JPH04280388A - Optical scanner - Google Patents

Abstract

PURPOSE: To easily aim a mark with the beam of a laser diode, to exactly position the mark for a laser scanner before scanning, and to exactly trace the mark by the laser scanner during scanning. CONSTITUTION: A laser for generating an incident light beam is provided in a head 10 for aiming a mark by a hand scanning head 10, and an optical element such as a positive lens for directing the incident laser beam along a first optical path to the reference plane of a plane perpendicular to an incident laser beam transmitting direction 104 is provided in the head 10 (which is provided also in a blocking wall part 58). The laser light reflected from a mark is going along a second optical path going away from the mark to the head 10. A reflection surface such as a scanning mirror 66 is vibrated back and force, and the mark is scanned. The head 10 is provided with a sensor means 80 for generating an electric analog signal indicating the optical intensity of the reflected laser light, and signal processing means 81-83 which process an electric signal, and process the data of an scanned mark into a digital electric signal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical scanning device for optically scanning a symbol, such as a bar code symbol, which has portions having different light reflectivity. A multimodal, portable optical scanning device that can be held by a user and aimed at each symbol to be read, wherein a first mode of operation is used for aiming or reading, and a second mode of operation is used for aiming or reading. The mode of operation concerns the optical scanning device used to read each symbol.

0002

2. Description of the Related Art Until now, optical readers and optical scanning devices have been used to optically read symbols, such as barcode symbols, provided on objects to identify them by optically reading them. Various types have been developed. A barcode symbol itself consists of a series of bars of varying widths,
spaced apart from each other to delineate areas of varying widths.
A coded pattern is formed in which the bars and regions have different light reflectivity. This reader and optical scanning device reads the coded pattern by
Electro-optically decoded into an alphanumeric digit representation of the object. This type of scanning device is disclosed, for example, in U.S. Pat. No. 4,251,798, U.S. Pat.
Specification No. 9,361, Specification No. 4,387,297, Specification No. 4,409,470, Specification No. 4,4
It is disclosed in the specification No. 60,120, the specification No. 4,835,374, etc.

[0003] As disclosed therein, particularly preferred embodiments of these scanning devices emit a laser light beam from a portable laser scanning head held by a user; , a laser light beam is aimed at the symbol to be read, each scans the laser light beam across the symbol, detects the scanning beam of laser light reflected from the symbol, and decodes the detected reflected light. Ta. Typically, but not always, the laser light beam is produced by a helium-neon gas laser that produces red laser light at a wavelength of approximately 6328 angstroms so that the red laser light is visually perceptible to the user. , so the user can, without difficulty,
The head can be aimed as desired and the emitted red laser light can be positioned and held over and across the symbol during scanning.

However, the laser light beam is
Specification No. 4,409,470, No. 4,460,12
As disclosed in the specification of No. 0, etc., when the laser light is generated by a semiconductor laser diode, the laser light that cannot be visually recognized by the user is emitted from the laser diode, and when the laser light is emitted from the laser diode, the head of the symbol Aiming was more difficult. Some diodes emit laser light with a wavelength of about 7800 angstroms, which is very close to infrared light and borderline visually perceptible. Even when using a laser diode that generates light in the visible light range, the laser diode light tends to be masked by surrounding light. Furthermore, it is particularly useful when the laser diode light is moving, for example by being scanned across the symbol, on the order of multiple times per second, e.g. 40 times per second.
When the laser diode light is being scanned at high speeds, such as when scanning at a speed of Ta. Therefore, the wavelength of the laser light, the intensity of the laser light, the intensity of ambient light in the environment in which the laser light is operated, the scanning speed, and other factors.
Or, due to two or more factors, the laser diode light could not be easily recognized visually.

[0005] As described above, since the laser diode light cannot be easily recognized visually, the user cannot easily see the laser diode light.
It was not easy to aim the laser diode light at the symbol and required considerable difficulty and effort. Therefore, through trial and error, the user searches for and scans the laser diode light until it finally appears on the symbol.
Across this, information from the scanning device that the symbol desired to be located has been successfully decoded and read, typically by illumination of an indicator lamp.
Or, by a sound being emitted from a sound generator,
I had to wait until I was informed. This method of searching around to read symbols is inefficient and time consuming, especially when a large number of symbols need to be read every hour of every day. Ta.

To enable a user to easily aim the laser diode light at a symbol, US Pat. No. 4,835,374 proposes a visually easily recognizable Even when using a laser beam that is not
An optical aiming device is proposed that allows the head to be visually positioned and aimed at each symbol. This light aiming device utilizes one or more light generating diodes that are separate and distinct from a visible light source, such as a laser light source. In a first mode of actuation of the trigger to visibly illuminate an area of the symbol, a manual trigger is used to activate the optical aiming device. This visible area is used for aiming. Immediately, in the second mode of activation of the trigger, the laser light source is activated and reading of the symbol begins.

The use of a separate optical aiming device allows the user to reliably aim the head at a symbol, primarily because the head is large and It has the disadvantage of being heavy and reducing energy efficiency. Using a separate light generating diode makes the head heavier, takes up more space within the head, and requires a separate power supply and control circuit.
There is a problem of power consumption. It is desirable to make the head as light, small, and efficient as possible.

