JP2019163932A - Optical measurement device - Google Patents

Abstract

To provide an optical measurement device that calculates optical distance information and intensity information by accurately separating the intensity and the optical distance based on a signal acquired from a light receiving element.SOLUTION: A laser light source 21, a collimator lens 22, a pupil transmission lens system 25, a two-dimensional scanning device 26, and a beam splitter 27 are arranged side by side. An objective lens 31 faces a measurement object G1. A light receiving element group 29 on the left side of the beam splitter 27 is composed of light receiving elements 29A and 29B. Modulation is performed by the two-dimensional scanning device 26 scanning the irradiation light from the laser light source 21 and sending it to the measuring object G1. A signal comparator 33 obtains intensity information and phase information based on signals from the two light receiving elements 29A and 29B received from the measurement object G1 and a signal serving as a reference for scanning by the two-dimensional scanning device 26.SELECTED DRAWING: Figure 1

Description

  In the present invention, intensity information such as transmittance, reflectivity, absorbance, etc. and optical information are measured for measurement of the profile of the surface condition of the measurement object by laser light irradiation, and measurement and observation of the surface condition and internal condition of cells and the like. The present invention relates to an optical measurement device that simultaneously acquires distance information and accurately separates both, and is suitable for a device that improves the performance of an optical instrument such as a microscope.

  In a conventional optical microscope, it is difficult to measure three-dimensionally such as an optical distance, and phase information and intensity information cannot be accurately separated. For example, a phase contrast microscope uses a phase plate to convert phase information into intensity information for observation in order to clearly observe biological cells with low contrast. Therefore, although phase information can be visualized, intensity information has also been observed. Thus, the conventional phase contrast microscope is not a microscope that purely separates and observes only phase information or intensity information. The same applies to the differential interference microscope that visualizes the phase information. In particular, in order to enable three-dimensional measurement, it is necessary to clearly separate optical distance information and intensity information that are phase information.

On the other hand, confocal microscopes, digital hologram microscopes, and the like are known as conventional means for detecting optical path differences.
The former confocal microscope irradiates the measurement object with spot light, and the objective lens or the object lens or the light beam received by the light receiving element disposed at the confocal position via the pinhole is maximized with respect to the spot light. By moving the measurement object, the height information and the path difference information of the measurement object are acquired.

  Further, the latter digital hologram microscope irradiates a measurement object with a substantially parallel laser beam, collects the light diffracted by the measurement object with an objective lens, and provides a reference plane wave and an area such as a CCD. A hologram is created by interference on a sensor. Then, by analyzing the interference fringes by calculation, the wavefront from the original measurement object is restored, and the path difference information is acquired.

  However, in the former confocal microscope, basically, if there is a phase distribution in the spot light, the beam is deformed and becomes erroneous information. In particular, if the object to be measured has a wavefront that changes in phase, such as a change in refractive index of a cell or the like, the reliability of the value must be poor. In addition, since it is necessary to move the objective lens and the measurement object so that the received light quantity becomes maximum, the real-time property is lacking. Furthermore, when the measurement object is such that intensity unevenness occurs due to changes in absorptance or reflectance, the amount of light received naturally changes at the point where the intensity changes, so the amount of light passing through the pinhole is It cannot be determined whether the intensity is increased at the focal point or due to unevenness in intensity, and an incorrect optical distance is calculated.

  In the latter digital hologram microscope, the light diffracted by the objective lens is collected, interfered with a reference plane wave, the bright and dark pattern is taken in by a CCD or the like, and the wavefront is reproduced by a computer as information. However, since the reference plane wave is a plane wave that has passed through several optical elements, even if it is a plane wave, about 1/10 of the wavelength is uneven in the plane. Even if the uneven state of the wavefront is stored in a calibration plane or the like, it is effectively fluctuated due to temperature fluctuations, air density fluctuations, or the like. For this reason, it is difficult to say that the interference pattern between the plane wave and the object wave passing through different paths is reproducing the object wave in a strict sense.

  On the other hand, a method of preparing a Fourier transform surface in a part of the imaging optical system, disposing a phase type spatial modulator on this surface, and applying phase modulation to the 0th-order diffracted light is disclosed in Patent Document 1 and Non-Patent Document 1 below. 2. In this method, a total of four types of images in which a phase difference of 90 degrees is generated between the 0th-order diffracted light and the 1st-order diffracted light are picked up by a CCD camera arranged on the imaging surface. And it is set as the method of measuring an optical distance from the mutual calculation of these four types of images.

  However, at this time, it is effectively impossible to cause a phase difference only in the 0th-order diffracted light. This is because the 0th-order diffracted light is transmitted without being modulated from the sample, but there is a low-order 1st-order diffracted light that overlaps the 0th-order diffracted light region. This is because they cannot be distinguished. Furthermore, it is necessary to switch the modulation of the spatial light modulator when acquiring an image with four different phases, and the image acquired by the CCD camera is time-shifted information. Therefore, it cannot be said that the change of the process which changes relatively rapidly is correctly reflected.

  On the other hand, in order to reduce this influence as much as possible, it is conceivable to apply this method in a very narrow region near the periphery of the spread of the 0th-order diffracted light. In this way, there is a possibility that the frequency dependence of the spatial frequency and the influence of the first order diffracted light included in the zeroth order diffracted light can be reduced. However, since only a very narrow range of light can be acquired effectively, the amount of light is extremely reduced, making it difficult to obtain information with a good SN ratio.

  In response to these circumstances, with the recent development of the micro / nanotechnology field, attention has been focused on a technique for measuring three-dimensional information of fine industrial products and precision parts at high speed. In addition, in biology, medicine, and agriculture, there is an increasing demand for real-time acquisition of three-dimensional profile information of a biological sample having a thickness such as a cell.

  However, basically, all objects have different height information and refractive index distribution, and further have different absorptance, reflectance, etc., and therefore have different intensity information and optical distance information. In the method of analyzing interference fringes including holograms, phase information is converted into interference fringe intensity information and detected by a CCD or the like, so it is inherently difficult to easily separate the original intensity information from the phase information. It is.

Special table 2007-524075 gazette Japanese Patent Laying-Open No. 2015-4643 JP 2013-238450 A JP 2017-116925 A JP 2017-133867 A

Opt. Lett. 29 (21), 2503-2505 (2004) Opt. Exp. 19 (2), 1016-1026 (2011)

  In the above Japanese Patent Application Publication No. 2007-524075 of Patent Document 1, a spatial modulator is used to cause substantially four phase differences with respect to the 0th-order diffracted light. However, it has been difficult to maintain a stable phase difference due to in-plane variation of the spatial modulator, temperature change, and the like. In addition, when a liquid crystal spatial modulator is used, adjustment is difficult because the polarization is rotated in addition to the phase unless the direction of the linearly polarized light and the direction of the liquid crystal molecules are properly matched. Furthermore, since four phase differences are generated by the spatial modulator, a time lag occurs. For this reason, since the four phase information is acquired at different times with respect to a phenomenon with a fast temporal fluctuation, accurate information cannot be acquired.

  As described above, in a conventional microscope, it is impossible to strictly separate general measurement objects whose intensity and optical distance change at the same time. Therefore, correct intensity information and optical distance information are calculated. I couldn't.

