JP3675360B2 - Bar code reading optical device and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a barcode reading optical device and a method for manufacturing the same, and more particularly to an improved technique for improving the degree of freedom of design and positioning accuracy of an integrally formed light projecting lens and light receiving lens.
[0002]
[Prior art]
In recent years, in many stores and factories, bar codes representing digital information are attached to articles, and this is optically scanned to read information, thereby performing product sales management, product production management, etc. . In general, this type of barcode reads information from the combination of detection signals by irradiating the barcode with light and photoelectrically converting the intensity of the reflected light.
[0003]
That is, as shown in the conceptual diagram of FIG. 7, the light from the light emitting element 1 is stopped by the light emitting lens 3, the light is reflected by the mirror 7 of the scan mirror 5, and is irradiated onto the barcode 9. In order to irradiate light over the entire area of the bar code 9, the mirror 7 is swung. For swinging, the magnet 11 attached to the mirror 7 is inserted into the drive coil 13, and positive and negative currents are passed through the drive coil 13 at a constant cycle, for example, to attract and repel the magnet 11 with respect to the drive coil 13. The mirror 7 is swung with the moving fulcrum 15 as a support shaft.
[0004]
On the other hand, the light irradiated onto the surface of the barcode 9 is reflected back to the mirror 7 with a change in the amount of light of the barcode black and white while being irregularly reflected, and the reflected light is condensed by the condenser lens 17 and the amount of light is changed by the light receiving element 19. Is electrically converted and output. In order to improve the reading accuracy, a band pass filter (BPF) 21 is provided on the front surface of the light receiving element 19 to prevent unnecessary light from being collected other than the emitted light frequency.
[0005]
An optical apparatus for reading a barcode shown in FIG. 8 is provided as an apparatus incorporating such a reading method. As shown in the figure, the configuration of this apparatus is a light emitting mechanism A in which the light emitting element 1 and the light emitting lens 3 are housed in a casing 25, and a light receiving mechanism B in which the light receiving element 19, the light receiving lens 17, and the BPF 21 are housed in a casing 27. Are mounted on the substrate 29.
The electrical connection in each casing 25, 27 is performed by wire bonding or the like. The mirror 7 of the scan mirror 5 is arranged so as to be able to oscillate about the oscillating fulcrum 15. The light emitting mechanism A, the light receiving mechanism B, and the scan mirror 5 are housed in a housing (not shown) and are formed as a barcode reading optical device.
[0006]
[Problems to be solved by the invention]
However, the above-described optical device for reading a barcode has a large mounting space because the light emitting mechanism in which the light emitting element and the light emitting lens are housed in the casing and the light receiving mechanism in which the light receiving element and the light receiving lens are housed in the casing are configured separately. Therefore, there was a limit to downsizing the entire device.
On the other hand, in order to solve such a problem, it is described in Japanese Patent Application Laid-Open No. 7-93454 that attempts to achieve downsizing of the entire apparatus by integrating two lens portions into one transparent lens. As disclosed in Japanese Patent Application Laid-Open No. 11-15910, which is intended to reduce the number of optical components by reducing the number of optical components by integrally forming a bar code reader or an irradiation lens and an imaging lens with a transparent resin material. There is a “bar code reader”.
However, although these devices can achieve a certain amount of space saving, since the light projecting lens portion and the light receiving lens portion are integrally formed in the same medium, such as transparent resin, A different medium could not be selected. In addition, it is difficult to make any lens a compound lens, or to apply a different coating or the like for each lens, which limits the lens design. Furthermore, in the case of this type of integrally molded lens, if one lens is positioned and fixed, the other lens cannot move, and high precision is achieved by finely adjusting both the light projecting and light receiving lenses. Positioning could not be performed.
