and on repeatedly (for example, when operating in the 'sleeping mode' to save energy and for eye safety). A modulated source complicates the removal of DC voltage with a high pass, as described in Figure 9, but this is reduced or eliminated without using a high pass, in the compensation of the Eo2 component. Alternatively, changing the source can be done even without Eo2 compensation if the capacitors in the high pass are isolated when the source is turned off (thus maintaining its charge until the source is turned on again). Still another use of the measurement of the component E02 is a feedback in a current source control circuit. This is especially important in order to control the optical power of the source, if a significant variability of the energy is expected (for example, due to a large operating temperature range). The distribution of Figures 19C and 19D without the birefringent plate 612 may be useful when a vertical cavity surface emitting laser (VCSEL) is used as the light source. When operated in a correct manner, certain VCSEL diodes can have one of two possible orthogonal polarizations, where at any given moment, the polarization of illumination is aligned with one of the polarizations. In this way, there is an ambiguity with regard to the direction of polarization. This poses a problem in the use of the VCSEL, where direction detection is important, since the two polarization directions result in an opposite phase difference of the crossed polarized detector pairs for a given direction of motion.
According to the configuration presented in Figure 19D, and assuming that the polarization direction of the source is along 620 or orthogonal to 620 (not shown). Then, if the birefringent plate 612 is removed, the polarizer 614, for example, will block or transmit the illumination of the local oscillator. In this way, the output of the detector 522 will be either high or low, depending on the polarization direction of the source, and the output of the detector can be used to control the conversion between the relative phase of the signal and the direction of the movement (for example, as a signal that designates the day sign zero crossing account). It is sufficient to use one of said polarized detectors (with high or low output, depending on the direction of polarization) in addition to the detectors used to detect the movement. However, if two detectors (522 and 520) are used then, in each polarization direction one of the detectors will have a high output, while the other will measure the illumination of the reflected surface and can be used for compensation of the component.
In the previous scheme, additional detectors are used to solve the polarization ambiguity of a VCSEL. Alternatively, the VCSEL can be rotated slightly with respect to its 'optimal' polarization direction. Assuming that the 'optimal' direction of the VCSEL polarization so that the preferred polarizations are a or a + p / 2, then the ratio R P between the DC voltages of the detector pairs is: tan (a): one polarization
cot (a): another polarization
Thus, the optimal alignment of the VCSEL is a = p / 4 (along 626, for example), the CD component detected by the detectors in a crossed polarized pair such as that described in the Figure 19D will be the same, regardless of the polarization direction of the VCSEL. p However, if the radiants a = - + ß, then R P = 1 + 2 ß in a 4
polarization and R P = 1 - 2 ß if the VCSEL output is in the other polarization. In this way, R P > 1 when the VCSEL emits in one polarization and the R P is less than one for the other polarization. Therefore, if the VCSEL is rotated with respect to the 'optimal' orientation, the result of a comparison between the DC voltage of the detectors in a pair of detectors used for the measurement of the translation indicates the direction of the polarization without the need for additional detectors dedicated for that purpose. Yet another way to resolve a possible polarization ambiguity of the local oscillator is to use a linear polarizer in the optical path between the source and the grid, with the polarizing axis at 45 degrees from any of the orthogonal polarization directions. Thus, for example, the polarizer is placed along 620 when the polarization of the VCSEL is either 626 or 626 '. Alternatively, the polarizer is placed along 626 if the polarization of the VCSEL is either along 614 or along 616. This forces the polarization of the source to be the same as that of the polarizer at the expense of the loss of approximately one half of the optical power. Parallel low-frequency noise (such as the Et2 and Eo2 components and power line interference) superimposed on the higher frequency signal can affect the quadrature detection of the high frequency line for the following reasons: • The zero crossing effects of the high frequency signal have been lost. • The order in which the zero crossing events happened is changed, therefore the detection of the direction of the quadrature detector is changed. • Zero crossing events of low frequency noise are counted and added to the measurement. One of several methods (or combination of methods) can be used to solve possible low frequency modulations by means of signal processing (in addition to, or in place of the optical schemes described above), according to several preferred embodiments of the present invention: • Assume that P and Q are the output signals of a pair of detectors such as detectors 520 and 522 of Figure 19C. . P and Q are ideally identical other than the temporary phase difference of +90 degrees or -90 degrees, depending on the direction of movement, and the addition of noise. In addition, also the signals D = P-Q and S = P + Q are derived from signals P and Q. Then, the signal D has the elimination property of all noise sources that are common to both P and Q.
In addition D and S have temporary phase differences of 90 degrees. Therefore, D and S are equivalent to P and Q when there is no noise, but if the common noise sources are significant, the zero crossings D measure exactly, the translation while the zero crossings of S can be used to help in determining the direction of movement. In addition, the elimination of common noise is not restricted to low frequencies. • The amplified signal can be divided into two (or more) frequency ranges. The selection of the appropriate channel may be based on the measured frequency. • The use of a band gives an adaptive step, controlled by the frequency of the signal and with the capacity to adapt to changes in frequencies resulting from the possible acceleration of the surface in relation to the OTM component. The bandpass adapter also reduces other sources of noise, such as thermal noise and 1 / F noise. This can be increased, for example, by using voltage capacitors controlling the high pass and elements in the low pass.
• The use of the highest amplification of the high frequency signals, such as the resulting amplitude of the high frequency signals, is higher than the low frequency ones, and therefore, the count of the zero crossings of high frequency it is only mildly affected. A preferred embodiment of the adapted bandpass circuit 899 for rejecting frequency noise in the presence of a high frequency signal is presented in Figure 27. The zero crossing detector 900 converts an analog signal into an input 910 to a logic signal at an output 920. When the signal is at low frequency (e.g., 50Hz), transistors 931 and 932 are not driving most of the time and a capacitor 940 is charged through a resistor 945 with a constant of Long time (0.1 sec), suitable for detecting the low frequency signal. On the other hand, when the zero crossing range is high (above a few hundred Hertz), a high pass circuit 950 conducts the current through the bases of the transistors 931 and 932, so that the capacitor 940 is charged through a 960 resistor, with a time constant as low as 0.1 msec. Therefore, the threshold of the positive input of an operation amplifier 970 follows the low frequency noise and thus rejects its detection, and the output of the operation amplifier is determined by the high frequency signal. A capacitor 980 is used to suppress the spontaneous oscillations of the operation amplifier 970. It should be noted that FIG. 27 represents a typical implementation of this aspect of the present invention, and that the zero crossing detector adapter can be implemented in several ways and using other components (for example, FET transistors, different resistors, and capacitor values and a different operating amplifier). The measurement of the quadrature movement depends on the measurement of two identical signals, which have a constant phase change between them. The magnitude of the movement is detected by the number of zero crosses in a given interval. The direction of movement is determined by comparing the zero crossing sign on one channel (for example, 'low to high' or 'high to low') to the sign of the signal on the other channel ('high' or 'low') ). Noise in the quadrature signal can result in an additional zero crossing count. If two zero crosses of one signal occur while the other signal does not change the sign, their addresses are opposite, and they are added to zero. However, if a zero crossing in a signal is changed in time, the order in which zero crossing occurs in both channels, can be reversed and result in direction detection errors in both channels, which are added to a Net count error. Errors due to reversed zero crossing events can be corrected, according to some preferred embodiments of the present invention, using 'majority vocation' in some interval. It is assumed that the direction of movement has not changed within each interval (or 'elements'). This means that the resolution is compromised by the improved accuracy. Conveniently, the zero crossing count process is performed on contingent elements. Each element starts at the end of the previous element and ends when a previously defined number of zero crossing events or more has happened on both quadrature channels. Then, the address of all the elements is determined according to the majority of address determinations (in both channels or only in one of them) in that element. In addition, each element represents a fixed number of accounts, regardless of the number of real accounts in both channels (therefore, the resolution is degraded by the duplication of the number of minimum counts in the element). Conveniently, an element of size 3 or 4 can be used. The requirement that the count of both channels be equal to or exceed the minimum number of an element is intended to avoid high frequency noise in a channel coming from take the majority vote. In an optical translation measurement of many of the types described above, according to some preferred embodiments of the present invention, the DC voltage detector resulting from the energy of the local oscillator is conveniently removed using a high pass. at the output of a first amplification stage before further amplification of the AC signal. Therefore, the high-pass cutoff of the frequency determines the measurable minimum speed.