  The present invention has been made in view of the above background, and by accurately separating the intensity and the optical distance based on the signal acquired from the light receiving element, the optical distance information and the transmittance, the anti-tilt rate, the absorption rate, etc. It is an object of the present invention to provide an optical measurement device that calculates intensity information of the light.

An optical measurement device according to claim 1 is a light source that emits coherent irradiation light;
A scanning element that scans irradiation light from a light source and sends it to a measurement object;
At least two light receiving elements that are respectively positioned on both sides with a direction perpendicular to the optical axis direction of the irradiation light as a boundary line, and that respectively receive the irradiation light modulated by the measurement object in accordance with scanning and photoelectrically convert the irradiation light; ,
A non-modulated signal, which is a direct current component, and a modulated signal, which is an alternating current component, are extracted from each signal photoelectrically converted by the light receiving element, and intensity information and phase information of the object to be measured are obtained using the non-modulated signal and the modulated signal. And obtaining a measurement value for the measurement object based on the intensity information and the phase information,
including.

The operation of the optical measuring device according to claim 1 will be described below.
In the present invention, coherent irradiation light is irradiated from a light source, and a scanning element scans the irradiation light and sends it to a measurement object as a scanning beam. In addition, two light receiving elements, one on each side of the boundary with the direction perpendicular to the optical axis direction of the irradiated light, receive the irradiated light modulated by the measurement object as a result of scanning, and photoelectrically Convert.

  Then, a non-modulated signal, which is a direct current component of a signal photoelectrically converted by each of these two light receiving elements, and a modulated signal, which is an alternating current component, are extracted by the measuring unit, and the measuring unit uses the extracted signals to measure Get strength and phase information of objects. Furthermore, using the fact that the in-phase signal of the extracted signal is intensity information and the reverse-phase signal is phase information that is optical distance information, the transmittance, reflectance of the measurement object based on the intensity information, A measurement value such as an absorptance is obtained, and a measurement value of optical distance information of the measurement object is obtained based on the phase information.

  In other words, according to the present invention, a scanning element is scanned to form a scanning beam without using a special modulation element such as a spatial modulator to change the phase of the irradiation light from the light source and receiving it with a CCD or the like. The irradiation light passes through the measurement object by irradiating the measurement object and reflecting or transmitting the irradiation light. A signal conversion corresponding to an electrical phase change is performed on the non-modulated signal and the modulated signal generated in association therewith. Accordingly, the optical measurement device according to the present invention can completely separate the intensity information and the optical distance information of the measurement object without using a special device or element.

  As a result of the above, in a microscope or the like to which the present invention is applied, intensity information and optical distance information can be acquired simultaneously from the irradiation position of the scanning beam in the reflection optical system and the transmission optical system. Intensity changes such as changes in the state of cells and micromachines and three-dimensional measurement can be performed in real time. In addition, since it is not a plurality of data acquired by a plurality of CCDs or the like but information from the same observation point, it is a process unrelated to alignment by pixel shift, and different information can be reliably acquired from the same location. .

  When intensity information and height information are mixed, a laser scanning confocal microscope, which is a kind of the above-mentioned confocal microscope that calculates the height with the maximum amount of light passing through the pinhole, gives an error signal. The optical distance information, which is height information, can be calculated with a single scan with certainty in the present apparatus, and thus has very large features.

  Furthermore, when the present invention is applied to a transmission type microscope, as it becomes a simple device, cells and micro-organisms etc. remain alive and are not fluorescently colored, and can be visualized with high resolution and simple and high speed. Observe and measure. In addition, since optical distance information is obtained from phase information and transmittance and absorptance are obtained from intensity information, it has a great feature that some physical quantities of living organisms can be measured alive.

  Next, according to claim 2, a signal photoelectrically converted by each of the two light receiving elements is used as a first signal, and a second signal obtained by performing Hilbert transform on a modulation signal of an AC component and the second signal are further provided. By using the Hilbert-transformed third signal and applying the converted signals to the sum signal and difference signal of the output from one of the two light receiving elements and the output from the other light receiving element, the intensity information In addition, optical distance information can be easily obtained.

Further, as defined in claim 3, the boundary line along a direction perpendicular to the optical axis direction of the irradiation light and a boundary line intersecting the boundary line on the optical axis of the irradiation light are defined. The light receiving elements may be arranged in any region. In this way, the light receiving elements are arranged in the areas divided into a total of four sections.

  Two of the four light receiving elements that face each other across the boundary line and two that face each other across the cross boundary line can be used as examples of pairs. Since the in-phase signal is the intensity information and the reverse-phase signal is the optical distance information, the intensity and the optical distance information can be separated from each other as described above. According to this claim, it is possible to adopt a light receiving element that is smaller and lower in cost, and even with a small amount of phase information received by this small light receiving element, the measurement unit can obtain the necessary measurement value. Can be obtained.

  On the other hand, as in claim 4, the scanning element is a two-dimensional scanning element that scans irradiation light in two directions orthogonal to each other, and the object to be measured is scanned by at least one of the two directions. It is conceivable that the irradiated light is modulated. Furthermore, as in claim 5, it is conceivable that a controller is connected to the scanning element, and the controller operates the operation of the scanning element to adjust the scanning speed and the scanning range. In this way, not only a two-dimensional image can be simply obtained, but it is possible to measure in an arbitrary modulation amount and in an arbitrary range simply by changing the setting of the controller.

  According to the sixth aspect, the measurement unit converts the AC component of the signal photoelectrically converted by the light receiving element into digitized data, and changes the addition amount of the data to obtain the measurement value for the measurement object. The range to obtain can be adjusted. According to the present invention, if sampling is performed at a frequency higher than the resolution of the optical system, random noise can be reduced, and the accuracy of measurement data of intensity and optical distance can be improved. In addition, since the scanning speed is constant, the display area of the image can be substantially changed by adjusting the addition amount.

  From the above, it is possible to accurately quantify information on the strength and optical distance inherent in the measurement object. The measured values of the intensity and the optical distance are obtained by calculating the direct current component of the sum signal and the difference signal of two light receiving elements each located on both sides with the direction perpendicular to the optical axis direction of the irradiation light as a boundary line. And the magnitude of the AC component and the phase signal of the AC component.

  Since the limit of the lateral resolution of the optical system is the upper limit of the detectable frequency, it is a frequency sufficiently higher than the upper limit frequency for digitizing data, and AC and DC components are converted to optical resolution. It is conceivable to sample at a corresponding frequency or higher. Random noise generated electrically or optically can be reduced by adding data flowing in time series based on the sampled data. As a result, it is possible to reduce the accuracy of measurement data and noise in the display of a three-dimensional image.

  In addition, since the scanning speed is constant, by changing the number of data to be added, the field of view range can be enlarged and reduced without changing the optical resolution, and the range in which the image is displayed can be changed substantially. . Therefore, it is possible to express the field of view range to some extent without substantially changing the NA of the objective lens used for irradiation.

  Further, as in claim 7, if the measurement object reflects the irradiation light when the irradiation light passes through the measurement object, the light receiving element of claim 1 receives the reflected light and photoelectrically Will be converted. In this case, by arranging a beam splitter in the optical axis between the light source and the measurement object, the beam splitter reflects and returns the irradiated light reflected by the measurement object to the light receiving element side. be able to. Further, as in claim 8, if the irradiation light passes through the measurement object when the irradiation light passes through the measurement object, the light receiving element according to claim 1 arranged on the optical axis, for example, The transmitted light is received and photoelectrically converted.