[0008]

SUMMARY OF THE INVENTION It is a general object of the present invention to overcome the aforementioned drawbacks of conventional laser scanning devices. Another object of the invention is to eliminate light arrangements that must be aimed separately.

Yet another object of the invention is to enable a user to direct a laser beam emitted by a semiconductor laser diode to and across a symbol before and during scanning of the symbol. The goal is to make it easy to aim. Yet another object of the invention is to eliminate the need for trial-and-error methods when aiming a semiconductor laser diode beam at a symbol, especially for long working distances.

Yet another object of the invention is to increase the efficiency and reduce the time required to optically read symbols with a semiconductor laser diode beam. Yet another object of the invention is to precisely position a symbol relative to a semiconductor laser diode scanner before scanning and to precisely track the symbol with the semiconductor laser diode scanner during scanning.

Yet another object of the invention is to use the same light source for both aiming and reading purposes. Yet another object of the invention is to provide a multi-position manually depressable trigger for controlling aiming and reading. Yet another object of the invention is to provide a multi-position trigger for controlling the reading of symbols located at different distances from the head.

Yet another object of the present invention is to be very lightweight, streamlined, compact, handheld, completely portable, easy to operate, easy to operate without tiring arms or wrists, and to be easy to use with symbols, especially
A laser diode operating head and/or device such as is held completely by the user during optical reading of bar code symbols of the type known as Universal Product Code (UPC) as well as black and white symbols used in industrial applications. The goal is to provide the following.

[0013]

[Means for Solving the Problems] In order to achieve these objectives and other objectives as will become apparent below,
One feature of the invention, briefly, resides in an arrangement for use in aiming a hand-held scanning head in a laser device for reading the symbol at which the head is aimed. Several components are attached to the head in a conventional manner. For example, means are provided in the head for generating an incident light beam, preferably a laser beam, such as a semiconductor laser diode, or a gas laser or a non-laser source. optically altering the incident laser beam, i.e., toward and within a working distance of a reference plane located outside the head and in a plane approximately perpendicular to the direction of propagation of the incident laser beam; optical means, such as a positive lens, for forming and directing the incident laser beam along the first optical path towards the symbol;
Negative lenses, reflective mirrors or other optical elements are also provided within the head. For convenience, symbols located between the reference plane and the head will be referred to hereinafter as close-in symbols, while symbols located on the other side of the reference plane away from the head will be referred to as far-out symbols.

Laser light is reflected at the symbol, and at least a returned portion of the reflected laser light travels along a second optical path away from the symbol toward the head. A scanning means, for example a scanning motor having a reciprocally oscillating output shaft to which a reflective surface, such as a scanning mirror, is mounted, for scanning the symbol in one scan, preferably in multiple sweeps per second repeatedly across the symbol. , attached to the head. The return portion of the reflected laser light, in the case of a bar code symbol, has a light intensity that varies across the symbol during scanning due to the different light reflection properties of the bars and spaces that make up the symbol.

The head also includes sensor means for detecting the varying light intensity of the returned portion of the reflected laser light over the field of view and generating an electrical analog signal indicative of the detected varying light intensity. , for example, one or more photodiodes. Signal processing means are also attached to the head for processing the analog electrical signal, typically into a digital electrical signal that is decoded into data indicative of the symbol being scanned. The scanning means is operative to scan the incident laser beam itself across the symbol or the field of view of the sensor means, or both.

[0016] In some cases, but not always, the decoding/control electronics are provided at a location within the head or at a location remote from the head. The decoding/control electronics decodes the digitized signal into data as described above, determines that the symbol is successfully decoded, and decodes the symbol when the decoding is determined to be successful. operates to finish reading. The reading is performed by a manually operable triggering means provided in the head and operatively connected to the laser beam generating means, scanning means, sensor means, signal processing means and decoding/controlling means and operative to actuate each of these means. Initiated by actuation. The trigger means is actuated once for each symbol. In a preferred embodiment, actuation of the trigger means causes the decoding/control means to be actuated, and actuation of the decoding/control means causes the laser beam generation means, the scanning means, the sensor means and the signal processing means to be actuated. It will be done.

In conventional use, a head held in the user's hand is aimed at each symbol to be read, and once the symbol is located, the user activates the triggering means to begin reading. The decoding/control means alerts the user when a symbol is read so that he can direct his attention to the next symbol and the procedure is repeated. As mentioned above, when the incident or reflected laser beam is not easily visible, which may be caused by factors such as the wavelength of the laser beam, the brightness of the laser beam, the brightness of the surrounding light, the scanning speed, and other factors. There was a problem. This "invisibility" meant that the user could not see the laser beam and could not tell whether the laser beam was located on the symbol or whether the scanning laser beam was scanning the entire length of the symbol. It was not easy to know. To overcome this problem, prior art has proposed the use of multiple individual aiming optics.

However, according to the invention, rather than using multiple aiming optics, which would be associated with increased weight, increased dimensions and increased energy consumption, it is proposed to use the light source itself; Light from a light source assists the user in positioning and aiming the head at each symbol before reading the symbols. A light source (preferably a laser diode) is operatively coupled to the scanning means and the triggering means and is operable when energized by the triggering means to direct a light beam from the light source onto the reference plane and further onto each symbol. At least a portion (ie, a first region) of each symbol is visibly illuminated to position the symbol relative to the user. This makes it easier for the user to properly aim the head at each symbol to be read.