When optical translation measurement is used for an input device (such as a mouse or other pointing device), the low speed limitation may be an important factor for the user, for example, when the user slows down movement, and approximate the specific position on the screen. In order to make it possible for the user to decrease the movement of the cursor, so that it can be placed with high accuracy on the screen, a moderate high pass filter (instead of an exact one) can be used. Using an amplification slope that gradually decreases with frequency, will result in a zero crossing closure lost for filter cut. This will effectively reduce the measured speed as the speed approaches the lower limit set by the filter. In this way, the cursor speed is gradually reduced to zero while the OTM is still within the measurement bandwidth (and still in motion). This 'deceleration' mechanism can also be applied in the software, or as part of the signal analysis immediately after the zero crossing detection, by measuring the counting rate (for example, speed) and by reducing the speed of the cursor when the counting rate approaches the lower limit of the filter. In a preferred embodiment of the present invention, the counting frequency is equivalent to a movement less than about 0.5 mm / sec. In a preferred embodiment of the present invention, the high pass filter has a slope, below the cutoff frequency of less than about 20 db / octave. Figure 23 illustrates an ideal curve 750 of the cursor speed as a function of the speed of the apparatus. Figure 23 also illustrates a curve 752 of the cursor speed as a function of the speed of the apparatus, in accordance with a preferred embodiment of the present invention. A curve 754 is also illustrated which could be the result if a relatively accurate high-pass filter were used. As will be understood, curve 754 results in a lack of virtual system capacity to move the cursor at a slow speed. On the other hand, the ideal curve can not be achieved, because zero or low frequencies must be excluded. However, the gradual transition of the curve 752 allows an exact positioning of the cursor, using a non-linear transfer function. In an exemplary apparatus, curve 752 could be linearly descending to some value, such as, for example, 1 mm / sec to cause the lack of movement of the cursor for lower hand (appliance) speeds of one third to one. half the linear minimum speed. Of course, you could use a different curve that has an even more regular transition.
The accuracy of the optical translation measurements as described above depends on the number of grid lines in the illumination beam. Therefore, for surfaces of high curvature, a flat optical configuration can not be sufficiently accurate. An example of such an application is the measurement of the rotation of an arrow 600, as illustrated in FIGS. 20A and 20B, wherein the radius of the axis may be small. For the measurement of shaft rotation, an apparatus can be placed along the axis (on one side of it). To accommodate the curvature of the shaft and make it possible to measure small diameter axes, a special optical apparatus 602 can be used as the front end of the apparatus component. The shape of the optical apparatus is illustrated schematically in Figures 20A and B. The diameter of the optical apparatus is matched to the diameter of the shaft, and the surface of the optical apparatus is designed with a grid of one dimension 604 whose lines are parallel to the shaft axis. A light source 606 is directed to focus the center of the axis, so that its phase is constant throughout the grid. Preferably, the measurement is of the type of order 0. A detector 608 detects the light reflected from the surface of the axis and the light reflected from the grid. Note that, preferably, the source and the detector are in a circumferential position with respect to the axis but are offset axially from one another, as illustrated more clearly in Figure 20B. The optical apparatus of the front end can be changed for the different shaft diameters, and allows for high resolution measurement, looking at a substantial portion of the circumference of the shaft. The detection of the direction can be obtained using an asymmetric grid or by means of another portion of the light that will be focused on the surface of the axis and the direction detected by the orthogonal polarization method described above, or by other means (e.g. observing the polarity of the driving current of the motor). An advantage of using the distribution of Figures 19A or 19B is found in the equalization of the local oscillator path length and the scattered radiation, while the same ray portions are used for both. Movement parallel to a rough surface can also induce unexpected Z-axis movement (up and down). The movement of the Z axis induces the Doppler shift of the reflected radiation from the surface, and in general, the phase of the radiation will change in response to a combination of the Z and X or Y velocities. One way to decouple the relative contributions is to use the measurements in both diffraction orders +1 and -1 (or other symmetric orders, such as ± 2, ± 3, etc.) for each of the X and Y axes. Looking at the geometry of the Incident wave perpendicular to the surface measurement, the velocities vx and vz, the wavelength of the light source?, the spacing of the grid line A, the Doppler frequency shift for the combined movement X and Z, as measured in the order +1, is:? + = (2p /?) (Vx sin (f) - vz (1 + cos (f))), where sin (f) =? / ?. A measurement in the order -1 results in a change
Doppler of:?. = (2p /?) (- vx sin (f) - vz (1 + cos (f))). We can appreciate, that the oscillating signal in the difference of the two frequencies will have:? + -?. = (4p /?) Vx, while the results of the sum of the frequency in? + +? = (4p /?) Vz (1 + cos (f)). Taking the two quadrature signals for the two orders we will have the following signals: A + = cos (? + T + F +), B + = sin (? + T + F +), A "= cos (?. T + F-), B "= sin (? _ T + F-). Using the rules of sum of sine and cosine, we can form combinations that will oscillate both in the sum or difference frequencies, and will maintain the quadrature relations: C "= B + A" - A + B- = sin (? + T-? .t + F + -F_), D "= A + A" + B + B "= cos (? + t -? t + F + -F-), C + = B + A" + A + B "= sin (? + t + ? + F + F-), D + = A + A "- B + B" = cos (? + t +? t + F ++ F.) The resulting signal C ", D", therefore has been decoupled from the relative contributions and eliminated the spurious contribution of the Z axis, to the measurement of the X axis. Additionally, the + component can be used specifically only for the measurement of the Z axis, for example, for contact detection or 'click At a point of contact, without zero-order diffraction measurement, when the Z-axis velocity is relatively high, each of the XY measurements can generally also be used as a raw estimate for the Z-axis translation. this mode, the characteristics 'down and up' of the opera Clicking on a finger can be detected. Also, it is possible to detect the operation of the 'Click' using the deceleration and abrupt acceleration of the finger when touching and separating it from the point of contact, respectively. For the latter, only the absolute speed of the Z axis (or its derivative) is used. Another methodology for the determination of the translation of the Z axis and the exact determination of the transverse movement is illustrated with the help of Figure 21. Figure 21 shows part of a system 700 in which two pairs of detectors, a detector Z 702 and a detector X 704 are used to determine the direction of both movements Z and X. In the preferred embodiments of the present invention, the detector Z and detector X each consist of a pair of cross-polarized detectors, such as those illustrated in Figures 19C and 19D and as element 512 in Figure 18 and element 576 in Figures 19A and 19B. The surface has both directed speeds X and Z (with respect to the detection system). The overall velocity is illustrated as the vector V (Vz in the normal direction and Vx in the parallel direction) in Figure 21. The detector Z 702 is preferably located so that it receives the changed Doppler energy from the surface 12 including only frequency changes based on the Z motion (the light source, which is not illustrated, and is assumed to be normally incident on the rack). The detector X 704 is located in such a way that it receives (for example) the first-order diffraction of the grid and the changed Doppler reflections of the surface 12 at an angle f with respect to the normal. The changed Doppler reflections of detector X are based on a combination of the Doppler changes of the X and Z directed motion of the surface with respect to the detectors. Let Ux be the velocity component along the bisector between the zero order and the first order. Then: Ux = Vxsen (f / 2) + Uzcos (f / 2). The Doppler effect creates a frequency change measured in the X and Z detectors, respectively: Fx = 2Uxcos (f / 2) / ?, and Fz = 2Uz / ?. The velocity along the X axes, Vx, can be determined from the measurable quantities Fx and Fz by combining the above relations to: Vx =? Fx / sin (f) -? Fzctg (f / 2) / 2. If the first grid order is used, then the sin (f) =? / ?, where A is the spacing of the grid line. Therefore: V? =? (F? - Fzcos2 (f / 2)). When f is smaller, cos2 (f / 2) ~ 1, simplifying the decoupling of Z: V? =? (F? - Fz).