  In the reflection and transmission described above, the intensity information and the optical distance information are completely separated to calculate the reflectance, transmittance, and absorptance, or the optical distance, which is the product of the refractive index difference and the thickness, is calculated as the refractive index. It becomes possible to separate into a difference and thickness.

  On the other hand, in claim 9, one light receiving element is located on each side of the boundary line that is the transmission side and the reflection side of the measurement object, and at least each of the irradiation light modulated via the measurement object The light receiving element receives light from the two light receiving elements, and the measurement unit to which signals are input from these light receiving elements obtains the measurement value for the measurement object. If it does in this way, it will become the form which used together the reflective optical system and the transmission optical system so that irradiation light permeate | transmits and reflects a measurement target object through a measurement target object.

  In other words, by using a reflection optical system and a transmission optical system together, at least two signals from a total of four light receiving elements are compared, intensity information and optical distance information are acquired, and reflectance and transmittance are simultaneously obtained. Since they can be measured, the light absorption rate can be measured from these amounts. In particular, the intensity information and the optical distance information from the same location can be obtained simultaneously as the reflectance and transmittance values are obtained simultaneously from the same location by scanning the irradiation light. For this reason, there is no influence of pixel misalignment and the like, so that accurate transmittance, reflectance, and absorptance can be obtained with high resolution.

As described above, in the optical measurement device of the present invention, the coherent irradiation light is irradiated from the light source, and the scanning element scans the irradiation light and sends it to the measurement object as a scanning beam. Modulate light.
Further, after obtaining a non-modulated signal and a modulated signal photoelectrically converted by each of the light receiving elements located on both sides with the direction perpendicular to the optical axis direction of the irradiated light as a boundary line, at least two light receiving elements Process each other's signal. Thus, it is possible to obtain intensity information and phase information of the measurement object, and accordingly, it is possible to calculate a quantitative intensity, an optical distance, and the like.

It is a block diagram of the apparatus of the reflective optical system used as Example 1 of the optical measuring device which concerns on this invention. It is explanatory drawing showing the light irradiation area | region on the light receiving element of the reflective optical system of FIG. It is a perspective view explaining the repeated scanning of a laser beam. FIG. 4A is a graph showing a cutoff frequency of an MTF curve at a spatial frequency obtained by the light receiving element of Example 1, FIG. 4A shows the contrast of the intensity part, and FIG. 4B shows the phase part. Show contrast. It is a block diagram of the apparatus of the transmission optical system used as Example 2 of the optical measuring device which concerns on this invention. FIG. 10 is a block diagram of a transmission optical system apparatus which is a modification of the second embodiment. It is explanatory drawing showing the light irradiation area | region on the light receiving element of the apparatus made into Example 3 of the optical measuring device which concerns on this invention. It is the schematic showing the optical system of Example 4 of the optical measuring device which concerns on this invention. It is a block diagram of the apparatus which used together the reflective optical system used as Example 5 of the optical measuring device based on this invention, and a transmissive optical system. FIG. 10A is a diagram showing a screen displaying intensity information of the transmission optical system of the measurement object, FIG. 10A is a screen displaying the intensity information of the transmission optical system, and FIG. 10B is FIG. ) Is reduced to display four images. It is a figure which shows the screen which displayed the intensity | strength information of the transmission optical system of a measuring object, Comprising: FIG. 11 (A) is a screen which displays the intensity information of a transmission optical system, FIG.11 (B) does not change the resolution. The screen displays only four parts for displaying the image of FIG.

  Embodiments 1 to 5 of the optical measuring device according to the present invention will be described below in detail with reference to the drawings.

  A first embodiment of the optical measuring device according to the present invention will be described below with reference to FIGS. In this embodiment, the apparatus is a reflection optical system that reflects a scanning beam by a measurement object. FIG. 1 is a block diagram illustrating a configuration of a reflection optical system according to an embodiment.

  As shown in FIG. 1, a laser light source 21 that is a light source that emits (emits) laser light, which is coherent irradiation light, and a collimator lens 22 that has been corrected for aberrations so that parallel light can be obtained from the laser light. And are arranged in order. Therefore, in this embodiment, the laser light emitted from the laser light source 21 is converted into parallel light by the collimator lens 22.

  The collimator lens 22 includes a pupil transfer lens system 25 including two groups of lenses, a two-dimensional scanning device 26 that is a two-dimensional scanning element for two-dimensionally scanning the input laser light, and the input laser light. Beam splitters 27 that are originally for separating and emitting the light beams are arranged in order. As shown in FIG. 1, the optical path of the laser beam toward the pupil transfer lens system 25 is the optical axis L. The two-dimensional scanning device 26 is connected to a controller 23 which is a control means for changing a scanning range for two-dimensional scanning with laser light, a voltage for adjusting a scanning speed, and the like.

  Further, adjacent to the beam splitter 27, a pupil transmission lens system 30 composed of two groups of lenses is located, and an objective lens 31 is arranged next to the object G1 for measurement. That is, these members are also arranged along the optical axis L. As described above, the laser beam is irradiated onto the measuring object G1 along the optical axis L through the pupil transmission lens system 25, the two-dimensional scanning device 26, the beam splitter 27, the pupil transmission lens system 30, and the objective lens 31 in this order. The At this time, due to the operation of the two-dimensional scanning device 26, the laser beam becomes a scanning beam and is scanned two-dimensionally on the measurement object G1.

  On the other hand, a light receiving element group 29 composed of a plurality of optical sensors is arranged in a direction perpendicular to the direction in which the optical axis L passes and adjacent to the beam splitter 27. The scanning beam reflected by the measurement object G1 shown in FIG. 1 becomes diffracted light, and returns to the parallel light in the order of the objective lens 31, the pupil transmission lens system 30, and the beam splitter 27. Accordingly, the light is reflected by the beam splitter 27 and is incident on the light receiving element group 29 along the optical axis L of the irradiation light orthogonal to the original optical axis L.

  The light receiving element group 29 is not only arranged on the far field (far field) surface of the measuring object G1, but is composed of two light receiving elements 29A and 29B in this embodiment. However, as shown in FIG. 2, these are on a plane substantially perpendicular to the direction along the optical axis L, which is the center of the spot of the scanning beam LA, with a boundary line S passing through the optical axis L interposed therebetween. Light receiving elements 29A and 29B are arranged respectively. That is, the light receiving element 29A is positioned so as to be shifted to one side of the boundary line S, and the light receiving element 29B is positioned so as to be shifted to the opposite side of the boundary line S. The light receiving elements 29A and 29B receive LA.

Further, each of the light receiving elements 29A and 29B has a structure having a photoelectric conversion section (not shown), and each of the light receiving elements 29A and 29B receives the scanning beam LA and performs photoelectric conversion.
The above-described controllers 23 that operate the light receiving elements 29A and 29B and the two-dimensional scanning device 26 are connected to a signal comparator 33, respectively. Along with this, the signal comparator 33 obtains the intensity information and phase information of the measurement object G1 from the signals from the light receiving elements 29A and 29B and the signal from the controller 23. The signal comparator 33 is connected to a data processing unit 34 that finally processes data and obtains a measured value such as a profile of the measurement object G1. For this reason, in the present embodiment, the signal comparator 33 and the data processing unit 34 are set as measurement units.