In one embodiment according to the invention, the apparatus directs a light beam at each symbol to illuminate a generally circular spot area on the symbol within the field of view, preferably near the center of the symbol. This spot area is preferably stationary (or stationary during symbol aiming) so that both symbols within the spot and symbols outside the spot can be seen and positioned by the user prior to its scanning. .

In another embodiment, the apparatus directs the light beam onto a scanning mirror that reciprocates to sweep the light beam across a portion of each symbol. In this case, the first region described above becomes a line region whose length is shorter than the length of the symbol. This dynamic targeting allows the in-region symbol to be more easily seen, positioned, and navigated compared to static targeting.

In yet another embodiment, said first region is a line region of length at least equal to (preferably greater than) the symbol length. This dynamic aiming is perfect for driving. Also, since scanning is performed over the entire symbol, the same light beam can be used for reading. Preferably, the device directs the light beam onto a scanning mirror that has a stationary state and at least one oscillating state. First, the light beam is directed onto each symbol by reflecting off a stationary or moving mirror, and is then directed to a spot or linear area within its field of view (preferably near the center of the symbol) before scanning the symbol. to position the symbol. The scanning mirror is then oscillated in another reciprocating vibration state to reflect the light beam onto the symbol and sweep it across the symbol, illuminating a line area extending along the entire symbol to read the symbol. I do.

[0022] In order to carry out such aiming and reading, the triggering means are preferably of multi-position type and are coupled directly or indirectly to the light source via decoding/controlling means similar to an oscillating scanning mirror. Preferably, in the first or off position of the trigger means, all components of the head are deenergized. In the second position or first operating mode, the light beam illuminates a scanning mirror located at a predetermined stationary position (e.g. central position) at a predetermined time, such that the light beam is to be read as it exits the head. It is directed to illuminate the central spot area of the symbol. In the third position or second operating mode, all other components of the head, including those responsive to reciprocating the scanning mirror, are energized to begin reading the symbol and move along the symbol. Start irradiating the line area.

[0023] In another embodiment, the scanning mirror is
In operation, it is oscillated back and forth in an arc of limited angle (1 degree to 5 degrees), illuminating a line area of limited length of the symbol. Then, in a second mode of operation, the scanning mirror is oscillated back and forth between an enlarged arc of a larger angle (e.g. 20 degrees to 40 degrees), creating a line of length extending across the entire symbol. Irradiate the area.

In yet another embodiment, the scanning mirror is oscillated back and forth between said enlarged arcs in both said modes of operation, such that either mode of operation serves both aiming and reading simultaneously. Can be used. This is particularly suitable for reading in-range and out-of-range symbols with the same head, and suitable for reading both high- and low-density symbols with the same head.

[0025] Possible novel features of the invention are set forth in the claims. The invention, however, both as to its construction and method of operation, together with additional objects and advantages, will be better understood from the following description of the embodiments, read in conjunction with the accompanying drawings.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A laser scanning head 10 is shown in FIGS. 1 to 6. This laser scanning head is lightweight (less than 1 pound) and
small-bodied, streamlined, small-front, hand-held, fully portable, easy to operate, free of arm and wrist fatigue, laser scanning for symbol reading, scanning and/or analysis; It is suitable for use in a mechanism and can further target multiple symbols, each symbol being in sequence, both before the start of reading and during reading. As used herein, the term "symbol" is intended to include all indications consisting of different parts having different light reflection properties depending on the wavelength of the light source used, ie, laser. This designation is based on the black and white industrial symbol (e.g. Co
de 39, Codabar, Interleav
ed 2 of 5, etc.) and common UPC barcode symbols. Alternatively, this display may be alphabetical and/or numerical. The term "symbol" is also intended to include an indicia located in a certain background area, i.e. an indicia in which the indicia, or at least a portion of the indicia, has light reflection properties that are different from those with respect to the background area. In this definition, "reading" symbols has great benefits in the fields of robotics and object recognition.

Referring to FIGS. 1-3, the head 10 includes a generally gun-shaped housing that includes a handle portion 12 that is generally rectangular in cross section and extends generally perpendicularly along the handle axis. , and a slender main body 14 extending substantially horizontally. Handle part 1
The cross-sectional shape and overall size of the head 2 are such that the user can easily hold and hold the head 10 in his/her hand. The body 14 and handle portion 12 are constructed from a lightweight, resilient, impact resistant, self-supporting material, such as a synthetic plastic material. The plastic housing is preferably injection molded, but can also be made by vacuum forming or blow molding. The housing constitutes a thin-walled hollow shell with an interior space. The volume of this interior space is less than 50 cubic inches, and in some cases 2
5 cubic inches or less. These values are not used as limitations, but are used as general values for the maximum size and volume of the head 10.

As shown in FIGS. 1 to 3, the main body 14 has a region projecting forward, and this region extends from the upper front wall 1.
6 and a lower front wall 18. The upper front wall 16 and the lower front wall 18 extend forwardly from each other and join at a nose portion 20 located at the most distal end of the head 10. Furthermore, the body 14 has a rear region, which region comprises the front wall 1
6, 18, and has a rear wall 22 spaced rearwardly from 6,18. The main body 14 also has a top wall 24, a bottom wall 26 below the top wall 24, and a pair of side walls 28, 30 that are parallel to each other and face each other between the top wall 24 and the bottom wall 26.