For the determination of the movement X and Y three detectors are used as illustrated in Figure 22A, which illustrates the detectors in the focal plane of the 700 system. If a more accurate decoupling is required, a separate zero-order detector can be used. By diverting a small portion of the illumination beam at an angle of f / 2, the new zero order of the beam measurements deflected only the movement of the Z axis, but the Doppler frequency is now multiplied by 1 + cos ( f) = 2cos2 (f / 2), for example - it will coincide exactly with the coupling of the movement of the Z axis to the measurements of the X and Y axes, making possible the precise decoupling thereof. In a preferred alternative embodiment of the present invention, it is also possible to decouple the effects of the directed motion X and Z using only reflections of the non-zero order.
This may be desirable since it eliminates detection at frequencies close to zero. Assuming, just for simplicity of exposure, a normal illumination, three detectors i = 1 .. 3 are used, each representing a spacing of the grid of A., and are placed at angles? ¡With respect to the X axis and in the XY plane. Therefore, the detectors measure the number of cycles, N, of a pseudo-sinusoidal signal according to:
N¡ = (1 + cos (f,)), where X and Y are the translations along the X and Y axes, respectively, Z is the component of translation along the
normal to the plane,? is the wavelength of the source and fj is the
i-0 angle of the detector with respect to the direction of illumination in
the plane of reflection, and is related to? ¡as:
? / sin (f¡) = /? If, for example, one detector is on the X axis (?? = 0), the other on
the Y axis (? 2 = p / 2) and the third is at 45 ° with respect to the others
(? 3 = p / 4), then:
FOR, ?
And z N2 = + (1 + cos f2)? 2?
2 X + Y Z N3 = ^ - ± - (1 + cos f3) 2? 3?
The following approximation can be taken: 1 + cos fi = 1 + cos f2 = 1 + cos f3 = kz.
Also, if a simple two-dimensional grid with a square unit element is used (see Figure 22B),
then (assuming they are also small f angles):
Ai =? 2 = A A? 3 = 2
where? 3, remains for the first order at 45 ° from the X axis. In Figure 22B, the element 710 is the first-order detector Y; 712 is the first order detector X and 714 is the first order detector X + Y. Substitution and rearrangement lead to expressions for X, Y and Z:
X =? (N3 - N2) Y =? (N3 N1)
? Z = (N! + N2 - N3) kz
It is evident that the translation in X and Y is measured in two detectors that are not below the measured axis. This eliminates the
Z-axis coupling and at the same time allows a much better resolution in cases where the direction of movement is close to the perpendicular to one of the main axes.
Another example is similar to the previous one, but when? 3 is
duplicate: Ai =? 2 = A
This configuration is equivalent to a detector on the X axis, and a second on the Y axis, and the third midway between them (see Figure 22C), so that the three detectors form a straight line. In Figure 22C, 714 'indicates the combined order detector (X + Y) / 2. This configuration is preferable for manufacturing purposes (especially considering the lightning separator used for direction detection using the static phase change). It can also be easily obtained with a dedicated two-dimensional phase grid. To convert the translation along the axis, in this case: X =? (2N3 - N2)
Y =? (2N3 - N?)
? Z = (Ni + N2 - 2N3) kz
Still another possible configuration is when one detector (720) is on the X axis and the other two (722 and 724) are placed
symmetrically in relation to it, for example y = 0; ? 2 =?; ?3
= -? and Ai =? x; ? 2 =? 3 =? Y (see Figure 22D).
Assuming again that 1 + cos fi = 1 + cos f2 = 1 + cos f3
= K2 X kzZ? X?
1 kzZ N2 = (X cos? - Y sin?) - ± -? V?
kzZ N3 = (X cos? - Y sin?) _i_? «?
The following selection is made conveniently (but not necessarily) so that the X and Y resolutions will be identical:
? v? X sen? + cos?
1 cos? sen? Therefore, defining: k = - rearranging:? X? V
Here again, the Z axis is decoupled, and also the resolution is high even in the movement close to the perpendicular for any of the main axes. In addition, for a convenient extraction of the translation of the
Z axis,? is placed in tan (?) = 2, so that:
N2 + N3 Z = 2N?
Any of the distributions of the detector may be the product of a simple two-dimensional grid (although in general it will not be composed of a group of rectangular unit elements), or using two or three separate grids, preferably illuminated by different portions of the initial beam, each contributing to the local oscillator for only one or two detectors. It should be noted that while Figures 22A, 22B and 22C illustrate a simple detector for each of the diffraction orders, in fact, each consists of a pair of crossed polarized detectors, such as those illustrated in Figures 19C and 19D. , and as element 512 in Figure 18 and element 576 in Figures 19A and 19B. The total power of a source used in the apparatuses of the present invention is generally not high. However, it may be desirable in some preferred embodiments of the present invention to provide a mechanism for eye safety to reduce the chances of unexpected hits on the eyes of any user by the laser. In a preferred embodiment of the present invention, an additional detector is provided which is positioned to receive light reflected from the surface, without receiving the reflected or refracted light from the grid at the same time. This can be easily placed by placing an additional detector between the diffraction rays of zero order and diffraction of first order, and any other orders. Conveniently, this detector can also be used simultaneously for the compensation of the Et2 component, as described above. For example, the additional detector may be placed between the elements 34 and 40 of Figures 3A, 3B or 3C; and in analogous positions in other embodiments described above. The light will be incident on the additional detector and the detector will produce a signal only when an object (other than the grid) is placed to reflect light to it. Therefore, if no surface or a finger or other object blocks the beam (and thus reflects the light back to the original detector), it will not produce a signal.
According to a preferred embodiment of the present invention, the source is turned off whenever the light detected by an additional sensor falls below some threshold level. Periodically, for example, every 100 msec, the source is switched on again for a very short period of time to check if the light is incident on the additional detector. If it is, the source is kept on and the device measures the movement if there is one. If not, or a low incident light is detected, the source is extinguished for an additional period of time. This process is repeated until a light signal above the threshold value is detected in the additional detector. Preferably, the hysteresis is introduced at the threshold to avoid parasitic oscillations. Alternatively or additionally, when movement is not detected for a predetermined period of time, for example, by one or a number of minutes, the motion detector is placed in a "sleep mode". In sleep mode the source is extinguished except for short periods (for example, 50 or 100 milliseconds in every second, or in every half second). If during the period (lit), motion is detected, the motion detector is connected to normal operation. The present invention has been described in conjunction with a number of preferred embodiments thereof, which combine various features and various aspects of the present invention. It should be understood that these features and aspects may be combined in different ways and that various embodiments of the present invention may include one or more aspects thereof. The scope of the present invention is defined by the appended claims and not by the specific embodiments described above. As used in the appended claims, the words "comprises", "comprising", "includes", "including" or their conjugates shall mean "including but not necessarily limited to".