  The laser light source 21 is a semiconductor laser and generates coherent laser light. The laser light is converted into a parallel light beam by the collimator lens 22 and is incident on the pupil transfer lens system 25. At this time, the incident beam diameter of the laser light is optimized using a diaphragm mechanism (not shown) or the like in consideration of the pupil transmission lens system 25.

  Here, the pupil transmission lens system 25 disposed between the collimator lens 22 and the two-dimensional scanning device 26 transmits the position of the exit surface of the collimator lens 22 to the next two-dimensional scanning device 26 in a conjugate manner. This is an optical system. The laser light that has passed through the pupil transmission lens system 25 is sent as a scanning beam to the beam splitter 27 via the two-dimensional scanning device 26, and the scanning beam from the beam splitter 27 is transmitted to the pupil of the objective lens 31. The light enters the objective lens 31 through the pupil transmission lens system 30 that is conjugated to the position.

  As described above, in this embodiment, the laser light in an unmodulated state is irradiated from the laser light source 21, but the laser light converted into a scanning beam by the two-dimensional scanning device 26 is incident on the measurement object G1 to form a pattern. The light is substantially modulated by the intensity change and the optical distance change, and is reflected by the measurement object G1, and finally the modulation signal of the Fourier transform pattern of the scanning beam is detected by the light receiving element group 29.

  As shown in FIG. 3, the two-dimensional scanning device 26 scans the measurement object G <b> 1 while moving the optical axis L by repeating laser light along the horizontal direction X. However, two-dimensional scanning can be performed by sequentially changing the scanning position along the vertical direction Y as indicated by 1, 2, 3, 4... In FIG. The controller 23 that adjusts the operation of the two-dimensional scanning device 26 can change the visual field range of the apparatus. That is, the controller 23 can freely enlarge or reduce the three-dimensional image by changing the voltage for controlling the horizontal scanning range of the two-dimensional scanning device 26 or changing the vertical scanning range. Can be adjusted. At this time, the controller 23 can change only the visual field range while keeping the lateral resolution constant.

  Therefore, according to the present embodiment, as shown in FIG. 3, the surface of the measurement object G1 has irregularities such that the convex portion C exists, or there is a light and shade such that the high-density portion D exists. Even in this case, the convex portion C and the high-density portion D can be accurately reproduced by the change in the diffraction amount and the reflection amount of the laser light scanned and irradiated by the two-dimensional scanning device 26.

In this way, the laser light which is not modulated is emitted from the laser light source 21, but this laser light which is converted into a scanning beam by scanning by the two-dimensional scanning device 26 is substantially diffracted through the measurement object G1. Diffracted light. Of this diffracted light, the 0th-order diffracted light and the 1st-order diffracted light themselves are unmodulated light, and the intensity signals of these diffracted lights are unmodulated signals.
On the other hand, the portion where the 0th-order diffracted light and the 1st-order diffracted light overlap is a modulated intensity signal because the 1st-order diffracted light has a phase difference with respect to the 0th-order diffracted light. This is because each of the intensity or optical distance can be regarded as an aggregate of a certain spatial frequency, and the overlapping portion of the 0th-order diffracted light and the 1st-order diffracted light by scanning of the beam that is the irradiation light is the spatial frequency corresponding to the 1st-order diffracted light Modulated with.

  The modulated light is converted as an intensity signal into a current having a frequency corresponding to the spatial frequency by the light receiving elements 29A and 29B, and this current is converted by a current-voltage conversion circuit of a photoelectric conversion unit in the light receiving elements 29A and 29B. Convert to voltage. Accordingly, the zero-order diffracted light and the first-order diffracted light themselves that are unmodulated light are DC signals, and the overlapping portion of the zero-order diffracted light and the first-order diffracted light that are modulated light is an AC signal.

  Next, how signals detected by the light receiving elements 29A and 29B will be specifically described below. The signal processing is the same not only in the reflection optical system but also in the transmission optical system and also in the transmission optical system with high resolution, and will be described collectively in the following embodiments.

The state of the measurement object G1 is generally represented by the product of the intensity pattern and the optical distance pattern, and the irradiation light is diffracted by the measurement object G1.
For simplicity, the complex amplitude E ₀ of the intensity pattern is a cosine wave pattern with a pitch di, and the phase Θ of the optical distance pattern is a sine wave pattern with a pitch dp. When the wavelength of the irradiation light is λ, the intensity modulation degree is m, the refractive index difference between the medium and the measurement object is δn, and the thickness is h, it can be expressed as the following formula.

These patterns are irradiated with light having a wavelength λ and received by light receiving elements 29A and 29B arranged on a Fourier transform plane which is a far field. In the Fourier transform plane of the complex amplitude E ₀ of the intensity pattern in the pattern of the measurement object G1 in the amplitude portion, a region on one side with respect to the optical axis L and where the first-order diffracted light and −1st-order diffracted light do not overlap, that is, spatial frequency. When a region having a relatively high value is considered, the following formula is obtained on the first-order diffracted light side.

  Similarly, on the Fourier transform plane of the phase portion, a portion on one side with respect to the optical axis and having a relatively high spatial frequency where the first-order diffracted light and the −1st-order diffracted light do not overlap is considered. On the first-order diffracted light side, a portion having a relatively high spatial frequency is given by the following formula.

Therefore, on the first-order diffracted light side, the light amplitude distribution E _R is expressed by the following formula.

Here, a represents the phase information of the optical distance, and b represents the ratio of the first-order Bessel function and the zero-order Bessel function of the phase information of the optical distance. As described above, m represents the intensity modulation degree. Thus, the output I _R of the amount of light received by the first-order diffraction light side can be determined by the following equation.

Similarly, consider a portion having a relatively high frequency on one side with respect to the optical axis L and where the first-order diffracted light and the −1st-order diffracted light do not overlap. On the −1st order diffracted light side, the light amplitude distribution E _L is expressed by the following equation.

Thus, the output I _L of amount of light received by the -1-order diffraction light side is represented by the following formula.

In consideration of the possibility of a slight difference in circuit gain between the first-order diffracted light side and the −1st-order diffracted light side, signal levels A ₁ and A detected by inserting coefficient values K ₁ and K ₂ are considered. _{The two} were generalized with differences.

As described above, the strength portion is in phase and the phase portion is in reverse phase.
Although details are omitted, when the light receiving element that receives light in the same area as the NA of the objective lens with the optical axis L as a boundary is used, the spot diameter is smaller than the spot diameter on the measurement target G1. For the same spatial frequency as the magnitude, the above equation is obtained.

  As shown in the graph of FIG. 4, the dotted line T indicates a frequency that is half the cutoff frequency of the MTF curve M at the above-described spatial frequency. That is, the contrast of the intensity portion shown in FIG. 4A is half the maximum value as shown by the dotted line T, and the contrast of the phase portion shown in FIG. The same value as the value. At spatial frequencies other than these, the MTF curve M of the intensity portion is as shown in FIG. 4A, and the MTF curve M of the phase portion is as shown in FIG. 4B.