A manually activatable, preferably depressable, trigger 32 is mounted in the forward facing region of the head 10 so as to be pivotable about a pivot axis 34 . This forwardly facing region of the head 10 is where the handle portion 12 and the body 14 join, and is where the user's index finger would normally be located when the user grips the handle portion during use. The bottom wall 26 has a tubular neck portion 3
6, the neck portion 36 extending downwardly along the handle axis and terminating in a radially inwardly extending collar portion 38 of generally rectangular cross section. The neck portion 36 and collar portion 38 have forward facing slots through which the trigger 32 projects and pivots.

The handle portion 12 has a radially outwardly extending upper flange portion 40 of generally rectangular cross section which also has a forwardly facing slot through which the trigger can be inserted. 32 is protruding and pivots. Upper flange portion 40 is elastic and radially inwardly deformable. When this upper flange portion 40 is inserted into the neck portion 36,
Upper flange portion 40 engages collar portion 38 such that upper flange portion 40 deflects radially inwardly. As the upper flange portion 40 passes over the collar portion 38, its elasticity causes the upper flange portion 40 to return to its original undeformed state and engage the rear of the collar portion 38 as a snap-lock. To remove the handle portion 12 from the body 14, the upper portion of the handle portion 12 is deflected inwardly enough so that the upper flange portion 40 is again separated from the collar portion 38. In this way, the handle portion 12 can be pulled away from the neck portion 36. In this manner, handle portion 12 is removably snap-attached to body 14 and can be removed. If necessary, other handle parts can be attached to the main body, consisting of a set of interchangeable handle parts, each having a different part of the laser scanning mechanism, to adapt the head 10 to meet the various requirements of the user. It can also be done.

[0031] A plurality of components are attached to the head;
Some of which are actuated by triggers 32, either directly or indirectly through the control microprocessor, as described below. One of the components of the head is an actuatable light source (
4), for example, a semiconductor laser diode 42 operative to propagate and generate an incident laser beam when actuated by trigger 32. The light of this incident laser beam is not readily visible, or made invisible, to the user during operation, as described below. The diode may be continuous wave or continuous pulsed. The diode 42 requires a low voltage (e.g., a DC voltage of less than 12 V), which can be provided, for example, by a battery (DC) power source located within the head or by a rechargeable power source removably attached to the head. It may be supplied by a battery pack accessory or by the power core of a cable 46 that connects the head to an external power source (eg, a DC power source).

As shown most clearly in FIG. 4, laser diode 42 is mounted on a printed circuit board 48. As shown in FIG. An optical assembly is attached to the head and adjustably positioned on the diode 42 to optically modify and direct the incident laser beam through the first optical path toward the reference plane. This reference plane is located outside the head in front of the noise section and is approximately perpendicular to the longitudinal direction of propagation of the incident laser beam. The symbols to be read are on both sides of the reference plane adjacent to the reference plane,
It is located on one side or the other, ie anywhere within the depth of focus or field of view of the optically modified incident laser beam. This depth of focus or field of view is also known as the working distance of the symbol that can be read. The incident laser beam reflects off the symbol in many directions, and the portion of the reflected laser light that propagates away from the symbol and toward the rear of the head along a second optical path is known herein as the return portion. Of course, this part is not easily visible to the user.

As best shown in FIG. 4, the optical assembly includes an elongated, cylindrical optical tube 50 having a cylindrical bore 52 in the region of one end; The annular casing portion of the diode 42 is received within the bore 52 in a fitted manner to maintain the diode in a fixed position. Further, a lens barrel 54 is attached to an area at the opposite end of the optical barrel 50 so as to be movable in the longitudinal axis direction. The lens barrel 54 has an aperture stop 56
, a blocking wall portion 58 surrounding and serving as a boundary of the aperture stop 56, and a cylindrical side wall portion 60 serving as a boundary of the internal space.

The optical assembly further includes a focusing lens 62, such as a plano-convex lens, disposed in the first optical path and operative to focus the incident laser beam onto a reference plane. The aperture stop 56 is located on both sides of the lens 62.
Preferably, it may be arranged on the downstream side. A biasing means or tension coil spring 64 is disposed within the optical barrel and has one coil end bearing against the casing portion of the diode and another against the flat side of the lens 62. The spring 64 always presses the lens 62 against the blocking wall portion 58, thereby positioning the lens 62 to be fixed relative to the aperture stop 56. The lens 62 and the aperture stop 56 are connected to the lens barrel 54.
move in the longitudinal direction. Side wall part 6
0 is initially received in a screw-coupled or sliding-coupling relationship with the inner circumferential wall that bounds the optical barrel 50, and the desired longitudinal space between the lens 62 and the aperture stop 56 is obtained on one side and the diode 42 on the other. When installed, it is fixed to the inner circumferential wall, for example by gluing with adhesive or by tightening with fasteners. The longitudinal movement between the side wall portion 60 and the inner circumferential wall of the tube 50 provides an adjustable positioning means for the lens 62 and the aperture stop 56; the position of the lens and aperture stop relative to the diode cannot be fixed. This is a means for fixedly arranging the lens and the aperture stop at a predetermined distance from the diode.