Claims (178)
- R E I V I N D I C A C I O N S Having described the present invention, it is considered as a novelty and, therefore, the content of the following CLAIMS is claimed as property: 1 . A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the illumination of the surface with an incident illumination; detecting a first portion of said incident illumination reflected from the surface in a first direction to form a first detected signal, the time of variation of said first signal being in response to relative movement in the first direction, and having the first direction by at least one component in the direction perpendicular to the surface; detecting a second portion of said incident illumination reflected from the surface in a second direction, different from the first direction, to form a second detected signal, the time variation of said second signal being in response to relative movement in a second direction , different from the first direction, said second direction having a component in a direction parallel to the surface and in a direction perpendicular to the surface; and determining the amount of relative movement parallel to the surface free of motion effects perpendicular to the surface from said first and second detected signals. 2. A method, as described in Claim 1, further characterized in that it comprises: generating a third signal from the first and second signals, said third signal being free of the effects of the movement perpendicular to the surface; and the determination of the movement parallel to the surface coming from the third signal. 3. A method, as described in Claim 1, further characterized in that the determination comprises: determining a first movement in the first direction from the first signal; .. determination of the second movement in the second direction from the second signal; and determination of the movement parallel to the surface correcting the second movement determined by the first determined movement. 4. One method, as described in any of the Claims 1 through 3, further characterized, in that said first direction does not have a component parallel to the surface. 5. One method, as described in any of the Claims 1 to 3, further characterized in that the first direction has a component parallel to the surface. 6. A method, as described in any of the preceding Claims, further characterized in that the relative motion perpendicular to the surface is determined based on a Doppler shift of the reflected illumination. 7. A method, as described in any of the preceding Claims, further characterized in that the determination comprises determining the amount of relative movement parallel to the surface directly from the two signals without determining the amount of relative movement perpendicular to the surface. 8. A method, as described in Claim 7, further characterized in that said first detected signal is determined substantially by relative movement parallel to the surface. 9. A method, as described in Claim 7, further characterized in that the first signal detected is in response to relative movement parallel to the surface. 10. A method, as described in any of the preceding Claims, further characterized in that it includes the determination of the relative movement amount perpendicular to the surface. eleven . A method, as described in any of the preceding Claims, further characterized in that determining the amount of relative motion parallel to the surface includes determining the relative amount of motion along two non-collinear directions. 12. A method, as described in any of the preceding Claims, further characterized in that the illumination is incident perpendicularly on the surface. 13. A method, as described in any of the preceding Claims, further characterized in that the detection comprises coherent detection. 14. A method, as described in Claim 13, further characterized in that it includes: the reflection or diffraction of a portion of the illumination of an object, which is part of the measuring apparatus, to act as a local oscillator. 15. A method, as described in Claim 14, further characterized in that the object is a partially reflective object, through which any illumination passes, either incident or reflected. 16. A method, as described in Claim 15, further characterized in that both incident and reflected illumination pass through the object. 17. A method, as described in any of Claims 14 to 16, further characterized in that the object is adjacent to the surface. 18. A method, as described in any of Claims 14 to 17, further characterized in that the object is a grid. 19. A method, as described in Claim 20, further characterized in that the surface is in the near field of the object. 20. A method, as described in Claim 20, further characterized in that the surface is outside the near field of the grid. twenty-one . A method, as described in Claim 20, further characterized in that the grid essentially produces only a simple order of the transmitted illumination that illuminates the surface. 22. One method, as described in any of the Claims 14 to 21, further characterized in that the illumination is at least partially coherent and, where the object is placed within the coherence length of the illumination coming from the surface. 23. A method, as described in any of Claims 14 to 21, further characterized in that local oscillator illumination and reflected illumination are incidents in at least one detector to produce said signals and, where , the illumination of the local oscillator and the reflected illumination are at least partially coherent in the detector. 24. An apparatus for measuring the relative movement between the apparatus and a surface, which comprises: a source of illumination, which transmits the illumination to illuminate the surface; a first detector which receives the illumination of the source after its reflection from the surface; an object which reflects a portion of the illumination of the illumination source to said first detector, so that the first detector generates a first signal based on the coherent detection of the illumination reflected from the surface with the illumination that is reflected by the object, functioning as a local oscillator; a second detector which receives the illumination of one of the object and the surface without receiving illumination of the other of the surface and the object and generates a second signal in response to it; a signal corrector that adjusts the first signal by the changes in the intensity of the illumination, based on the second signal; and a motion calculator that calculates the relative movement in response to the signal of the signal corrector. 25. The apparatus, as described in Claim 24, further characterized in that the illumination of the second detector is illumination from the source reflected from or diffracted by the object. 26. The apparatus, as described in Claim 25, further characterized in that said apparatus includes: a third detector that receives illumination reflected from the surface without receiving substantial illumination of the object or source and produces a third signal in response to the same, and where the signal corrector corrects the adjusted signal based on the third signal. 27. The apparatus, as described in Claim 24, further characterized in that the illumination of the second detector is the illumination reflected from the surface; 28. The apparatus, as described in any of Claims 24 to 27, further characterized in that the signal corrector corrects the first signal by a constant term based on the second signal. 29. The apparatus, as described in Claim 28, further characterized in that the signal corrector includes a difference amplifier that receives the first signal and subtracts the second signal therefrom to produce a first adjusted signal. 30. The apparatus, as described in Claim 29, further characterized in that the signal corrector includes a normalizer that receives the first adjusted signal and normalizes it with respect to the second signal. 31. The apparatus, as described in any of Claims 24 to 30, further characterized in that the object is partially transmitting and wherein the object is placed between the illumination source and the surface, such that illumination of the surface passes through the object. 32. The apparatus, as described in Claim 31, further characterized in that the illumination has a coherence length and wherein the object and the surface are located within said coherence length. 33. The apparatus, as described in any of the Claims 24 to 32, further characterized in that the object is a grid. 34. The apparatus, as described in Claim 33, further characterized in that the grid essentially produces only a simple command of transmitted illumination that illuminates the surface. 35. The apparatus, as described in Claim 33, further characterized in that the surface is within the near field of the grid. 36. The apparatus, as described in Claim 33, further characterized in that the surface is outside the near field of the grid. 37. The apparatus, as described in any of Claims 24 to 36, further characterized in that the illumination reflected from the surface and the illumination reflected by the object are at least partially coherent in the first detector. 38. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the illumination of the surface with incident illumination, so that the illumination is reflected from portions of the surface; the coherent detection of the illumination reflected from the surface using the illumination derived from said incident illumination that was not reflected by the surface as a local oscillator, to form at least two signals; determining the relative motion magnitude of the surface from at least one of the two signals; the variation of the phase of at least part of the illumination of the local oscillator with respect to at least part of the illumination reflected by the surface; and determining the direction of relative motion parallel to the surface based on a characteristic of the signal caused by said varied relative phase. 39. A method, as described in Claim 38, further characterized in that the illumination of the local oscillator is generated by reflection or diffraction of the incident illumination from an object that is a part of the measuring apparatus. 40. A method, as described in Claim 39, further characterized in that the object is adjacent to the surface. 41 A method, as described in Claims 39 or 40, further characterized in that the illumination has a coherence length and wherein the object and the surface are located within said coherence length. 