Therefore, the values of m and b to be obtained in the following discussion are for a frequency that is half the cutoff frequency of the spatial frequency.
On the other hand, in the application of Japanese Patent Application Laid-Open No. 2015-4643, the inventors of the present application specify means for correcting the MTF by specifying the spatial frequency of the measurement object G1 from the frequency information obtained by photoelectric conversion using beam scanning. Has proposed. By using this method, if the actual values of m and b are corrected, the optical distance information can be obtained via the intensity modulation m and b inherent in the measurement object G1.

  Now, when the scanning beam is scanned at a speed v, a modulation signal corresponding to the spatial frequency is placed on the scanning beam. Therefore, when θ and η are detected frequencies as fi and fp, respectively, Can be expressed as That is, the phase of the spatial frequency is modulated as follows.

Next, a signal obtained from each of the first-order diffracted light and the −1st-order diffracted light by each light receiving element is used as a first signal. And At this time, the second signal subjected to the first Hilbert transform is represented by H1 (I _R ) or H1 (I _L ), and the third signal subjected to the second Hilbert transform is represented by H2 (I _R ) or H2 (I _L ). It shall be expressed as Then, the output obtained by the light receiving element on the first-order diffracted light side and the Hilbert transform of the signal obtained by the light-receiving element on the −1st order diffracted light side are given by

Here, the first output of the current signal I _R and the current signal I _L and the sum of the Hilbert transformed third signals H 2 (I _R ) and H 2 (I _L ) are output first. When the DC outputs of the current signals I _R and I _L are taken out, the following is obtained.

Division by this signal allows normalization.
That is, α is set to α = 2b / (1 + b ² ), and β is set to β = 2m / (1 + m ² ).

The first signal which is the current signals I _R and I _L of the output values received on the first-order diffracted light side and the −1st-order diffracted light side, and the third signal H 2 (I _R ) and H 2 (I _L ) which are Hilbert transformed. Are as follows: Note that θ ₀ corresponds to η, and θ ₁ corresponds to θ.

Now, the amount of these converted one output and the other output I _R and -1 order diffracted light side of the light amount of which is an output first-order diffraction light side from the light receiving element from the light receiving element of the two light receiving elements each signal The sum signal and difference signal applied to the output I _L are as shown in the following equation.

  As described above, since the signals related to the intensity are in phase, when these ratios are taken, only the phase signal that is a signal of the optical distance is obtained as shown in the following equation (3).

  Further, when the ratio between the Hilbert transform of the difference signal and the two Hilbert transforms is taken, the following equations (4) and (5) are obtained.

Therefore, the phase θ ₀ with respect to the spatial frequency of the phase of the optical distance is obtained from the equation (4), and α is obtained from the equation (3). Since α is α = 2b / (1 + b ² ) and b = J1 (a) / J0 (a), b is calculated by solving a quadratic equation relating to b.
Since b is connected to a which is the maximum amplitude of the phase information of the optical distance through the 0th-order and 1st-order Bessel functions, a can be derived. Since b is an arbitrary value (value of b <1 and b> 1), it is selected appropriately. In particular, in the case of a transmission optical system, since the refractive index difference is very small, J0 (a)> J1 (a) is satisfied, and a solution of b <1 may be selected.
Actual phase information can be obtained from the following mathematical formula.

  Next, taking the ratio of the Hilbert transform of the sum signal and the two Hilbert transforms, the result is as follows.

Therefore, the phase θ ₁ with respect to the intensity spatial frequency is obtained from the equation (6), and β is obtained from the equation (7). β is β = 2b / (1 + b ² ), and m is calculated by solving a quadratic equation related to the intensity modulation degree m. In this case, the intensity modulation degree m is m <1, so there is only one solution.
Actual intensity information can be obtained from 1 + m cos θ (x = 0).

In addition, if C ₀ and C ₁ are measured by reflecting 100% with a mirror or the like, b is obtained in a state where the measurement object is present, and C ₀ and C ₁ are measured, m is effectively m. Can be obtained. In this way, it is possible to make a physical quantity such as reflectance.

  As described above, the light receiving elements 29A and 29B detect the scanning beam that has passed through the measurement object G1, thereby obtaining signals on both sides of the light receiving region divided into two, and using this, the intensity information is obtained from both light receiving elements. The fact that the outputs are in phase and the fact that the phase information, which is optical distance information, is out of phase between the outputs of both light receiving elements are used. Then, it becomes possible to completely separate the intensity information modulation signal and the optical distance information phase signal by using the original signal and the signal that has undergone the Hilbert transform once and the signal that has passed twice.

  Accordingly, the signal comparator 33 compares the signal photoelectrically converted by the light receiving elements 29A and 29B with the signal from the controller 23, finally processes the data, and the data processor 34 performs the above-described calculation. Thus, it is possible to obtain measurement values such as the degree of modulation of the optical distance information and the intensity information of the measurement object G1. Note that the Hilbert transform need not be used as long as the calculation can substantially separate the product of the in-phase signal and the anti-phase signal including the DC signal and the AC signal.

That is, the intensity information of the measuring object G1 is obtained by the signal that the signal comparator 33 photoelectrically converts the scanning beam reflected by the measuring object G1 and the signal that instructs the scanning of the controller 23 that is the basis of the scanning beam. The phase information is obtained, and the intensity information and the phase information are sent to the data processing unit 34 including a CPU and a memory connected to the signal comparator 33.
Accordingly, the data processor 34 records the intensity information and the phase information together with the scanning information for the plane, and easily derives the measured values of the phase information such as the intensity information and profile information about the surface of the measurement object G1. be able to. In this case, the above-described intensity information is information that reflects the reflectance.

  As described above, according to the present embodiment, the measurement object absorbs light, has intensity information with different reflectance and transmittance, and has optical distance information with different refractive index distribution and thickness. Even if it does, it becomes possible to provide the apparatus which isolate | separates both intensity | strength information and optical distance information correctly.

Accordingly, if such an optical system and signal processing of this embodiment are used, each time two-dimensional scanning is performed, three-dimensional measurement data is acquired as optical distance information, and simultaneously from the three-dimensional measurement data. It is possible to obtain the intensity information separately. For this reason, according to the optical system of this embodiment, the state change of cells and microorganisms, and the transient state change of the surface state and internal state of these cells etc. accompanying this state change can be observed and measured at high speed. Information such as transmittance, reflectance, and absorptance can be acquired at the same time.
Furthermore, it is possible to display a 3D stereoscopic image by using an autostereoscopic display that has been commercialized based on optical distance information or a 3D display using polarized glasses. Can be a useful device.

  In this optical system, the example using one two-dimensional scanning device 26 shown in FIG. 1 has been described. However, if the application requires simple data in only one direction, this two-dimensional scanning device is used. The same effect can be obtained even if it is replaced with a one-dimensional scanning device. As these one-dimensional scanning devices, galvanometer mirrors, resonant mirrors, rotating polygon mirrors, and the like can be employed.