The present invention has been made in view of the above circumstances, and can improve the degree of freedom of design of each lens while ensuring miniaturization and weight reduction, and also allows the position of each lens to be freely adjusted. It is an object of the present invention to provide an optical device for reading a barcode and a manufacturing method thereof.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, an optical apparatus for reading a barcode according to claim 1 of the present invention, a light projecting lens for converging the light from the light emitting element and irradiating the barcode, an incident surface and an emission surface of the light A light-receiving lens that has a through-hole penetrating the surface and that inserts the projection lens into the through-hole and focuses the reflected light from the barcode; and receives the light focused by the light-receiving lens for photoelectric conversion A prismatic heat sink arranged so that the optical axis of the light receiving lens coincides with the axis, the light receiving element is fixed to an end surface of the heat sink, and an orthogonal plane different from the end surface is provided. The light emitting element is fixed to a side surface of the heat sink.
[0008]
In this barcode reading optical device, a through hole is formed in the light receiving lens, and the light projecting lens is inserted into the through hole, so that the light receiving lens installation space includes the light projecting lens installation space. . That is, it is not necessary to secure an installation space for each lens, and the size and weight can be reduced. In addition to this, material selection for each lens suitable for performance, coating processing, and the like can be performed, which increases design flexibility. In addition, since the relative positions of the light projecting lens and the light receiving lens can be adjusted independently, the positional error of each lens with respect to each element (light emitting element, light receiving element) can be reliably absorbed.
Furthermore, since the light receiving element fixed to the end face of the heat sink faces the light receiving lens on the optical axis of the light receiving lens, the focused light from the light receiving lens can be received efficiently. On the other hand, by fixing the light emitting element to the side surface of the heat sink, the light from the light emitting element does not enter the entire light receiving lens, and it is possible to irradiate only a part of the light receiving lens incorporating the light projecting lens. Therefore, the light emitted from the light emitting element and reflected by irradiating the barcode can be directly received by the light receiving element on the heat sink without requiring an angle conversion of 90 degrees by a mirror or the like.
[0009]
The optical device for reading a barcode according to claim 2 is characterized in that the projection lens is a compound lens in which a plurality of single lenses are combined.
[0010]
In this barcode reading optical device, the light projecting lens is a compound lens. This compound lens is formed by combining a plurality of single lenses. In this case, for example, if the light is propagated between the two lenses in a nearly parallel state, the tolerance of the axis deviation in the direction perpendicular to the optical axis is large, which is effective in improving the manufacturing yield and reliability.
[0011]
The optical device for reading a barcode according to claim 3, wherein the plurality of single lenses are fitted inside the cylinder so that the optical axis coincides with the axis, and the cylinder is inserted into the through hole of the light receiving lens. It is characterized by that.
[0012]
In this barcode reading optical device, a plurality of single lenses are fitted into a cylindrical body, and the cylindrical body is inserted into the through hole of the light receiving lens. A composite lens is manufactured by arranging and moving the cylinder relative to the through hole, so that the entire complex lens is moved relative to the light receiving lens, or the cylinder is fixed to the through hole. Thus, it is possible to perform a variation of position adjustment in which an arbitrary single lens is moved with respect to the cylindrical body.
[0013]
The optical device for reading a barcode according to claim 4 is characterized in that the cylindrical body is made of metal.
[0014]
In this barcode reading optical device, since the cylindrical body is made of metal, the light from the light emitting element incident on the compound lens does not propagate from the inner peripheral surface of the through hole to the medium of the light receiving lens. As a result, light from the light emitting element does not enter the light receiving element as a disturbance. That is, the light receiving accuracy of the reflected light by the light receiving element is increased.
[0015]
The optical device for reading barcode according to claim 5 is characterized in that the projection lens is a cylindrical single lens.
[0016]
In this bar code reading optical device, the projection lens is a cylindrical single lens, so that it is easier to manufacture than the above-described compound lens. Moreover, since it is cylindrical, the projection lens itself can be inserted into the through-hole, and the projection lens can be moved in the optical axis direction without using other members (for example, the above-described cylindrical body). Can be assembled to the light receiving lens.