42. A method, as described in any of the Claims 39 to 41, further characterized in that the object is a grid. 43. A method, as described in Claim 42, further characterized in that the grid essentially produces only a simple command of transmitted illumination that illuminates the surface. 44. A method, as described in Claim 42, further characterized in that the surface is positioned within the near field of the grid. 45. A method, as described in Claim 42, further characterized in that the surface is positioned outside the near field of the grid. 46. A method, as described in any of Claims 38 to 45, further characterized in that the variation of the phase comprises the introduction of a static phase change and wherein the determination of the direction of the relative movement comprises the determination of the direction of relative movement based on a characteristic of the signal caused by said static phase change. 47. A method, as described in any of the Claims 38 to 46, further characterized by including: the division of the illumination that is reflected from the surface in a first illumination having a first phase and a second illumination that It has a second phase. 48. A method, as described in Claim 47, further characterized in that the first illumination and the second illumination have different polarizations. 49. A method, as described in Claim 47 or Claim 48, further characterized in that the division comprises the passage of incident illumination on the surface through a birefringent material. 50. A method, as described in any of the claims 47 to 49, further characterized in that the division comprises the passage of illumination reflected from the surface through a birefringent material. 51 A method, as described in any of Claims 39 to 46, further characterized by including the placement of a birefringent material between the object and the surface. 52. A method, as described in Claim 51, further characterized in that the placement of the birefringent material between the object and the surface is operative to cause the detected illumination to pass through the birefringent material twice. 53. A method, as described in any of Claims 38 to 52, further characterized by including the determination of the magnitude and direction of the translation using two detectors, which produce different detected signals depending on the direction of the translation. 54. A method, as described in Claim 53, further characterized in that the determination of the direction of translation comprises the determination of the direction from the sign of the phase difference between the different detected signals. 55. A method, as described in any of Claims 38 to 54, further characterized in that it includes linear polarization illumination reflected from the surface. 56. A method, as described in any of Claims 38 to 55, further characterized in that the determination of the relative motion magnitude comprises the zero crossing count of the signal. 57. The apparatus for determining the translation of a surface in relation to the apparatus, which comprises: an optical block; a detector, which produces a signal in response to the light hit in the same adhered to the optical block; and and a light source that produces illumination, a portion of which passing through the block is reflected by the surface and strikes the detector after passing through the optical block; and a circuit system that calculates the magnitude of the translation parallel to the surface, in response to the signal. 58. The apparatus as described in Claim 57, further characterized by including an object within or on the surface of the block which reflects or diffracts a part of the illumination to the detector without said part colliding with the surface, said part acting as local oscillator by synchronized detection of the illumination reflected by the detector. 59. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface with incident radiation so that illumination is reflected from a portion of the surface; detecting at least a part of the illumination reflected from the surface to form a first detected signal; detecting at least a second part of the illumination reflected from the surface to form a second detected signal; and determining the relative amount of movement based on a Doppler shift of the reflected radiation, wherein the first and second signals are in quadrature phase and the detection comprises the detection of quadrature. 60. A method as described in Claim 59, further characterized in that it includes: detecting the direction of relative movement in response to said first and second signals. 61 A method as described in Claims 59 or 60 further characterized in that it further includes determining the relative motion in two non-collinear directions parallel to the surface. 62. OR? method as described in any of the Claims 59 through 61 characterized, also because It includes the determination of relative motion in a direction perpendicular to the surface. A method as described in any of Claims 59 to 62, further characterized in that the determination of the relative movement comprises the zero crossing count of at least one of said first and second signals. 64. A method as described in any of Claims 59 to 63, further characterized in that the detection comprises coherent detection. 65. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface with incident illumination so that the illumination is reflected from portions of the surface; the coherent detection of the illumination reflected from the surface using a detector, to form a signal; the use of the illumination derived from said incident illumination that was not reflected by the surface as a local oscillator, for said coherent detection; and determining the magnitude of the relative movement of the surface from the signal; characterized in that the local oscillator is focused on a small area of the detector, so that essentially only a simple spatial frequency of the reflected illumination forms an interference field with said local oscillator in the detector. 66. An apparatus for determining the relative movement of a surface with respect to the apparatus, which comprises: a cover having an opening formed therein; a detector inside the cover that produces a signal used to determine the relative movement; a laser illumination source of a given wavelength, inside the cover, which illuminates the surface through the aperture, so that the illumination is reflected from the surface by means of the aperture to the detector; and a filter that covers the aperture that passes the determined wavelength while blocking light at other wavelengths at which the detector is sensitive. 67. An apparatus for determining the relative movement of a surface with respect to the apparatus, which comprises: a cover having an aperture formed therein; a detector inside the cover that produces a signal used to determine the relative movement; a laser illumination source of a given wavelength inside the cover, which illuminates the surface through the aperture, so that the illumination is reflected from the surface by means of the opening of the detector; a second detector inside the cover that receives the illumination reflected from the surface; and a circuit system that turns off the light source when the illumination received by the second detector falls below a threshold.68. An apparatus as described in Claim 67, further characterized in that the circuit system is operable to periodically turn on the source and to turn it off if the illumination received by the second detector is below the threshold. 69. The apparatus as described in Claims 67 or 68, further characterized in that the aperture is covered by a filter that passes the determined wavelength while blocking the light at other wavelengths at which the first and second wavelengths are sensitive. detectors 70. The apparatus as described in any of Claims 66 to 69, further characterized in that a part of the illumination to the detector illuminates the detector, without said first part colliding with the surface, said part acting as a local oscillator for the coherent detection of the illumination reflected by the detector. 71 An apparatus as described in any of the Claims 66 through 70, characterized in that the reflected illumination is subjected to a Doppler shift, by said translation, with respect to the illumination produced by the source and wherein said Doppler shift is used in the determination of the movement. 72. The apparatus for measuring the relative movement between the apparatus and a surface which comprises: a source of illumination which is used to illuminate the surface; a detector which receives the illumination of the source, reflected from the surface and which receives a portion of the illumination without said portion being reflected by the surface, so that the detector generates a signal based on the coherent detection of the illumination reflected from the surface with the portion of the illumination in the form of the local oscillator, wherein said signal has a frequency related to a relative movement rate; and a motion calculator that calculates the relative amount of movement in response to a zero crossing of the signal. 73. The apparatus as described in Claim 72, further characterized in that the detector includes a high pass filter that filters the output of the detector to form said signal. 74. The apparatus as described in Claim 73, further characterized in that the high pass filter has a slope of less than about 20 dB / eighths. 75. The apparatus as described in Claims 73 to 74, further characterized in that the high pass filter has a breaking point at a frequency corresponding to a movement rate less than about 0.5mm / sec. 76. The apparatus as described in any of Claims 72 to 75, further characterized in that it includes: a second detector that detects at least a second part of the illumination reflected from the surface to form a second detected signal using the coherent detection, wherein the motion detector determines the relative amount of movement based on a Doppler shift of the reflected radiation, and wherein the detected signal and the second signal are in quadrature phase, and the detection comprises the detection of the quadrature . 77. The apparatus for determining the relative movement of a surface with respect to the apparatus, further characterized in that it comprises: a cover having an opening formed therein; uh detector inside the cover that produces a signal used in the determination of the movement in which the determination of the movement is determined; a laser illumination source for a given wavelength inside the cover, which illuminates the surface through the aperture so that the illumination is reflected from the surface and by means of the aperture to the detector; and the circuit system that turns off the light source when the illumination received by the detector from the surface is below a threshold. 