Aperture stop 56 has a smaller cross-section than the cross-section of the incident laser beam at aperture stop 56 such that only a portion of the incident laser beam is directed downstream along the first optical path through aperture stop 56. I try not to reach the symbol. Blocking wall portion 58 blocks other portions of the incident laser beam from passing through aperture stop 56 . The cross section of the aperture stop is preferably circular for ease of manufacture, but may also be rectangular or elliptical. In that case, the longitudinal axis dimension of the rectangular or elliptical cross section is aligned with a large divergence angle of the incident laser beam to transmit more energy to the symbol.

According to the laws of refractive optics, the desired cross-section of the incident beam at the reference plane is determined by, among other things, the dimensions of the aperture stop, the wavelength of the incident beam, and the longitudinal distance between the laser 62 and the reference plane. . Therefore, assuming that the wavelength and longitudinal axis distance are the same, the cross-section of the beam at the reference plane can be easily controlled by controlling the cross-section dimensions of the aperture stop. Laser 6 aperture diaphragm
2, there is no need to consider lens tolerance when determining the beam cross-section at the reference plane.

The aperture stop 56 is located at the center of the laser beam, and the intensity of the light reaches the pn junction, that is, the diode 4.
It is made to be substantially uniform in a plane perpendicular to and parallel to the two emitters. Laser diode beams have non-radial systems
Therefore, it is understood that the light intensity in the plane perpendicular to the pn junction is brightest in the center of the beam and decreases radially outward. This is also true in planes parallel to the pn junction, but the strength decreases at a different rate. Therefore, by placing a small, preferably circular aperture in the center of a laser diode beam with a large elliptical cross-section, the elliptical beam cross-section at the aperture is transformed into a substantially circular one, p- The intensity of light in both planes perpendicular to and parallel to the n-junction is approximately constant. The aperture stop reduces the numerical aperture of the optical assembly to below 0.05, allowing a single lens 62 to focus the laser beam onto the reference surface.

In the preferred embodiment, the approximate distance between the emitter of laser diode 42 and aperture stop 56 is about 9
．． 7 to about 9.9 mm. The focal length of lens 62 is in the range of 9.5 mm to 9.7 mm. Aperture diaphragm 56
If it is circular, its diameter is approximately 1.2 mm. When the aperture stop 56 is rectangular, its size is approximately 1 m.
m x approximately 2 mm. The beam cross-sectional area is 3.0 mm x 9.3 mm just before the beam passes through the aperture stop 56 . These exemplary distances and sizes are such that the optical assembly deforms and focuses the laser diode beam onto a reference plane approximately 3 inches to approximately 4 inches from the nose portion 20 at a distance of approximately 6 mils. ) to form a 12 mil beam cross section. The working distance is
A proximity symbol, as previously defined, may be located between the portion approximately 1 inch away from the nose portion 20 and the portion leading to the reference plane, and an estrangement symbol, as previously defined, may be located between the reference plane and this reference plane. such that it can be located between approximately 20 inches from the surface.

The portion of the incident laser beam that passes through the aperture stop 56 is directed rearward by an optical assembly along an optical axis 102 within the head to a generally planar scanning mirror for reflection. This scanning mirror 66 reflects the incoming laser beam forward and along another optical axis 104.
It passes through a front laser light transmission window 68 mounted on the upper front wall 16 to reach the symbol. FIG. 7 best shows the markings 100 near the reference plane. A barcode symbol consists of a series of vertical bars spaced from each other along its length. Reference numeral 150 indicates a generally circular visible spot extending over the symbol. Laser spot 150 in FIG. 7 is shown in a static position or in an instantaneous dynamic position. When scanning mirror 66 is actuated by trigger 32, it may be positioned stationary or repeatedly oscillated laterally back and forth to longitudinally sweep the incident laser beam, as described below. cross some or all of the bars of the symbol.

Scanning mirror 66 is attached to scanning means, preferably a high speed scan motor 70 of the form shown and described in US Pat. No. 4,387,397. The entire contents of this patent are incorporated herein by reference. For the purposes of this application, we believe it is sufficient to point out that the scanning motor 70 has an output shaft 72 on which a support bracket 74 is fixedly mounted. Scanning mirror 66 is mounted on bracket 74. The motor 70 is driven to reciprocate and repeatedly oscillate the shaft 72 in alternating circumferential directions at a speed such that it oscillates multiple times per second over an arc of a desired size, typically less than 360 degrees. Ru. In a preferred embodiment, scan mirror 66 and shaft 72 are coupled and oscillated such that scan mirror 66 directs the incident laser diode beam at a reference plane from approximately 1 to 5 degrees in the first mode of actuation of the trigger. The second mode of operation of the trigger repeatedly sweeps over an angular range or arc length of 20 to 40 degrees at a rate of approximately 20 scans or 40 oscillations per second.

