JPH04506880A - Vibrationable holographic optical element for bar code scanning - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] Vibrationable hologram optical element technology for bar code scanning The present invention relates to holographic optical elements, and more particularly to bar code scanning readers. A holographic optical element that can vibrate for use with a capture device. related.

Background technology Bar code readers typically use a beam of light to scan across a bar code. This bar code consists of alternating strips with different reflectances (“ bar”). The scanner is triggered by this bar code. It receives and analyzes the fluctuations in the reflected light. In the prior art, bar code markings It is known to read bar codes with a hand-held wand that makes contact with a printed surface. It is being However, the need to make contact with this surface is often unnecessary. feces, and this thin rod does not move across the bar code at a uniform speed; The read result becomes impossible to analyze.

An alternative to a handheld wand is a scanning reader, which – does not require physical contact with the cord. Scanning readers generally use a beam of light. generated and this beam is repeatedly scanned across an area. If this ray is a bar code (or any other code), this bar code will The scattered modulated light returns to detection circuitry within the scanning reader for analysis.

Relative time required for a ray to scan the width of alternating regions of different reflectance Measure the width of these areas based on. The relative width of the bar code elements is This allows the reader to read bar codes with various sizes unless lost. becomes possible to use. Therefore, it facilitates the task of analyzing bar codes. In order to scan a bar code at a substantially constant speed, Although not necessarily necessary, this is preferable.

To ensure that the ray is scanned at a substantially uniform speed, this ray should be reflected from a mirror in the scanner that moves repeatedly at a uniform speed. This mi The motor is typically driven by a small electric motor controlled by an electronic control circuit. . This mirror typically rotates at a constant speed or between two extreme angular positions. vibrates at the end of a shaft attached to a motor that can move the Either. An example of rotating an optical element is U.S. Patent No. 4.025.7. No. 61, No. 4,097,729, No. 4,450.350, No. 4,575.625 , and 4,692.603. Vibrate the optical elements of the mirror Examples include U.S. Pat. No. 08,804.

When adapting to a handheld type, a vibrating mirror is generally preferred; Can they be made lighter and more compact than rotating optical elements? It is et al. This mirror typically includes a condenser mirror, which is Receives and focuses the light scattered from the symbol of the bar code being scanned. .

In order to reduce power consumption, it is important to make the vibrating mirror as light as possible. be.

Disclosure of invention The object of the present invention is to create a hologram that scans a oscillating light beam against the symbol of a bar code. An object of the present invention is to provide a system optical element.

Another object of the invention is to provide a monolithic optical element having a holographic optical element. in which the holographic optical element is used to bar the oscillating beam of light. ・Transmits the light received from this bar code symbol to this integrated bar code symbol. Focus on a fixed point for the optical elements of the structure.

Another object of the invention is to provide a lightweight light beam scanning device for scanning a beam of light against the symbology of a bar code. The objective is to provide optical elements.

Still another object of the present invention is to use a low electrical current for scanning the light beam into the symbol of the bar code. The objective is to provide a lightweight optical element that requires only force.

For these and other purposes, light is transmitted across the symbology of a bar code by vibration methods. A monolithic light beam that transmits the bar code and focuses the light scattered from the symbol of this bar code. A monolithic optical element can be achieved using holographic elements. It is composed of multiple elements.

Additionally, these and other purposes may include reading the symbology of a bar code and This is achieved by a vibrating scanner that focuses the light received from the symbol of the code. Can be done. This scanner is a means of generating a coherent beam of light, Means for directing said received beam of light to the sign of said bar code; hologram element, and the above hologram element is identified by the sign of the above bar code. Using the vibration method, the hologram is It is constituted by means for moving the beam element.

Furthermore, these and other purposes require distinct areas of contrast in reflectance to be This can be achieved by a scanner that reads the bar code symbol.

This scanner uses a means of generating a coherent beam of light, a means of generating a coherent beam of light, ・Means for directing the received rays of light to the sign of the code, a holographic element for focusing the received rays child, the above hologram element is scattered by the symbol of the above bar code The above hologram element is moved using the vibration method so that it faces in the direction of receiving the light beam. means located at a substantially fixed point and reflecting said received rays; by means of a conversion means which converts it into an electrical signal representing the above-mentioned distinct areas with contrast. It is composed of

Brief description of the drawing FIG. 1 is a perspective view of a scanning laser bar code reader.