78. The apparatus as described in Claim 77, further characterized in that the circuit system is operable to periodically light the source and to turn it off if the illumination received by the detector from the surface. 79. The apparatus for determining the relative movement of a surface which comprises: a partially transmitting object located adjacent to the surface; a detector that detects the incident light in it and generates a detected signal; a source of illumination which illuminates the object with incident illumination so that the illumination is reflected or diffracted towards the detector from the object and so that part of the incident illumination is reflected from the surface towards the detector so that the detector detects in a coherent way the illumination reflected from the surface using the reflected or diffracted illumination towards the detector from the object; and a circuit system which determines the relative movement of the surface parallel to the surface with respect to the apparatus from the detected signal. 80. The method for determining the relative movement of a surface with respect to a measuring apparatus which comprises: placing an object that partially transmits as part of the measuring apparatus, adjacent to the surface; the illumination of the surface with incident illumination so that the illumination is reflected from portions of the surface, wherein at least part of at least one of the incident and reflected illumination passes through the object; detecting the illumination reflected from the surface, to generate a detected signal, wherein the object and the surface are located within a distance that is less than the coherence length of the detected illumination; and determining the relative movement of the surface parallel to the surface, from the detected signal. 81. A method as described in Claim 80, further characterized in that the transmission of the object is spatially variable. 82. A method as described in claims 80 or 81, further characterized in that the object is partially reflective and where part of the incident illumination of the illumination reflected or diffracted by the object, as a reference illumination and where the detection of the lighting is coherent, using said reference illumination. 83. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the positioning of a partially reflecting object, which is part of the measuring apparatus, adjacent to the surface; the illumination of the object with the incident illumination so that part of the incident illumination is reflected or diffracted by the object, as a preferred illumination and part is reflected from the surface; the coherent detection of the illumination reflected from the surface using the reference illumination to generate a detected signal; and determining the relative movement of the surface parallel to the surface, from the detected signal. 84. A method as described in Claim 83, further characterized in that the object is a partially transmitting object and wherein at least part of at least one of the incident and reflected illumination passes through the object. 85. A method as described in Claims 83 or 84, further characterized in that the reflection of the object is spatially variable. 86. A method as described in Claims 81 or 85, further characterized in that the spatial variation comprises the periodic spatial variation. 87. A method as described in any of Claims 80 to 86, further characterized in that the placement of an object adjacent to the surface comprises: the placement of a grid adjacent to the surface. 88. A method as described in claim 87, further characterized in that the placement of a grid adjacent to the surface comprises: the placement of a grid sufficiently close to the surface, so that the surface is in the near field of the rack. 89. A method as described in claim 87, further characterized in that the placement of a grid adjacent to the surface comprises: the placement of a grid sufficiently far from the surface, so that the surface is outside the near field of the rack. 90. A method as described in any of the Claims 80 to 89, further characterized in that the detected illumination is at least partially coherent. 91 A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the placement of a grid which is part of the measuring apparatus, adjacent to the surface; the illumination of the grid with an incident illumination so that at least part of the illumination is incident on and reflected from the surface, wherein at least one of the incident and reflected illumination passes through the grid; the generation of a signal in response to reflected illumination; and determining the relative motion of the surface parallel to the surface, from the detected signal, where the surface is in the near field of the grid. 92. A method as described in Claim 91, further characterized in that the generation of the signal, comprises the detection of the illumination reflected from the surface, using a reference illumination. 93. A method as described in any of the claims from 80 to 92, further characterized in that the illumination reflected from the surface is frequently changed from the illumination reflected from or diffracted by the object and where the determination of the movement comprises the determination of the movement based on the change of frequency. 94. A method as described in any of Claims 80 to 93, further characterized in that the object has transmission characteristics that are spatially asymmetric. 95. A method as described in claim 94, further characterized in that it includes: determination of the relative motion direction based on a characteristic of the signal caused by said asymmetry. 96. A method for determining the relative movement of a surface with respect to a measuring apparatus which comprises: the positioning of a partially transmitting object, which is part of the measuring apparatus, adjacent to the surface; the illumination of the surface with incident lighting, which does not constitute an interference pattern so that the illumination is reflected from portions of the surface, where at least part of at least one of the incident or reflected illumination passes through of the object the detection of the illumination reflected from the surface and generation of a detected signal; and determining the relative movement of the surface parallel to the surface, from the detected signal. 97. A method as described in any of Claims 80 to 96, further characterized in that it comprises: the phase variation between the illumination reflected from or diffracted by the object and at least a portion of the illumination reflected from the surface. 98. A method as described in Claim 97, further characterized in that the address is determined based on said varied phase. 99. A method as described in any of the claims from 80 to 98, further characterized by including the determination of the movement in a direction perpendicular to the surface. 100. A method for determining the relative movement of a surface with respect to a measuring apparatus which comprises: the illumination of the surface with the incident illumination so that the illumination is reflected from portions of the surface; the placement of a partially reflecting object, which is part of the measuring apparatus, adjacent to the surface, where part of the incident illumination is reflected or diffracted by the object, as a reference illumination; the coherent detection of the illumination reflected from the surface using the illumination reflected from or diffracted by the object as a local oscillator to form a signal; the determination of the relative movement of the surface from the signal; the variation of the phase of at least a part of the illumination reflected from, or diffracted by, the object with respect to at least a part of the illumination reflected from the surface; and the determination of the relative motion parallel to the surface based on a characteristic of the signal caused by said varied relative phase. A method as described in Claim 100, further characterized by the placement of a reflector adjacent to the surface which comprises: the placement of a grid adjacent to the surface. A method as described in any of Claims 97 to 101, further characterized in that the variation of the phase comprises the periodic variation of the phase. 103. A method as described in Claim 102, further characterized in that determining the direction of relative motion comprises determining the direction of relative motion based on a characteristic of the signal caused by the relative phase of periodic variation. 104. A method as described in any of Claims 97 to 103, further characterized in that the variation of the phase comprises: causing an object to move in a substantially periodic manner in the direction of the movement being measured. 105. A method as described in any of Claims 97 to 104, further characterized in that the variation of the phase comprises: causing the object to move periodically substantially parallel to the direction of the movement being measured. 106. A method as described in any of Claims 97 to 105, further characterized in that the variation of the phase comprises: providing a transparent material between the object and the surface; and electrify the material so that its optical length in the direction of illumination varies. 107. A method as described in Claim 106, further characterized in that the transparent material is a piezoelectric material. 108. A method as described in any of Claims 96 to 107, further characterized by including the variation of both the magnitude and the direction of translation using a single detector. 109. A method as described in any of the claims from 97 to 101, further characterized in that the variation of the phase comprises, the introduction of a static phase change and wherein the determination of the direction of relative movement comprises the determination of the direction of relative movement based on a characteristic of the signal caused by said phase change. 10. A method as described in any of the claims from 97 to 109, further characterized in that it includes: the division of at least part of the illumination that is reflected from the surface, within at least one first illumination having a first phase and a second illumination having a second phase. 1 1 1 A method as described in Claim 1 10, further characterized in that said first and second illuminations have different polarizations. 112. A method as described in Claim 108, further characterized in that the division comprises passing the incident illumination over the surface through a birefringent material. 