  Also, instead of one two-dimensional scanning device 26, two independent one-dimensional scanning devices for X direction and Y direction orthogonal to each other are prepared and arranged before and after the pupil transmission lens system 25. By doing so, the same function as the two-dimensional scanning device 26 can be realized. For example, a micromirror device using a micromachine technique may be used. As this micromirror device, both one-dimensional and two-dimensional devices are known and commercialized. Furthermore, one one-dimensional scanning device and a table (not shown) that supports the measurement object G1 can be used in a form orthogonal to each other.

  As described above, based on the signal photoelectrically converted by the light receiving element group 29 of the scanning beam and the signal serving as a reference for scanning by the two-dimensional scanning device 26 from the controller 23, the intensity of the measurement object G1 is measured. The optical distance that is information and phase information can be calculated quantitatively.

Next, a second embodiment of the optical measuring device according to the present invention will be described below with reference to FIG. In the present embodiment, the apparatus is a transmission optical system in which a scanning beam passes through a measurement object.
FIG. 5 is a block diagram showing the transmission optical system according to the present embodiment. Since the main optical system is the same as that of the reflection optical system, a description thereof will be omitted. However, in this transmission optical system, the light collected by the objective lens 31 is compared with the first embodiment and the measurement object G2 is reflected. It will be transparent.

  In this embodiment, since it is a transmission optical system, the beam splitter 27 is not necessary, and a light receiving element group 29 is arranged at a position opposite to the objective lens 31 via the measurement object G2 in accordance with this. ing. However, as in the first embodiment, the light receiving element group 29 is not only arranged on the far field surface of the measurement object G2, but also has a structure similar to the two light receiving elements 29A and 29B in the first embodiment. 29E and 29F.

  That is, in the case of this apparatus of a transmission optical system, the light receiving element group 29 is arranged on an extension line of the optical axis L of the objective lens 31 as shown in FIG. Further, in the same manner as in the first embodiment, light is received with a boundary line S passing through the optical axis L on a plane substantially perpendicular to the direction along the optical axis L that is the center of the spot of the scanning beam LA. Elements 29E and 29F are located respectively. Therefore, the light receiving element 29E is located on one side of the boundary line S, and the light receiving element 29F is located on the opposite side of the boundary line S. As a result, the transmission optical system apparatus of FIG. 5 also has a spatially substantially equal phase on the light receiving element group 29 in the same manner as the reflection optical system apparatus of FIG.

  Further, the signal comparator 33 photoelectrically converts the scanning beam transmitted through the measurement object G2 described above and the intensity information of the measurement object G2 based on the signal instructing scanning of the controller 23 that is the basis of the scanning beam. The phase information is obtained, and the intensity information and the phase information are sent to the data processing unit 34 including a CPU and a memory connected to the signal comparator 33. Along with this, the intensity information and phase information are recorded together with scanning information for the plane by the data processing unit 34, and the measurement values of the phase information such as the intensity information and profile information about the surface or inside of the measurement object G2 can be easily obtained. Can lead to. In this case, the above-described intensity information is information that reflects the reflectance.

Accordingly, as in the first embodiment, the signal comparator 33 is obtained from the signals photoelectrically converted by the light receiving elements 29E and 29F constituting the light receiving element group 29 and the signal instructing scanning by the two-dimensional scanning device 26 from the controller 23. However, the intensity information and phase information of the measurement object G2 are obtained.
Then, as in the first embodiment, the original signal and the Hilbert transform are performed twice, so that the data is finally processed, and the data processing unit 34 determines the optical distance, transmittance, and transmission of the profile of the measurement object G2. Measurement values such as rate can be obtained substantially. As a result, also according to the present embodiment, it is possible to completely separate the intensity information from the transmitted light and the optical distance information.

Further, C ₀ and C ₁ shown in the above-described Example 1 are measured in a state where there is no measurement object, and b is obtained in the state where the measurement object G2 is present, and then C ₀ and C ₁ are measured. In effect, the intensity information related to the intensity modulation degree m can be obtained. In this way, this intensity information can be converted into a physical quantity such as transmittance.

  In particular, in the transmission optical system apparatus as in the present embodiment, the state change of a living cell that is unstained and non-invasive can be separated into intensity information and optical distance information and observed in real time. It can play a major role in testing whether cells such as cells are normal or testing for the presence of cancer cells. This is a feature that is greatly different from a measuring instrument such as an electron microscope that cannot be observed unless the living body is killed even at a high magnification.

  On the other hand, as a modification of the present embodiment, as shown in FIG. 6, the lens 40 is behind the measurement object G2 on the opposite side of the objective lens 31 with the measurement object G2 interposed therebetween and in front of the light receiving element group 29. It is possible to arrange. That is, the scanning beam, which is diffracted light from the measurement object G2, is converted into parallel light by the lens 40 and then guided to the light receiving element group 29. For this reason, in this modification, as shown in FIG. 6, the Fourier transform pattern of the scanning beam transmitted through the measurement object G <b> 2 is converted into parallel light by the lens 40 and received by the light receiving element group 29. However, the light may be condensed by the lens 40 and the scanning beam may be guided to the light receiving element group 29.

  For the purpose of improving the lateral resolution, an optical system tilted with respect to the optical axis L of the objective lens 31 is disposed, and a part of the 0th-order diffracted light and the 1st-order diffracted light having a high spatial frequency are arranged in the tilted optical system. JP-A-2013-238450 discloses a method for acquiring information up to a higher spatial frequency by superposition. Also in this method, since the MTF curve of the intensity information and the phase information is known in advance, it is possible to acquire the intensity information and optical distance information up to a higher spatial frequency.

  Furthermore, the inventors of the present application have already shown in Japanese Patent Application Laid-Open No. 2017-116925 that the MTF curve due to the spatial frequency can be corrected by detecting the frequency such as the voltage obtained by photoelectrically converting the spatial frequency in the scanning optical system. . By combining the technique disclosed in Japanese Patent Application Laid-Open No. 2017-116925 and the embodiment of the present application, the original information of the measurement objects G1 and G2 can be correctly converted into intensity information and optical distance information. It is possible to correct missing information. For this reason, it becomes possible to separate and measure intensity information and optical distance information with higher reliability.

  On the other hand, in the embodiment of the present application, since the frequency can be measured for each scanning pixel, it is possible to easily set the spatial frequency or the like that the observer observing the measurement objects G1 and G2 wants to emphasize, A part that is hidden can be displayed. As the spatial frequency can be changed easily and flexibly in this way, the spatial frequency band is divided into several parts, and the observer can set the gain manually in each band. A kind of equalizer can be performed freely.

Since the limit of the lateral resolution of the optical system is the upper limit of the detectable frequency, sampling is performed at a frequency sufficiently higher than the upper limit frequency, and data flowing in time series is added based on the sampled data. Thus, random noise can be reduced. As a result, the accuracy of measurement data is improved and noise is reduced when a three-dimensional image is displayed.
Furthermore, since the scanning speed is constant, it is possible to substantially change the image display range by changing the number of data to be added. Therefore, the field of view range can be arbitrarily enlarged or reduced to some extent without substantially changing the NA of the objective lens used for irradiation.

  That is, according to the present method, the intensity information and the optical distance information can be changed only in the visual field range while keeping the lateral resolution constant. Further, if the scanning element MEMS or the resonant mirror is used together with a function for changing the scanning range by changing the voltage for controlling the scanning range in the horizontal scanning direction, the three-dimensional image can be further freely enlarged and reduced. This can be done without changing the lateral resolution.