FIG. 2 is an end view of the top end of the scanning laser bar code reader shown in FIG. It is.

Figure 3 is an exploded oblique view of the optical system of the scanning laser bar code reader shown in Figure 1. This is a perspective view.

Figure 4 is a top view of the optical system of the scanning laser bar code reader shown in Figure 1. It is.

Figure 5 shows the motor drive power supply for the scanning laser bar code reader shown in Figure 1. It is a schematic diagram of a child circuit.

Figure 6A shows the vibration used in the scanning laser bar code reader shown in Figure 1. 1 is a top view of a possible holographic optical element; FIG.

FIG. 6B is a front view of the vibratable holographic optical element shown in FIG. 6A.

FIG. 6C is a side view of the vibratable holographic optical element shown in FIG. 6A.

FIGS. 1 and 2 illustrate how the holographic optical elements of the present invention are intended to cooperate. An example of a laser scanner of this type is shown. Figures 1 and 2 are handheld. The holographic optical element of the present invention is shown as an integrated laser scanner of the formula , as well as others including counter built-in scanners and tabletop scanners. It can also be used in other optical scanning systems. Furthermore, such optical Scanning systems are not necessarily limited to scanning bar codes. Figure 2 is 2 is an end view of the top end of the laser scanner shown in FIG. 1; FIG. Laser love The scanner IO has an electronic circuit and optical components, which are built into the case 10. Ru. This laser scanner 10 has a keyboard 14 and a liquid crystal display (CD) 16. , and these allow the bar/bar read by the laser scanner 10 to be read by the laser scanner 10. In addition to displaying the code, the laser scanner 10's built-in microprobe Program a processor (not shown).

When a pair of opposing triggers 18 (only one is shown in FIG. 4) is actuated, the Laser scanner 10 is activated to scan the laser beam, as described subsequently. Light 22 is generated. As shown in FIG. It passes through a land 2o provided at the upper end of. Scanning takes place in plane 24 (second (shown in figure). A beam from scanning beam 22 is emitted in front of laser scanner 10. Ru. If this reaches a surface, some of the energy hitting this surface will be scattered. and return to window 22. If there is a bar code on the scattering surface hit by the scanning laser beam, If the symbol of the bar code is included, the reflected light will reflect the reflection contained in the symbol of this bar code. modulated by the emissivity pattern. The light received by the laser scanner 10 is , if this is scattered from the bar food code, then the bar code by circuitry according to techniques conventional to those skilled in the art of reader design. amplified and processed.

FIG. 3 is an exploded perspective view of the optical system of the laser scanner 10 shown in FIG.

Figure 4 shows the top view of the optical system of the scanning laser bar code reader shown in Figure 1. It is a diagram. The laser scanner 10 shown in Figures 3 and 4 uses visible light. to scan the symbol on the bar code.

The optical system of the internal components of laser scanner 10 is composed of two parts. Preferably, it is built into the support frame 30. This support frame 30 is a part 30a and 30b, which are fastened to each other by snaps to hold optical components and forming an integral support member for and associated parts. This support frame The parts within 30 can be divided into two categories. On the other hand, at the beginning of the range, scanning light n was It includes the parts that generate and transmit. In the other field, the result of transmitting the scanning light 22 is shown. It includes parts that receive and process all the returning light.

These parts of the 1st category include a laser diode 32, a rotating mirror 34, and a hologram. A gram element 36 and a motor 38 are included. Laser scanner 10 other An electronic circuit built into the part connects the wire 40 to the laser diode 32. Electricity is supplied through the A holder 42 moves with the laser diode 32 and The holder 42 includes a fixed assembly for shaping the scanning beam 22 into the desired shape. Necessary lenses and other optical elements are included and maintained. For example, running Scanning light 22 is generated from a laser beam generated by laser diode 32. This scanning light 22 can be transmitted to a specific source external to the laser scanner 10. This beam is directed from one laser diode 32 to help focus it in the plane of and/or transform the shape of this ray to obtain a desired cross section. Go through the Aperture stop to get it.

After the scanning beam 22 passes through the optical element held in the holder 42, it is transferred to a rotating mirror. - 34 through a hole 44 to reach the hologram element 36. The hologram element 36 is attached to the motor 38 by a shaft 46, thereby causing the hologram element 3 to 6 vibrates along with this motor 38 about an axis aligned with the shaft 46. do. Surface 24 (see FIG. 2) is aligned with shaft 46 relative to this axis. Vertical. The scanning light 22 is diffracted from the hologram element 36 and is reflected by a window in the plane 24. The direction is determined by the position of this hologram element 36 through the door 20.