113. A method as described in Claims 1 1 1 or 12, further characterized in that it includes passing the illumination reflected from the surface through a birefringent material. 14. A method as described in Claims 12 or 13, further characterized in that it includes the placement of the birefringent material between the object and the surface. 15. A method as described in claims 96 to 107 or 109 to 14, further characterized in that it includes the determination of the magnitude and direction of the translation using two detectors which produce two signals detected different depending on the direction of the translation. r 16. A method as described in claim 15, further characterized in that it includes the determination of the direction of translation from the sign of a phase difference between the different detected signals. 17. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the placement of a perforated reflector, which is part of the measuring apparatus adjacent to the surface; the illumination of the surface with incident illumination so that the illumination is reflected from portions of the surface and so that the illumination is reflected from or diffracted by the perforated reflector; the coherent detection of the illumination reflected from the surface using the illumination reflected from or diffracted by the perforated reflector as a local oscillator to form a signal; the determination of the relative movement of the surface perpendicular to and parallel to the perforated reflector from the signal. 18. A method as described in claim 18, further characterized in that: the coherent detection comprises: the detection of amplitude or phase variations of the reflected illumination; and detecting a frequency change of the reflected illumination; and determining the relative movement comprises: measuring the relative movement of the surface in a direction parallel to the perforated reflector in response to at least one of the amplitude or phase variations detected; and measuring the relative movement of the surface in a direction perpendicular to the surface of the perforated reflector in response to the detected frequency change. 119. A method as described in Claim 1 18, further characterized in that it comprises: the periodic movement of the surface of the perforated reflector in a direction perpendicular to its surface to add a periodic phase change to the illumination reflected therefrom; and the use of said phase change to measure the movement of the surface. 120. A method for determining the relative movement of a surface with respect to a measuring apparatus which comprises: the illumination from the surface, from a source, with incident illumination, so that the illumination is reflected from portions of the surface towards a detector; the spatial filtering of the reflected illumination so that the phase of the optical illumination detected from a given disperser on the surface is substantially constant or is linearly related to the translation of the surface; the generation of a signal by the detector in response to the incident illumination in the detector; and the determination of the relative movement of the surface from the signal. 121. A method as described in Claim 120, further characterized in that the illumination comprises the illumination of the surface with a spatially variable illumination. 122, A method as described in Claim 120 or 121, further characterized in that the illumination of the surface comprises the illumination of the surface through a perforated reflector positioned adjacent to the surface which reflects or diffracts the illumination to the detector . 123. A method as described in Claim 122, further characterized in that the generation of a signal comprises the coherent detection of the illumination reflected from the surface using the reflected or diffracted illumination from the perforated reflector. 124. A method as described in any of Claims 120 through 123, further characterized in that the determination of the relative movement comprises the use of a Doppler shift of the reflected illumination. 125. A method as described in any of the Claims 120 to 124, further characterized in that: the illumination of the surface is substantially collimated; the spatial filter filters the reflected illumination so that substantially only a simple spatial frequency of the reflected illumination is detected by the detector. 126. A method as described in any of the Claims 120 to 125, further characterized in that: the illumination of the surface is substantially collimated; and the spatial filtering filters the reflected illumination so that only the illumination reflected from the surface substantially in a single direction is detected by the detector. 127. A method as described in any of Claims 120 to 126, further characterized in that the special filtration comprises: focusing the reflected illumination with a lens having a focal point; and the placement of a minute aperture in the focal point of the lens. 128. A method as described in any of Claims 120 to 126, further characterized in that the spatial filtering comprises: focusing the illumination reflected with a lens having a focal point; and the placement of an optical fiber in a simple way at the focal point of the lens to transfer the illumination to the detector. 129. A method as described in any of Claims 120 to 126, further characterized in that the spatial filtering comprises: focusing the illumination reflected with a lens; and the placement of a minute aperture in an image of the source. 130. A method as described in any of Claims 120 to 126, further characterized in that the spatial filtering comprises: focusing the illumination reflected with a lens; and placing an optical fiber in a simple manner in a source image to transfer the illumination to the detector. 131 A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: the positioning of an object having at least an almost continuous transmission function adjacent to the surface; the illumination of the surface with incident lighting so that the illumination is reflected from portions of the surface towards a detector; detecting the reflected light from the surface using the detector to generate a signal; and the determination of the relative movement of the surface from the signal. 132. A method as described in Claim 131, further characterized in that the object has an asymmetric transmission function; and wherein the determination of the relative movement comprises the determination of the direction of movement based on the detected signal. 133. A method as described in claim 131 or 132, further characterized in that: the illumination is reflected from or diffracted by the object to the detector; and said detection is a coherent detection that uses the illumination reflected from or diffracted by the object as a local oscillator to form a signal. 134. A method of determining the relative movement of a surface with respect to a measuring apparatus which comprises: illuminating the surface with illumination through the perforated reflector so that the illumination is reflected from the surface to illuminate a detector with illumination the which is not an image of a point on or a portion of the surface; the simultaneous illumination of the detector with the reference illumination derived from said incident illumination; the coherent detection of the reflected illumination of the detector using said reference illumination so that the detector generates a signal; the determination of the relative movement of the surface parallel to the surface, based on the variations of the signal caused by the relative movement. 135. A method as described in Claim 134, further characterized in that the incident illumination is at a given wavelength and wherein the reference illumination is at the same wavelength so that the coherent detection is a homodyne detection. 136. A method as described in Claims 134 or 135, further characterized in that it comprises: the spatial variation of the illumination of the surface. 137. A method as described in Claim 136, further characterized in that the spatial variation of the illumination of the surface comprises: the illumination of the surface through a transmission grid having a spatially variable periodic transmission. 138. A method as described in claim 133, further characterized in that the spatial variation of the illumination of the surface comprises: the illumination of the surface through a grid which specularly reflects a portion of the incident illumination thereon towards the detector to form said reference illumination .. 139. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface as illumination so that illumination is reflected from portions of the surface; the placement of a perforated reflector adjacent to the surface; the coherent detection of the illumination reflected from the surface using the illumination reflected from or diffracted by the perforated reflector as a local oscillator; and determining the relative movement of the surface, in a direction parallel to the surface, from a characteristic of the signal. 140. A method as described in Claim 139, further characterized in that the relative motion is detected using a Doppler shift of the illumination reflected from the surface. 141. A method as described in Claims 139 or 140, further characterized in that the perforated reflector is a grid and wherein the illumination diffracted by the grid is used in the determination of the movement 142. A method as described in any of the claims from 80 to 141, further characterized in that the illumination is perpendicularly incident on the surface. 143. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface with illumination so that the illumination is reflected from portions of the surface; the placement of a partially reflecting object adjacent to the surface; the coherent detection of the illumination reflected from the surface, using the illumination reflected from or diffracted by the partially reflecting object as a local oscillator; and determining the relative movement of the surface, in a direction parallel to the surface, from a characteristic of the signal based on reflection reflected from the surface. 144. A method for determining the relative movement of a surface with respect to a measuring apparatus, which comprises: illuminating the surface from a source, with incident illumination so that illumination is reflected from portions of the surface toward a detector; the spatial filtering of the reflected illumination so that the phase of the optical illumination detected from a given disperser on the surface is substantially constant or is linearly related to the translation of the surface. the generation of a signal by the detector in response to the incident illumination in the detector; and the determination of the relative movement of the surface from the signal. 