As described above, the intensity information and the optical distance information of the measurement object can be easily and completely separated and visualized by the signal based on scanning and the signals detected by the light receiving element 29E and the light receiving element 29F. And a measured value is computable by processing this signal appropriately.
Furthermore, by combining this method with a method that reproduces the spatial frequency inherent in the measurement object, intensity information such as reflectance, transmittance, and absorption rate and optical distance information of the measurement object can be calculated more accurately. You can also.

  In the case of a transmission optical system, visualization of cells, micro-organisms, and the like can be realized with a simple apparatus according to the above-described embodiment, so that it can be used as a micro three-dimensional digitizer in education and hobby. In this way, by using a combination of a recent three-dimensional printer and the apparatus according to the present embodiment, only the optical distance information without intensity information is used, and it remains alive without processing such as staining. In this state, the process of cell division and the three-dimensional stereoscopic image of the organ inside the cell of the micro-organism can be easily expressed as a three-dimensional model.

  Next, a third embodiment of the optical measuring device according to the present invention will be described below with reference to FIG. This embodiment can be applied to a reflection optical system apparatus and a transmission optical system apparatus.

  In the first and second embodiments, the light receiving elements 29A and 29B or the light receiving elements 29E and 29F constituting the light receiving element group 29 are on a plane substantially perpendicular to the direction along the optical axis L of the scanning beam LA. It is located in each of the two divided regions across the boundary line S passing through the optical axis L. On the other hand, in the present embodiment, the light receiving elements 29A to 29D divided into four parts shown in FIG. 7 are used so that each information can be acquired in the horizontal direction and the vertical direction in the plane of the measurement objects G1 and G2. .

  That is, the light receiving elements 29 </ b> A to 29 </ b> D are arranged in each region partitioned by the boundary line S and the intersection boundary line KS that intersects the boundary line S on the optical axis L of the irradiation light. And by acquiring each information of the horizontal direction and the vertical direction in the surface of the measuring objects G1 and G2 individually by these four light receiving elements 29A to 29D, more detailed data can be obtained.

  Furthermore, not only this but two things which oppose on both sides of boundary line S in these four light receiving elements 29A-29D (for example, light receiving element 29A and light receiving element 29B), and two which oppose on both sides of crossing boundary line KS. It is possible to obtain the intensity information and the optical distance information by the above-described calculation using two light receiving elements that are paired with each other (for example, light receiving element 29A and light receiving element 29C).

  Specifically, since the in-phase signal is the intensity information and the reverse-phase signal is the optical distance information, the intensity and the optical distance information can be separated from each other as described above. Along with this, it is possible to adopt a light receiving element that is smaller and less expensive, and the measurement unit can obtain a necessary measurement value even with a small amount of phase information received by this small light receiving element. In the present embodiment, the area is divided into four areas. However, the area may be divided into four or more areas and four or more light receiving elements may be employed.

Embodiment 4 of the optical measuring device according to the present invention will be described below with reference to FIG.
FIG. 8 is a schematic diagram showing the configuration of the optical measuring device of the present embodiment. In the present embodiment, in order to process the scanning beam transmitted through the measuring object G2 while improving the lateral resolution, for example, the inclined optical system shown in this figure is arranged in the lower part of the transmission optical system of the second embodiment. To do. In FIG. 8, the optical systems such as the pupil transmission lens systems 25 and 30, the two-dimensional scanning device 26, the signal comparator 33, and the data processing unit 34 are not shown, and instead of the light receiving element group 29, the light receiving elements 50 is adopted.

  In this embodiment, the lens 36 is inclined with respect to the optical axis of the 0th-order diffracted light that is the optical axis L of the objective lens 31. Specifically, a part of the 0th-order diffracted light and a part of the 1st-order diffracted light transmitted through the measurement object G2 are intermediate between the optical axis L of the 0th-order diffracted light and the optical axis L1 of the 1st-order diffracted light. The lens 36 is tilted by the optical axis L3 having an inclination angle. As a result, not only a part of the 0th-order diffracted light but also a part of the 1st-order diffracted light having a higher spatial frequency compared with the case where the same lens is used are taken in by the imaging optical system. Interference between the folded light and the first-order diffracted light is realized. Although not shown, in the present embodiment, a similar optical system is disposed at a target position with respect to the optical axis L.

  Further, in this embodiment, the lens 36 is tilted to acquire a part of the 0th-order diffracted light and a part of the 1st-order diffracted light, and the diffracted lights that have been converted into parallel light beams by the lens 36 are collected by the lens 52. The lens 52 causes the diffracted lights to overlap in the vicinity of the focal point and substantially interfere. However, since it is not interference between the 0th-order diffracted light and the ± 1st-order diffracted light, it is different from the imaging of the measurement object G2 itself.

  On the other hand, in the present embodiment, the pitch of the interference fringes can be widened by increasing the effective focal length of the lens 52 or arranging the light receiving element 50 at a slightly defocused position. If the focal lengths of the lens 36 and the lens 52 are the same, it is naturally the same magnification and becomes the spatial frequency of the measurement object G2. On the other hand, the result of interference by the optical system of −1st order diffracted light, which is the other optical system (not shown), is an interference fringe with a shifted pitch. However, if the light receiving element is larger than the pitch of the interference fringes, it is difficult to align the element that receives ± first-order diffracted light.

  Therefore, by magnifying the interference fringe itself by the magnifying optical system 53 and making it approximately equal to the size of the light receiving element 50 or slightly defocused, the intensity information becomes in-phase between the ± first-order diffracted lights, The phase information, which is optical distance information, is naturally opposite in phase, so that the contrast is reversed in such a way that the 0th-order diffracted light becomes a bias. In this way, information can be obtained very easily up to a region having a high spatial frequency, and both intensity information and optical distance information can be obtained by performing the above-described calculation. This makes it possible to measure highly reliable intensity information and optical distance even for a measurement object G2 that requires a high lateral resolution. In this embodiment, since the lens 52 is used, a wavefront aberration that allows the phase difference between the 0th-order diffracted light and the 1st-order diffracted light incident on the lens 52 to be reflected as it is is allowed. Therefore, there is no need to use an expensive lens. Further, although not described in detail, the magnifying optical system 53 may be omitted, and the light receiving element 50 may be disposed at a defocus position shifted from the focus of the lens 52. At this time, the contrast of the interference fringes can be lowered by the wavefront distortion of the second-order wavefront, and the effect of superimposing the 0th-order diffracted light and the other diffracted light can be brought about.

Here, a method of adjusting the light receiving element will be specifically described.
When the information on the measurement object G2 is phase information, adjustment is performed in two systems, that is, between the first-order diffracted light and the 0th-order diffracted light and between the −1st-order diffracted light and the 0th-order diffracted light. That is, the light receiving element is adjusted so that when the one light receiving element has the maximum light amount, the other light receiving element becomes almost zero.
Further, when the information on the measurement object G2 is intensity information, the adjustment is similarly performed in two systems between the first-order diffracted light and the zeroth-order diffracted light and between the −1st-order diffracted light and the zeroth-order diffracted light. To do. In this case, the light receiving element is adjusted so that when one of the light receiving elements has the maximum light amount, the other light receiving element also becomes maximum.