Scattered from objects such as bar codes external to the laser scanner All the light received by the window 20 is transmitted through the window 20. win The card 20 connects the inside of the laser scanner 10 to the outside of this laser scanner 10. protection from contaminants. The reflected light is transferred to a rotating mirror by the hologram element 36. 34, and after this light passes through the filter 62, this rotating mirror 34 directs this light to photodiode 60. This hologram element 36 has a small The spider is at least the same size as the window 20, and as a result, basically the effect of the received light is All of the energy is directed to photodiode 60. This allows the photodiode to The strength of the signal generated by the ode 60 is at its maximum, which causes the foot diodes to The performance of the electronic circuitry that processes the signals generated by the code 60 is improved.

Figure 5 shows the motor drive electronics of the scanning laser bar code reader shown in Figure 1. FIG. 2 is a schematic diagram of a circuit. The motor 38 generates steps with a width of 18 degrees, for example. It is a stepping motor with the ability to This motor has two windings 80A and 8 Cultivate 0B. Each of these volumes #180A and 80B grows a tap in the center and this This divides the winding into two legs. The center of each of these windings The supply voltage is substantially fixed, such as the supply voltage for the electronics of the laser scanner lO. The voltage is maintained at the first voltage. Typically this supply voltage is 5V. These two Each leg of the two windings 80A and 80B is separately energized. To do this, use this The ends of each of these legs have one of the transistors 821,...,824. Each can be grounded via a circuit. (or if appropriate (can be held at a different voltage). For example, an appropriate signal is applied to the point and the gate of transistor 821 allows current to pass through the upper leg of winding 80A. Ru. This causes the motor 38 to rotate slightly. If the signals are in the correct order at points A, λ , B and the motor 38 and the resulting vibrating hologram. The vibration element 36 can be vibrated. As a result, the ray 22 is now in the window. 22. This also allows the light ray 22 to be received from the direction in which it was transmitted. The emitted light is focused by a photodiode 60. If the signal is at points A, W, B, If added correctly to Continuously move along the route within. If you wish, ray 2 between these extremes 2 can be given a substantially constant angular velocity.

The signals applied to points A, W, B, and π may be generated by electronic logic device 84. You can do something like that. This device 84 also generates a pulse train or other suitable signal as an oscillator. 86 and receives a motor motion detection signal on line 88.

Logic device 84 can be fabricated as a gate array. user or both Logic unit 84 in response to a signal generated when the birds operate -18 simultaneously. generates a large number of signals. Among the signals generated by this logic device 84 are points A and X. , B, and ■ signals necessary to drive the motor 38, "scan start" signal and ``There is an operation OKJ signal.'' The ``Start scanning'' signal is inside the laser scanner 10. The signal generated by the photodiode 60 is added to other electronic circuits of the Signal processing to read bar code symbols (if any) such as Start. If the motor 38 is not operating due to the operation OK J signal, Other circuitry connected to logic device 84 within laser scanner 10, if indicated. The operation of the Kaluzer diode 32 is stopped.

FIGS. 6A, 6B, and 6C show the top of the holographic optical element 36, respectively. A front view, a front view and a side view are shown. The holographic optical element 36 is vibrated to cause the first It can be used in the scanning laser bar code reader shown in the figure. this The vibration can be carried out by means of a shaft 46, which is connected to the holding hand. It is attached to the holographic optical element 36 via a step (not shown). This protection The holding means holds the holographic optical element 36 (which is substantially flat) on the shaft 4. This is a fixture for holding in a fixed position with respect to 6. This holographic optics Element 36 is attached to shaft 46 by gluing or other methods. It can be fixed permanently. Therefore, the shaft 46 is prevented from vibrating along with the motor 38. Then, this holographic optical element 36 also vibrates (see FIG. 3). What is this vibration? It can occur about an axis that is fixed relative to the optical element 36 of the structure.

If desired, holographic optical element 36 can be fabricated using conventional processes well known to those skilled in the art. Therefore, it is possible to manufacture it on a lightweight plastic substrate. In one example , the holographic optical element 36 has a surface 120 with two optical elements, elements 122 and 12. It can be divided into 4 parts. In FIG. 6, optical element 122 has optical element 124 removed. Although shown as surrounding, this configuration is not required for the invention.