Referring again to FIG. The reflected laser light at the return position has different light intensities because different parts of the symbol being scanned, including the symbol 10, have different light reflection properties. The reflected portion of the laser beam is focused by a generally concave spherical focusing mirror 76, and is focused by the upper and lower boundary lines 108, 1 as shown in FIG.
10 and both side border lines 112 shown by FIG.
114 resulting in a wide conical flow of light within the conical focusing section delimited by . The condensing mirror 76 reflects the condensed light into the head along the optical axis 116 and passes it along the second optical axis to a photo sensor 80, for example.
leading to sensor means such as The focused cone of laser light directed toward the photosensor 80 is bounded by upper and lower boundaries 118, 120 (see FIG. 2) and side boundaries 122, 124 (see FIG. 2). It is being Photosensor 80 is preferably a photodiode that detects and detects the varying intensity of the focused laser light over a field of view extending along and preferably beyond a linear scanning area. generates an electrical analog signal indicative of the varying light intensity generated.

Referring again to FIG. Reference number 126 is
Symbol 100 where instantaneous laser spot 150 is reflected
This shows the instantaneous light convergence area that overlaps this. From another perspective, the photo sensor 80 is the laser spot 106
is "looking at" the focal region 126 when the light is incident on the symbol.
It turns out. A focusing mirror 76 is attached to a support bracket 74, and when the scanning mirror 70 is actuated by the trigger 32, the focusing mirror 76 is repeatedly oscillated back and forth in the lateral direction to capture symbols within the linear scanning area. The field of view of the photodiode is scanned across its length.

The head includes a pair of printed circuit boards 84,
85 is also attached, and various small substrates are attached on these substrates 84 and 85. For example, the substrate 84
Signal processing means comprising elements 81, 82 and 83 are operative to process the analog electrical signal produced by sensor 80 and generate a digitized video signal. Data representative of the symbols is obtained from the video signal. Signal processing means suitable for this purpose are described in US Pat. No. 4,251,798. Elements 87 and 89 on the substrate 86 constitute a drive circuit for the scanning motor 70. A suitable motor drive circuit for this purpose is described in US Pat. No. 4,387,297. Element 91 on substrate 86 constitutes a control switch. This operation is described below. Diode 42 and sensor 80 on substrate 48
is attached, and element 93 on substrate 48 is a voltage converter that converts the input voltage to laser diode 4.
2 to a suitable voltage for energizing. The entire contents of U.S. Pat. Nos. 4,251,798 and 4,387,297 are incorporated herein by reference;
and forms part of this application.

The digitized video signal is sent to the main body 14.
and a mating plug 90 in the handle portion 12. Plug 90 automatically mates electro-mechanically with socket 88 when the handle is attached to the body. A pair of circuit boards 9 are installed inside the handle.
There are 2,94 (see Figure 1). Various elements are mounted on this substrate. For example, elements 95, 9
The decoding/control means comprising 7 and 7 is operative to decode the digitized video signal into a digitized decoded signal and from this signal to represent the symbol by an algorithm contained in the software control program. Desired data can be obtained. The decoding/control means includes a PROM that holds a control program, a RAM that temporarily holds data, and a control microprocessor that controls the PROM and RAM. The decoding/control means determines when a symbol has been successfully decoded and terminates the reading of the symbol when it determines that the symbol has been read successfully. The reading is started by pressing the trigger 32. The decoding/control means also includes control circuitry. This control circuit controls the operation of the operable elements in the head when initiated by a trigger and automatically terminates the reading, for example by sending a control signal to an indicator lamp 96 and activating that lamp. Inform the user of what has happened.

The decoded signal, in one embodiment, is provided to a remote host computer 128 along signal conductors within cable 46. This host computer 1
28 essentially acts as a large database, storing the decoded signals and, in some cases, providing information related to the decoded signals. For example, the host computer
Provide retail price information corresponding to that specified by the decoded symbol.

In another embodiment, a partial data storage means, such as element 95, is attached to the handle and stores a number of decoded signals to be read. This stored decoded signal is transferred to a remote host computer. By providing partial data storage means, the use of cable 46 can be eliminated during symbol reading - a highly desirable feature if the head is to be made as freely manoeuvrable as possible.

Voltage signals are transmitted along power conductors in cable 46 to power the laser diode 42 and the various elements within the head that require power. A converter such as element 93 is then used to convert the input voltage signal to the required voltage value. According to the invention, by using a discrete illumination array, the laser diode 42 itself is used for that purpose. As shown in FIG.
is in an off state, and at least some, if not all, of the operable elements in the head are rendered inoperable. A pair of electrical switches 158, 160 (see FIG. 5) are mounted on the underside of the board 84. switch 158
, 160 each have a spring biased armature or button 162, 164 which, in the off state, extends from the switch and is located in the opposite end region of the lever 166. ing. The lever 166 is then connected to a rearward extension 170 of the trigger 32.
The center point 168 rotates at a center offset position.