[0017]
According to a method of manufacturing an optical device for reading a barcode according to claim 6, a prismatic heat sink is disposed so that an optical axis of the light receiving lens coincides with an axis, and a light receiving element is fixed to an end surface of the heat sink. A manufacturing method of an optical device for reading a barcode in which a light emitting element is fixed on a side surface of the heat sink, which is an orthogonal plane different from an end surface, and is projected into a through-hole that penetrates an incident surface and an output surface of the light receiving lens. A lens is movably fitted in the optical axis direction, the light receiving lens is positioned and fixed with respect to the light receiving element, and then the light projecting lens is moved and adjusted with respect to the light receiving lens positioned and fixed. It is characterized by.
[0018]
In this manufacturing method, the light receiving lens is positioned and fixed with respect to the light receiving element, and then the light projecting lens is moved and adjusted with respect to the light receiving lens to be positioned and fixed. The position of the received light receiving lens does not change. That is, each lens can be positioned at an optimum position. As a result, it is possible to perform a fine position adjustment for each lens, which cannot be performed with a conventional integrally molded lens.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a barcode reading optical device and a manufacturing method thereof according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a cross-sectional view of an essential part of a barcode reading optical apparatus according to the present invention, and FIG. 2 is a front view of the barcode reading optical apparatus shown in FIG.
[0020]
The barcode reading optical device (hereinafter referred to as “scan engine”) 31 according to the present embodiment has a structure in which a light emitting mechanism and a light receiving mechanism, which are conventionally separate, are integrated. That is, on one surface of the disk-shaped substrate 33, a prismatic heat sink 35 having an axis line aligned with the center of the substrate is fixed. The heat sink 35 is electrically connected by a heat sink lead 37 a penetrating the substrate 33.
[0021]
A light receiving element 39 is fixed to the end surface of the heat sink 35 opposite to the substrate fixing surface. The light receiving element 39 mainly receives light from the front in the axial direction of the heat sink 35 and operates to perform photoelectric conversion. The light receiving element 39 is electrically connected by a bonding wire 41 to a light receiving element lead 37 b penetrating the substrate 33.
[0022]
On the other hand, a light emitting element 43 is fixed on the side surface of the heat sink 35. Therefore, the light emitting element 43 and the light receiving element 39 are disposed on different orthogonal planes forming an angle of 90 degrees. The light emitting element 43 is also electrically connected to the light emitting element lead 37c penetrating the substrate 33.
[0023]
A cylindrical casing 45 having substantially the same outer diameter as the substrate outer diameter is fixed to the surface of the substrate 33 on the heat sink fixing side with the same central axis. That is, the heat sink 35, the light receiving element 39, and the light emitting element 43 are accommodated inside the casing 45. A light receiving lens 47 having substantially the same outer diameter as that of the casing 45 is fitted to the opening end of the casing 45 (the right end in FIG. 1) so that the optical axis coincides with the axis of the heat sink 35. The light receiving lens 47 focuses reflected light from a barcode (not shown) to the light receiving element 39.
[0024]
3 is a single-part view of the light-receiving lens shown in FIG. 1 in partial cross-sectional view (a) and front view (b). FIG. 4 is a part of the light-receiving lens in which the light-projecting lens shown in FIG. FIG. 5 is a single product diagram showing a modified example of the projection lens in a side view (a) and a front view (b). In the light receiving lens 47, a through hole 51 that penetrates the light incident surface 47 a and the light emitting surface 47 b is formed in a portion facing the light emitting element 43 in parallel with the optical axis. A projection lens 53 is inserted into the through hole 51.
[0025]
The light projection lens 53 according to the present embodiment is a compound lens composed of a plurality of single lenses 55a and 55b. The single lenses 55a and 55b are accommodated inside the cylinder 57 with the optical axis aligned with the axis. The light projecting lens 53 is integrated into the light receiving lens 47 by inserting the cylindrical body 57 into the through hole 51. The light projecting lens 53 is configured so that light is propagated between the two single lenses 55a and 55b in a nearly parallel state, and has a large axis deviation tolerance in the direction perpendicular to the optical axis, thereby improving manufacturing yield and reliability. Is effective.