145. A method as described in Claim 144, further characterized in that determining the relative movement of the surface comprises determining the relative movement of the surface in a direction parallel to the surface. 146. A method as described in Claims 144 or 145, further characterized in that the illumination comprises the illumination of the surface with a spatially variable illumination. 147. A method as described in any of the Claims 144 to 146, further characterized in that the illumination of the surface comprises the illumination of the surface through a partially reflecting object placed adjacent to the surface which reflects or diffracts the lighting to the detector. 148. A method as described in Claim 146, further characterized in that the generation of a signal comprises the coherent detection of the illumination reflected from the surface using the reflected or diffracted illumination from the partially reflecting object. A method as described in any of the Claims 144 to 148, further characterized in that the determination of relative movement comprises the use of a Doppler shift of the reflected illumination. 150. A method as described in any of the Claims 144 to 149, further characterized in that: the illumination of the surface is substantially collimated; and the spatial filtering filters the reflected illumination so that substantially only a simple spatial frequency of the reflected illumination is detected by the detector. 151 A method as described in any of the Claims 144 to 150, further characterized in that: the illumination of the surface is substantially collimated; and the spatial filtering filters the reflected illumination so that only the illumination reflected from the surface substantially in a single direction is detected by the detector. 152. A method as described in any of Claims 1 to 23, 59 to 65, 80 to 94, 1 17 to 131 or 134 to 151, further characterized because it includes the determination of the direction of the movement. 153. a method for determining the direction of relative movement of a surface with respect to the measuring apparatus, which comprises: illuminating the surface with incident radiation so that radiation is reflected from portions of the surface towards a detector; the placement of an object, which has an asymmetric transmission function adjacent to the detector; detecting the reflected radiation from the surface using the detector to generate a signal; and the determination of the direction of the movement in relation to the surface from the signal. 154. A method as described in any of Claims 1 to 23, 59 to 65, or 80 to 153, further characterized in that the determination of the movement comprises the variations of determination in the amplitude of the signal with the position. 155. A method as described in Claim 154, further characterized in that the movement is determined from the zero crossings of the detected signal. 156. A method as described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 155, further characterized in that the surface is a diffusely reflecting surface optically 157. A method as described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 156, further characterized in that the surface does not have markings indicating the position. 158. A method as described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 157, further characterized in that the illumination comprises visible illumination. 159. A method as described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 157, further characterized in that the illumination comprises infrared illumination. 160. A method as described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 159, further characterized by including the detection of movement in relation to with the surface in two directions parallel to the surface. 161 An optical mouse which comprises: a cover having an opening facing the surface; and an optical motion detector which is oriented toward the surface through the aperture, wherein the optical motion detector uses the method as described in any one of Claims 1 to 23, 38 to 56, from 59 to 65 or 80 to 160, to determine the translation of the roof with respect to the surface. 162. A contact point for use as a control apparatus, which comprises: a cover having an opening; and an optical detector which determines the movement of a finger which is translated through the opening where the optical detector uses the method as described in any of the Claims 1 through 23, 38 through 56, 59 through 65, or 80 through 160, to determine the translation. 163. A pointing apparatus which comprises: a first contact point as described in Claim 161, and a circuit system which moves the flag in response to it; and a second contact point as described in Claim 161, and including a circuit system which causes the spiral response thereof. 164. A contact point / mouse combination to be used as a signal for a computer, which comprises: a cover that has an opening; an optical detector which determines the movement of an object which is moved across the width of the aperture; and means for determining whether the opening is oriented up or down. 165. A contact point / mouse combination as described in Claim 164, further characterized in that the optical detector uses the method as described in any of Claims 1 to 23, 38 to 56 , from 59 to 65 or from 80 to 160, to determine the translation. 166. An explorer (scanner) to read a document by means of the movement of the scanner on the document, which comprises: an optical reading head which detects the patterns on the surface of the document; and an optical detector which determines the movement of the scanner as it moves across the surface of the document, wherein the optical detector uses the method as described in any of Claims 1 to 23, 38 to 56, from 59 to 65 or from 80 to 160, to determine the translation. 167. An explorer (scanner) as described in Claim 166, further characterized in that the pattern comprises printed patterns. 168. An explorer (scanner) as described in Claims 166 or 167, further characterized in that the patterns "are handwritten patterns. 169. An explorer as described in Claim 168, further characterized in that the patterns are a signature. 170. An encoder which comprises: an optically diffuse reflecting surface that has no different marks to the reference marks; and an optical detector having a relative movement with respect to the surface, wherein the optical detector measures the relative movement with respect to the surface in relation to the reference marks, and wherein the optical detector uses the method as set forth in FIG. described in any of Claims 1 to 23, 38 to 56, 59 to 65 or 80 to 160. 171. An encoder as described in Claim 170, further characterized in that the surface is the surface of a disk which rotates about an axis, and wherein the detector measures the rotation of the disk. 172. A virtual pen, which comprises: an encoder as described in Claims 170 or 171; and a circuit system which translates said relative movement measured in writing or graphic data. 173. An apparatus for moving a sheet of paper, which comprises: means for moving the paper; and an optical detector which measures the movement of the paper without using some paper marks, wherein the optical detector uses the method as described in any of Claims 1 to 23, 38 to 56, from 59 to 65 or from 80 to 160. 174. A document scanner, which comprises: an apparatus as described in Claim 173; a reading head which reads the information from the paper; and a memory which stores the information in the locations of the memory in response to the measurement of the movement of the paper. 175. A printing machine which comprises: an apparatus as described in Claim 173; a memory which contains information that is going to be printed on the sheet of paper; and a printer head which prints the information in response to the measurement of the movement of the paper. 176. A fax machine comprising an explorer as described in Claim 174. 177. A fax machine which comprises a printer as described in Claim 175. 178. A fax machine as described in the Claim 174, further characterized in that it additionally comprises an explorer as described in Claim 175. SUMMARY A method for determining the relative movement of a surface in relation to a measuring apparatus which comprises the steps of: Illumination of the surface with illumination, detection of the illumination reflected from the surface to form at least one detected signal; and determining the amount of relative movement parallel to the surface from said at least one detected signal; characterized in that said determination includes the correction of the effects of the relative movement perpendicular to the surface.
Applications Claiming Priority (5)
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| PCT/IL1998/000113 WO1999046602A1 (en) | 1998-03-09 | 1998-03-09 | Optical translation measurement |
| IL12430098A IL124300A0 (en) | 1998-03-09 | 1998-05-03 | Optical translation measurement |
| IL12543198A IL125431A0 (en) | 1998-03-09 | 1998-07-20 | Optical translation measurement |
| IL12665698A IL126656A0 (en) | 1998-03-09 | 1998-10-19 | Optical translation measurement |
| PCT/IL1999/000137 WO1999046603A1 (en) | 1998-03-09 | 1999-03-09 | Optical translation measurement |
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-
1999
- 1999-03-09 NZ NZ506914A patent/NZ506914A/en unknown
- 1999-03-09 AU AU27439/99A patent/AU750415B2/en not_active Ceased
- 1999-03-09 CN CNB998002534A patent/CN1144063C/en not_active Expired - Lifetime
- 1999-03-09 CA CA002322874A patent/CA2322874A1/en not_active Abandoned
- 1999-03-09 WO PCT/IL1999/000137 patent/WO1999046603A1/en not_active Application Discontinuation
- 1999-03-09 EP EP99907827A patent/EP1062519A2/en not_active Withdrawn
- 1999-03-09 CN CNA2003101027889A patent/CN1548963A/en active Pending
- 1999-03-09 JP JP54555899A patent/JP3321468B2/en not_active Expired - Fee Related
- 1999-03-09 MX MXPA00009038A patent/MXPA00009038A/en unknown
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| WO1999046603B1 (en) | 1999-12-02 |
| AU2743999A (en) | 1999-09-27 |
| JP2000508430A (en) | 2000-07-04 |
| CN1548963A (en) | 2004-11-24 |
| WO1999046603A1 (en) | 1999-09-16 |
| JP3321468B2 (en) | 2002-09-03 |
| CN1144063C (en) | 2004-03-31 |
| EP1062519A2 (en) | 2000-12-27 |
| NZ506914A (en) | 2002-12-20 |
| CA2322874A1 (en) | 1999-09-16 |
| CN1256755A (en) | 2000-06-14 |
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