As shown in FIG. 5, when the trigger 32 is first pressed to the initial starting range, the lever 166 depresses only the button 162 and the pressed switch 158 establishes the initial operating state. In this initial operating state,
Diode 42 is activated and its light beam is directed backwards to scanning mirror 66 and reflected therefrom in a forward direction. Alternatively, diode 42 is already on and the trigger is actuated to cause the light beam to travel toward the scanning mirror. In the first operating state, the trigger places the scanning mirror 66 in a fixed position. This fixed scanning mirror 66 directs a light beam onto the symbol and visibly illuminates the spot area 150 in the field of view prior to scanning to assist the user in locating the symbol prior to reading it. The scanning mirror 66 is fixedly positioned by a scanning motor 70.
This is advantageously done by energizing the DC winding of the output shaft, so that the output shaft and the scanning mirror 66 attached thereto are rotated to an angularly central reference position. DC voltage is switched to the motor windings by control switch 91. When the scan motor is stationary, power to the laser diode is reduced to conserve energy.

Rather than maintaining the scan mirror in a steady state, the trigger controls the control circuits 87, 89 for the scan motor 70.
and/or the diode 42 can be operated to oscillate the scanning mirror 66 over a portion of the arc, e.g. on the order of 1° to 5°, to create a portion of the linear region 152 on the symbol (see FIG. 8). ) is visibly illuminated. This linear area is smaller than the length of the symbol. To limit operation, the scan motor windings are electrically connected to a predetermined magnitude of AC drive current by a switch.

Alternatively, the scanning mirror 66 may vibrate over an extended arc, for example on the order of 20° to 40°,
Illuminate the extended portion of the linear region (see 8) on the symbol. This linear area is at least equal to the length of the symbol. To limit operation, the scan motor windings are electrically connected by a control switch 91 to an AC drive current of magnitude greater than the predetermined magnitude.

When the trigger 32 is depressed to the second range as shown in FIG.
2 and button 164, a second operating condition is established. In this second operating state, the trigger 32
is a control circuit for the scan motor 70 that reciprocates all the remaining drivable elements in the head, such as the laser diode 42, the scan mirror 66, and the photodiode 80.
, the signal processing circuit is driven in the same way as the circuits in the other heads, and symbol reading begins. The reciprocating motion of the scanning mirror 66 dynamically moves the light beam along the entire symbol, discernably illuminating the same line area 156 extending along the field of view. Therefore, during scanning, the user assists in tracking the symbol while it is being read. The trace of this symbol is
Nearby symbols can be recognized with good accuracy, but far away symbols can be recognized with poor accuracy.

If the first and second regions are perceptible linear scans and extend along the entire symbol, they may have different densities or be relative to the head. It is possible to use the same head to read differently positioned symbols. Sequential actuation of the elements in the head described above can also be achieved using a single two-pole switch with integrated continuous contacts.

As shown in FIG. 1, a number of different elements within the head are mounted for shock mitigation by a front shock isolation member 172 and a rear shock isolation member 174. On this front shock isolating member 172, a table 48 and all the elements on this table 48 are supported, and on the rear shock isolating member 174, a support plate 176 to which a scanning motor 70 is attached is supported. There is. Light baffle 178 further partitions the interior of the body and prevents stray ambient light from reaching photosensitive device 80 .

The laser scanning head shown in FIG. 2 is of the retro-reflective type and the incident laser light is scanned out of the field of view of the sensor means as well. Various variations are included in the invention, for example, while the field of view is not scanned and the returning laser light is collected through another window on the head, the incident laser light outside the field is You can also move along the symbol. Also, the incident laser light outside the range may be directed toward the symbol but not move along the symbol while the field of view is being scanned.

Various housing shapes may be employed in place of those shown, depending on considerations such as aesthetics, environment, size, selection and placement of mechanical and electrical components, and the required internal and external shock resistance of the housing. can be done. In accordance with the present invention, the laser scanning head need not be of the hand-held type, but may be a stand-alone workstation of the desktop type. For this workstation, the symbol passes through the workstation and preferably passes under an overhead window onto which the incident out-of-range laser light is directed. Even though the workstation itself is acceptable, at least during scanning of the symbol, the symbol is movable relative to the workstation and registers with incident laser light that is out of range.

[0056] According to the present invention, the laser scanning head unit can print high density, medium density and low density bar code symbols, for example
It can be read within working distance ranges of ''~6'', 1''~12'', and 1''~20'', respectively. As defined herein, high-density, medium-density, and low-density barcode symbols have bars and/or spaces with minimum widths of 7.5 mils, 15-20 mils, and 30 mils, respectively. ~
It is on the order of 40 mils. In a preferred embodiment, the location of the reference plane for a symbol of known density is optimized for the maximum working distance of that symbol.

Furthermore, in the present invention, the linear area on the symbol, which is the target light spot, can be made to flicker, for example, in order to make the illumination area easier to see, or the average power consumed by the laser diode can be reduced. desirable. Such a flickering region can be created by electrical and/or mechanical means. Although in the embodiments of the invention described above a multi-position trigger for a portable laser diode scan head is shown, the invention is not limited thereto and various modifications may be applied.

[Brief explanation of the drawing]

1 is a front view of a portable scanning head according to the invention; FIG.

FIG. 2 is an enlarged cross-sectional view taken along line 2-2 in FIG. 1;

FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2;

4 is a cross-sectional view taken along line 4-4 of FIG. 2. FIG.

FIG. 5 is an enlarged detail view of the trigger assembly in a first operating configuration;

FIG. 6 is an enlarged detail view of the trigger assembly in a second mode of operation;

FIG. 7 is an enlarged view of one embodiment showing the symbol and a portion of the symbol being illuminated during aiming.