At least one of optical elements 122 and 124 must be a holographic optical element. do not have. Both can be holographic if desired. If one of the optical elements For example, if element 124 is not holographic, it is a mirror. like this A mirror is useful for transmitting the light beam 22 to the symbol of the bar code. This structure In the design, another optical element (e.g., element 122) that is holographic may be used to - Collects the light reflected from the symbol of the code and directs this light to the holographic optical element 36 can be used to focus on a substantially fixed point. The optical element 122 is a well-known By appropriately developing the holographic principle of It is possible to manufacture.

If both optical elements 122 and 124 are desired to be holographic optical elements, For example, the optical element that transmits light to the bar code symbol can also be used as a mirror. In order to perform this function, it is possible to make it holographically.

In other embodiments, the two optical elements 122 and 124 are superimposed on each other. It can be efficiently produced using holography. This means that the holographic light By sequentially exposing the medium on which the optical element 36 is made to two separate sets of light beams. can be achieved. Outgoing holographic light by one set of rays The receiving holographic optical element is formed by the other set of light, and the receiving holographic optical element is formed. will be accomplished. The other set of rays is matched with the incoming and outgoing beams to form the scanning beam. Ru. The other set of rays is matched with the incoming and outgoing rays formed by the focusing mirror. ing. In either case, a holographic optical element is generated by each set of rays. is formed by an interference pattern.

The holographic optical element 36 is an additional feature for oscillating mirror assemblies known in the art. It can exhibit advantageous characteristics. Optical efficiency lies in wavelength selectivity, so holographic The graph optical element 36 also functions as a filter and can be used by the scanner. All light rays except those having the wavelength of the ray can be filtered. This is it Therefore, there is no need to use the separation filter 62 (see FIG. 3).

Having provided the above detailed description of specific examples, those skilled in the art will appreciate that the invention disclosed herein It is understood that many other circuits can be used to achieve the purpose of the device. Understand. Therefore, without departing from the spirit and scope of the invention, the embodiments described above may be modified. It is understood that various modifications may be made. Accordingly, the spirit and scope of the invention is limited only by the scope of the claims below.

abstract The present invention uses a vibrating hologram for scanning a light beam across a bar code symbol. It is an optical element. The hologram element (36) holds the hologram element in a vibrating manner. Can be mounted on the frame. The hologram element moves outward toward the bar code symbol. transmit the light to the side or collect the light reflected from the bar code symbol.

Or both. The hologram element can be a single hologram or two separate holograms. It consists of a gram or two superimposed holograms. Also horog The RAM element can also operate as a light receiving filter.

Claims (34)