[0026]
In the light projecting lens 53, the cylindrical body 57 is loosely fitted in the through hole 51 so as to be movable in the axial direction before the assembly to the light receiving lens 47 is completed. Further, the light projecting lens 53 may be loosely fitted so that the single lenses 55 a and 55 b are movable with respect to the cylindrical body 57. As a result, the light projection lens 53 can be adjusted relative to the light receiving lens 47 within the range of movement of the cylinder 57. After the light projecting lens 53 is positioned at a predetermined position, the cylindrical body 57 or the single lenses 55a and 55b are fixed with an adhesive or the like.
[0027]
The light projecting lens 53 has a structure in which a plurality of single lenses 55a and 55b are fitted to a cylindrical body 57, and the cylindrical body 57 is inserted into the through hole 51 of the light receiving lens 47. The composite lens is manufactured by arranging 55a and 55b, and by moving the cylinder 57 with respect to the through hole 51, the entire complex lens can be moved relative to the light receiving lens 47, or the cylinder. In a state where 57 is fixed to the through-hole 51, it is possible to perform a variation of position adjustment in which arbitrary single lenses 55a and 55b are moved with respect to the cylindrical body 57.
[0028]
The cylinder 57 is preferably made of a metal material. Since the cylindrical body 57 is made of metal, the light from the light emitting element 43 incident on the light projecting lens 53 does not propagate from the inner peripheral surface of the through hole 51 to the medium of the light receiving lens 47. As a result, the light from the light emitting element 43 does not enter the light receiving element 39 as a disturbance. That is, the light receiving accuracy of the reflected light by the light receiving element 39 is increased.
[0029]
In order to manufacture the scan engine 31 configured as described above, first, the light receiving lens 47 is positioned and fixed with respect to the light receiving element 39. The positioning at this time can be performed, for example, by setting the height h of the heat sink 35 from the substrate 33 and the height H of the casing 45 to predetermined dimensions. Thereafter, the light projection lens 53 is moved and adjusted in the optical axis direction with respect to the light-receiving lens 47 which has been positioned and fixed. When the light projection lens 53 reaches a predetermined position, it is fixed to the through-hole 51 with an adhesive or the like.
[0030]
In addition, the light projecting lens 53 may be composed only of the cylindrical single lens 55c shown in FIG. If the light projecting lens 53 is constituted by such a single lens 55c, it is easier to manufacture than the compound lens. Moreover, since it is cylindrical, the projection lens itself can be inserted into the through-hole 51, and the projection lens 53 is moved in the optical axis direction without using other members (for example, the above-described cylindrical body 57). The light receiving lens 47 can be assembled with a flexible structure.
[0031]
FIG. 6 is a cross-sectional view showing an operation state of the scan engine of FIG.
In the scan engine 31 of the present embodiment, when the light emitting element 43 emits light by a light emission driving circuit (not shown), the light is focused by the light projecting lens 53 and emitted from the light emission side of the light projecting lens 53. This light irradiates a barcode (not shown) and becomes reflected light.
The light reflected by the barcode enters the light receiving lens 47 and is converged, and the light receiving element 39 receives the light.
The light receiving element 39 photoelectrically converts this light and outputs the barcode pattern as an electrical signal to the light receiving element lead 37b.
This output signal is processed by a computer (not shown) to decode the bar code information.
[0032]
As described above, according to the scan engine 31 described above, the through hole 51 is formed in the light receiving lens 47, and the light projecting lens 53 is inserted into the through hole 51. The installation space for the lens 53 is included. Therefore, it is not necessary to secure an installation space for each lens, and the size and weight can be reduced. In addition to this, it becomes possible to select a material for each lens suitable for performance, a coating process, and the like, thereby increasing the degree of freedom in lens design. Further, since the relative position of the light projecting lens 53 and the light receiving lens 47 can be adjusted, the position error of each lens (light projecting lens 53, light receiving lens 47) with respect to each element (light emitting element 43, light receiving element 39) is absorbed ( Fine adjustment).