FIG. 8 is an enlarged view of another embodiment showing the symbol and a portion of the symbol being illuminated during aiming.

[Explanation of symbols]

10 Laser scanning head 12 Handle part 14 Main body 20 Nose part 32 Trigger 36 Neck part 38 Color part 40 Upper flange part

Claims (20)

[Claims] 1. An optical scanning device for optically scanning a symbol with portions having different light reflectivity, comprising: (a
) a housing having an exit port; (b) a light source disposed within the housing and generating a light beam; (c)
disposed within the housing, the light beam is emitted from the exit opening to illuminate a first region on the symbol in a first mode of operation, and illuminates a second region on the symbol in a second mode of operation. (d) actuating means for actuating said control means in any of said operating modes; target scanning device. 2. The optical scanning device of claim 1, wherein the housing has a handle for hand-held operation, and the actuating means is a manually operable actuator provided on the housing. target scanning device. 3. An optical scanning device according to claim 2, wherein said actuator includes a multi-position trigger operatively connected to said control means to select said actuation mode. 4. The optical scanning device according to claim 3, wherein the first region is a static aiming region;
The optical scanning device, wherein the second area is a linear dynamic reading area that spans the entirety of the symbol. 5. The optical scanning device according to claim 3, wherein the first region is a linear dynamic reading region extending over a portion of the symbol, and the second region is a linear dynamic reading region extending over a portion of the symbol. An optical scanning device that is a linear dynamic reading field that exists throughout. 6. The optical scanning device of claim 3, wherein the two regions are linear dynamic reading regions located at different distances from the exit port of the housing. 7. The optical scanning device according to claim 1, wherein the light source is a laser that generates a laser beam, and the control means controls the first and second points on the symbol under respective operating modes. An optical scanning device adapted to direct the laser beam to illuminate a second area. 8. An optical scanning device according to claim 1, wherein said control means comprises a movable scanning element operative to swing said light beam along said symbol under one of said operating modes. An optical scanning device comprising scanning means. 9. The optical scanning device according to claim 8, wherein the scanning means is a reflecting mirror, and the reflecting mirror comprises:
An optical scanning device mounted for repeated reciprocating motion in alternately opposite directions along an arc relative to an axis. 10. An optical scanning device as claimed in claim 9, wherein the actuation means maintains the scanning element stationary in the first mode of operation and only by a predetermined angle in the second mode of operation. An optical scanning device adapted to repeatedly reciprocate the scanning element along the arc. 11. The optical scanning device according to claim 9, wherein the actuating means repeatedly reciprocates the scanning element along an arc of a limited angular range in the first operating mode; In the second operating mode, the scanning element is repeatedly reciprocated along an arc within a predetermined angular range that is larger than the limited angular range;
Optical scanning device. 12. The optical scanning device according to claim 9, wherein the actuating means repeatedly reciprocates the scanning element along an arc over a predetermined angular range in both the first and second actuation modes. Optical scanning device adapted for movement. 13. Scanning means for generating a laser beam directed at an object, a first selection position allowing a user to aim and direct the laser beam at a desired location; a control means for generating a first scanning pattern and, at a second selected position, generating a second scanning pattern for scanning the entirety of the symbol to be read; and receiving reflected light from the symbol to be represented by said symbol. A reading device for bar code symbols, etc., comprising detection means for generating an electrical signal. 14. The reading device of claim 13, wherein the housing has a handle for hand-held operation, the scanning means and the detection means are located within the housing, and the control means is mounted on the housing. A reading device, which is a manually operable actuator installed in the. 15. A reading device according to claim 14, wherein said actuator includes a multi-position trigger connected to said control means for selecting said selected position. 16. A reading device as claimed in claim 13, wherein the scanning means comprises a movable scanning element for deflecting the laser beam along the symbol at one of the selected positions, and the control means comprises a , repeatedly reciprocating the scanning element along an arc over a limited angular range at the first selected position and along an arc over a predetermined angular range greater than the limited angular range at the second selected position; a reading device, wherein said scanning element is repeatedly reciprocated by means of said scanning element; 17. A first scanning pattern is formed by the laser beam to produce a laser beam directed at an object and to enable a user to aim and orient the beam to a desired location. , selecting a second selected position to generate a second scanning pattern across the symbol to be read, receiving light reflected by the symbol to receive an electrical signal corresponding to data represented by the symbol; A method of reading barcode symbols, etc., consisting of forming a . 18. The reading method according to claim 17, wherein the means for generating a laser beam is attached to a housing having a handle for hand-held operation, the scanning means and the detection means are attached to the housing, and the means for generating a laser beam is attached to the housing, and the means for generating a laser beam is attached to the housing and has a handle for hand-held operation. attaching an actuator to the housing;
A reading method in which the selection position is selected. 19. The reading method of claim 18, wherein the actuator has a multi-position trigger for selecting the scanning pattern. 20. The reading method of claim 17, wherein the step of creating a laser beam includes mounting a movable scanning element on a housing for swinging the beam along a symbol and being confined at a first selected position. a reading method comprising repeatedly reciprocating the scanning element along an arc over a predetermined angular range, and repeatedly reciprocating the scanning element at a second selected position over a predetermined angular range greater than the limited angular range. .