[Claims] 1. Transmits a beam of light across the symbol of the bar code in an oscillatory manner, In a monolithic optical element that focuses light rays reflected from a code, the monolithic The optical elements of the structure are: An optical element having an integral structure, characterized in that it is constituted by a hologram element. 2. further comprising holder means attached to said holographic element. An optical element of monolithic structure according to claim 1, characterized in that: 3. The light beam reflected by the above optical element scans across an area. further comprising means for moving said holder means by a vibration method so as to An optical element of monolithic structure according to claim 2, characterized in that: 4. The holographic element above focuses the light rays reflected from the symbol of the bar code above. 2. An optical element of monolithic structure according to claim 1, characterized in that the optical element has a monolithic structure. 5. Said holographic means directs said received light beam into said monolithic optical system. Claim 1, characterized in that the element is focused at a substantially fixed point. 4. The monolithic optical element according to item 4. 6. further comprising holder means attached to said holographic element. 5. An optical element of monolithic structure according to claim 4. 7. The light beam reflected by the above optical element scans across an area. further comprising means for moving said holder means by a vibration method so as to 7. An optical element of monolithic structure according to claim 6, characterized in that: 8. It may further be constituted by a mirror that directs the light beam to the symbol of the above bar code. An optical element of integral structure according to claim 4, characterized in that: 9. further comprising holder means attached to said holographic element. 9. A monolithically constructed optical element according to claim 8. 10. A beam of light reflected by the mirror means described above is scanned across an area. further constructed by means of moving said holder means by a vibratory method so as to do so. 10. An optical element of monolithic structure according to claim 9, characterized in that the optical element is made of a single piece. 11. The above hologram element converts the received light beam into an optical system of the above monolithic structure. Claims characterized in that focusing is performed at a substantially fixed point relative to the target element. 11. An optical element having an ikkyu structure according to item 10. 12. The movement of said holder means is fixed relative to said monolithic optical element. of the integral structure according to claim 11, characterized in that the optical element. 13. Enhanced by a hologram optical element that directs the light beam to the symbol of the bar code above. 5. An optical element of integral structure according to claim 4, characterized in that it is constructed as follows. 14. further comprising holder means attached to said hologram element; 14. A monolithically constructed optical element according to claim 13. 15. A beam of light reflected by the mirror means described above is scanned across an area. further constructed by means of moving said holder means by a vibratory method so as to do so. 15. An optical element of monolithic structure according to claim 14, characterized in that the optical element is made of a single piece. 16. The above hologram element converts the received light beam into an optical system of the above monolithic structure. Claims characterized in that focusing is performed at a substantially fixed point relative to the target element. 16. A monolithic optical element according to claim 15. 17. The movement of said holder means is fixed relative to said monolithic optical element. of the integral structure according to claim 16, characterized in that the optical element. 18. means for filtering the wavelength of said light beam reflected from said symbol of said bar code; The monolithic light according to claim 4, further comprising: scientific element. 19. The holographic means described above focuses the received beam of light to a single point. A monolithically constructed optical element according to claim 1. 20. The above holographic element directs the light beam to the symbol of the above bar code. A monolithically constructed optical element according to claim 1. 21. further comprising holder means attached to said hologram element; 21. A monolithically constructed optical element according to claim 20. 22. The light beam reflected by the above optical element scans across one receiver. further comprising means for moving said holder means by a vibration method so as to 22. An optical element of monolithic structure according to claim 21, characterized in that: 23. The above hologram element converts the received light beam into an optical system of the above monolithic structure. Claims characterized in that focusing is performed at a substantially fixed point relative to the target element. 23. A monolithic optical element according to clause 22. 24. The movement of said holder means is fixed relative to said monolithic optical element. of the integral structure according to claim 23, characterized in that the optical element. 25. Read bar code symbol and receive from above bar code symbol In the vibration scanner that focuses the light beam, the vibration scanner mentioned above is: means for generating a ray of light; Means for directing said beam of light to the symbol of said bar code; a hologram element to focus; and said hologram element is said bar code; in the vibrational manner so that it faces in the direction that receives the above rays reflected by the sign of means for moving the hologram element; A vibration scanner characterized by comprising: 26. The holographic means described above directs the received light beam to an integrally constructed optical element. Claim 25, characterized in that the focus is focused on a point substantially fixed to the An optical element of monolithic structure as described in Section 1. 27. The above means for moving the above hologram element includes moving the above hologram element. Claim 1 characterized in that it is constituted by holder means attached to 26. The monolithic optical element according to item 25. 28. The above hologram element converts the received light beam into an optical system of the above monolithic structure. Claims characterized in that focusing is performed at a substantially fixed point relative to the target element. 28. A monolithic optical element according to clause 27. 29. The movement of said holder means is fixed relative to said monolithic optical element. of the integral structure according to claim 27, characterized in that the optical element. 30. Read bar code symbols that have distinct areas of contrast in reflectance. In scanners that take Dan; Means for directing said rays to the symbol of said bar code; combining said rays received; Focusing hologram element; The above hologram element is Using the vibration method, move the hologram so that it faces in the direction that receives the reflected rays. means for moving the ram element; and Contrast to the reflectance of the received light rays located above a substantially fixed point converting means for converting into electrical signals representative of the above-mentioned distinct regions; A scanner characterized by: 31. The above-mentioned hologram element is an integrated optical element that converts the received light beam into Claim 30, characterized in that the focus is on a point substantially fixed to the An optical element of monolithic structure as described in Section 1. 32. The above means for moving the above hologram element includes moving the above hologram element. Claim 1 characterized in that it is constituted by holder means attached to 31. The monolithic optical element according to item 30. 33. The above hologram element converts the received light beam into an optical system of the above monolithic structure. Claims characterized in that focusing is performed at a substantially fixed point relative to the target element. 33. A monolithic optical element according to clause 32. 34. The movement of said holder means is fixed relative to said monolithic optical element. of the integral structure according to claim 32, characterized in that the optical element.