  In this embodiment, even if the lenses have slightly different focal lengths, the light amounts received by the light receiving elements are not significantly changed, and if the wavefront aberration in the lens surface is not large, the pitch of the interference fringes changes somewhat. It can be used as it is. Moreover, the limit of the spatial frequency that can be acquired is about 1.5 times. Since this optical system is constructed using only the lens system, it is very simple and resistant to disturbance.

  Furthermore, in this embodiment, each light receiving element is located on either side of the boundary line, but the light receiving element may be disposed across the boundary line. Even in this case, it is only necessary that the light receiving element is positioned so as to be shifted to one side of the boundary line.

  As mentioned above, although each Example concerning this invention was described, this invention is not limited to each above-mentioned Example, A various deformation | transformation can be implemented in the range which does not deviate from the meaning of this invention.

Embodiment 5 of the optical measurement apparatus according to the present invention will be described below with reference to FIG.
FIG. 9 is a schematic diagram showing the configuration of the optical measuring device of the present embodiment. This embodiment can be applied to an apparatus that acquires intensity information and optical distance information by using a reflection optical system and a transmission optical system in combination.

  As shown in FIG. 9, in the present embodiment, as in the first embodiment, in addition to the light receiving element group 29 configured by two light receiving elements 29A and 29B of the reflection optical system, the objective lens 31 via the measurement object G2 is provided. And a light receiving element group 29 of a transmission optical system composed of two light receiving elements 29E and 29F disposed at the same position as in the second embodiment. In the present embodiment, the other parts have substantially the same structure as that of the first embodiment. In addition to the light receiving elements 29A and 29B being connected to the signal comparator 33, two light receiving elements 29E as shown in FIG. , 29F are also connected to the signal comparator 33, respectively.

  Therefore, the signal comparator 33 compares the signals from the four light receiving elements 29A, 29B, 29E, and 29F and uses the reflection optical system and the transmission optical system together to obtain intensity information and optical distance information. Will get.

  That is, by using the reflection optical system and the transmission optical system in combination, the reflectance and the transmittance can be measured at the same time, so that the light absorptance can also be measured from these measured values. In particular, the intensity information and optical distance information from the same location can be obtained as the reflectance and transmittance values are obtained simultaneously from the same location by scanning the irradiation light. For this reason, since there is no influence of pixel misalignment or the like as compared with a case where images acquired by a transmission optical system and a reflection optical system using a CCD or the like are compared, the transmittance, reflectance, and absorptance are accurately and accurately determined. It can be obtained with high resolution.

The present embodiment relates to image display obtained from these light receiving elements, and for example, with respect to FIG. 10A, which is a screen displaying intensity information K of the transmission optical system of the measurement object G2. For example, four images can be displayed by switching as shown in FIG. As a result, a plurality of different images having different qualities, for example, four can be displayed simultaneously.
For example, in combination with any one of the examples of the polarized image shown in Japanese Patent Application Laid-Open No. 2017-133867 previously filed by the present inventors, an image of the optical distance and intensity of the reflective optical system, which is a total of four images. In addition, images of the optical distance and intensity of the transmission optical system may be displayed, respectively.

On the other hand, in the example of FIG. 10B, the entire data is displayed by thinning out the data, but the resolution of the image G of the measurement object G2 remains unchanged as shown in FIGS. 11A to 11B. Thus, only the required part GP in the frame part P of FIG.
As described above, in the example shown in FIG. 10B, there is an advantage that it is possible to roughly determine a portion having a different quality in the whole image shown in FIG. 10A of the measurement object G2, and the example shown in FIG. Then, there is an advantage that it is possible to observe and measure the part to be watched without reducing the resolution.

The optical measurement apparatus of the present invention can measure not only the distance to the measurement object sample and the shape of the sample, but also separates the intensity information from the optical distance information, so that the reflectance, transmittance, absorption rate, etc. It is also possible to measure the physical quantity. Thus, it can be applied to various types of measuring instruments such as a microscope.
The optical measuring device of the present invention can be applied not only to a microscope but also to various types of optical instruments and measuring instruments using electromagnetic waves having waves, and the strength of these optical instruments and measuring instruments using electromagnetic waves having waves. And 3D profile information such as height can be separated.

21 Laser light source
22 collimator lens 23 controller 25 pupil transfer lens system 26 two-dimensional scanning device (scanning element, two-dimensional scanning element)
27 Beam splitter 29 Light receiving element group 29A to 29F Light receiving element 30 Pupil transmission lens system 31 Objective lens 33 Signal comparator (measurement unit)
34 Data processing unit (measurement unit)
G1, G2 Measuring object L Optical axis LA Scanning beam S Boundary line KS Crossing boundary line

Claims (9)

A light source that emits coherent illumination light;
A scanning element that scans irradiation light from a light source and sends it to a measurement object;
At least two light receiving elements that are respectively positioned on both sides with a direction perpendicular to the optical axis direction of the irradiation light as a boundary line, and that respectively receive the irradiation light modulated by the measurement object in accordance with scanning and photoelectrically convert the irradiation light; ,
A non-modulated signal, which is a direct current component, and a modulated signal, which is an alternating current component, are extracted from each signal photoelectrically converted by the light receiving element, and intensity information and phase information of the object to be measured are obtained using the non-modulated signal and the modulated signal. And obtaining a measurement value for the measurement object based on the intensity information and the phase information,
An optical measuring device. The signal photoelectrically converted by each of the two light receiving elements is a first signal,
Using the second signal obtained by Hilbert transform of the modulation signal of the AC component and the third signal obtained by further Hilbert transforming the second signal,
The optical measurement apparatus according to claim 1, wherein each of the converted signals is applied to a sum signal and a difference signal of an output from one of the two light receiving elements and an output from the other light receiving element.   3. The device according to claim 1, wherein the light receiving element is located in a region defined by an intersection boundary line intersecting the boundary line on the optical axis of the irradiation light and the boundary line. The optical measuring device described in 1.   The scanning element is a two-dimensional scanning element that scans the irradiation light in two directions orthogonal to each other, and the irradiation light irradiated onto the measurement object is modulated by scanning in at least one of the two directions. The optical measuring device according to any one of claims 1 to 3.   The optical measurement apparatus according to claim 1, wherein a controller is connected to the scanning element, and the controller operates a scanning element to adjust a scanning speed and a scanning range.   The measurement unit adjusts a range in which a measurement value for a measurement object is obtained by changing the amount of addition of the data into digital data of an AC component of a signal photoelectrically converted by the light receiving element. The optical measuring device according to any one of claims 1 to 5. A beam splitter is disposed between the light source and the measurement object,
The beam splitter reflects the irradiation light reflected from the measurement object and returned from the measurement object, so that the light receiving element receives the irradiation light passing through the measurement object. An optical measuring device according to claim 1.   The optical measurement device according to claim 1, wherein the light receiving element receives irradiation light passing through the measurement object by passing through the measurement object.   At least two light receiving elements each of which are arranged to receive irradiation light modulated via the measurement object, each of the light receiving elements being located on both sides of the boundary line, which are the transmission side and the reflection side of the measurement object, respectively. The optical measurement apparatus according to claim 1, wherein the measurement unit that receives the light and receives a signal from these light receiving elements obtains a measurement value of the measurement object.

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