[0033]
【The invention's effect】
As described above in detail, according to the barcode reading optical apparatus of the present invention, the through hole is formed in the light projecting lens, and the light projecting lens is inserted into the through hole. In addition to being able to achieve a reduction in size and weight, it becomes possible to select a material for each lens suitable for the performance and to perform a coating process, thereby improving the degree of freedom of design. In addition, since the relative position between the light projecting lens and the light receiving lens can be adjusted, the position error of each lens with respect to each element can be absorbed.
[0034]
According to the method for manufacturing a barcode reading optical device according to the present invention, the light receiving lens is positioned and fixed with respect to the light receiving element, and then the light projecting lens is moved and adjusted with respect to the light receiving lens to be positioned and fixed. The position of the light receiving lens previously positioned is not changed by the movement adjustment of the light projecting lens to be performed, and each lens can be positioned at the optimum position. As a result, subtle position adjustments that could not be performed with conventional integrally molded lenses can be performed on each lens, and while achieving compactness and weight reduction, the assembly accuracy of the optical device for barcode reading, The barcode reading accuracy can be improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an essential part of an optical apparatus for reading a barcode according to the present invention.
2 is a front view of the barcode reading optical device shown in FIG. 1. FIG.
3 is a single product view of the light receiving lens shown in FIG. 1 in partial cross-sectional view (a) and front view (b).
4 is a lens assembly diagram showing a light receiving lens in which the light projecting lens shown in FIG. 1 is incorporated, partially in a sectional view (a) and in a front view (b).
FIG. 5 is a single product diagram illustrating a modification example of the light projecting lens in a side view (a) and a front view (b).
6 is a cross-sectional view showing an operation state of the barcode reading optical device of FIG. 1. FIG.
FIG. 7 is a conceptual diagram illustrating a conventional optical reading method.
FIG. 8 is a cross-sectional view of a conventional barcode reading optical device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 9 ... Barcode, 31 ... Scan engine (Barcode reading optical device), 35 ... Heat sink, 39 ... Light receiving element, 43 ... Light emitting element, 47 ... Light receiving lens, 47a ... Incident surface, 47b ... Outgoing surface, 51 ... Through Hole 53: Projection lens 55a, 55b Single lens 57: Tube

Claims (6)

A light emitting element;
A light projection lens that focuses the light from the light emitting element and irradiates the barcode;
A light-receiving lens that has a through-hole that penetrates the light incident surface and the light-exiting surface, inserts the light projecting lens into the through-hole, and focuses the reflected light from the barcode;
A light receiving element that receives light focused by the light receiving lens and performs photoelectric conversion;
A prismatic heat sink is disposed so that the optical axis of the light receiving lens coincides with the axis, the light receiving element is fixed to an end surface of the heat sink, and the side surface of the heat sink, which is an orthogonal plane different from the end surface, An optical apparatus for reading a barcode, wherein a light emitting element is fixed.   2. The barcode reading optical apparatus according to claim 1, wherein the light projecting lens is a compound lens obtained by combining a plurality of single lenses.   3. The bar code according to claim 2, wherein the plurality of single lenses are fitted inside the cylinder so that the optical axis coincides with the axis, and the cylinder is inserted into the through hole of the light receiving lens. Optical device for reading.   4. The barcode reading optical device according to claim 3, wherein the cylindrical body is made of metal.   2. The barcode reading optical apparatus according to claim 1, wherein the light projecting lens is a cylindrical single lens. A prismatic heat sink is disposed so that the optical axis of the light receiving lens coincides with the axis, and a light receiving element is fixed to an end face of the heat sink, and a light emitting element is provided on a side surface of the heat sink that is an orthogonal plane different from the end face. A method of manufacturing a fixed barcode reading optical device,
A projection lens is fitted in a through-hole penetrating the incident surface and the emission surface of the light receiving lens so as to be movable in the optical axis direction,
After positioning and fixing the light receiving lens with respect to the light receiving element,
A method of manufacturing an optical apparatus for reading a barcode, wherein the light projection lens is moved and adjusted with respect to the light receiving lens positioned and fixed to be positioned and fixed.

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