JP3571211B2 - Optical reader - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical reader. More specifically, the present invention relates to an improvement in the characteristics of a lens provided in an optical reading device for receiving reflected light from a subject and capturing an image signal.
[0002]
[Prior art]
As shown in FIG. 12, there is an optical reading device 101 that irradiates a subject and recognizes a surface pattern or the like of the subject, as illustrated in FIG. In this case, the light emitted from the irradiating means 102 irradiates the subject 103 from the outside, reflects the light, passes through the lens 105, forms an image by the image sensor 104, and is read as an image signal.
[0003]
[Problems to be solved by the invention]
However, when the subject 103 is illuminated using the ring-shaped irradiating means 102 in this manner, the periphery is more strongly illuminated than the center thereof, and thus the light amount distribution becomes uneven as shown in FIG. There is a problem that an image with an unusual illumination cannot be obtained. In this case, this may be used as long as only the outer shape of the subject 103 is captured. However, when the image of the subject 103 such as a coin is read, it is necessary to read the surface pattern. There is a need for processing in circuit and electric systems. Therefore, in such an optical reader 101, it is necessary to provide a correction circuit as well.
[0004]
On the other hand, in the optical reading apparatus 101 having such a configuration, a lens having a flat characteristic is generally used as the lens 105. If the lens 105 can correct the light amount distribution, a circuit system or an electric It is not necessary to provide a correction circuit such as a system.
[0005]
Accordingly, it is an object of the present invention to provide an optical reader in which light amount distribution correction can be performed by a lens.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, an irradiating means for irradiating a subject through an optically transparent body, and a lens for receiving reflected light from the subject by the irradiating means and capturing the reflected light as an image signal An optical reading device comprising: an optical reading device having an optical reading device having a circular shape on an image capturing surface of an optically transparent body for capturing an image of a subject, and an irradiation device configured to surround the image capturing surface. Arranged in a circular shape and configured to irradiate the image capturing surface obliquely from the outer peripheral side, As a lens, Offset increase in peripheral light quantity by irradiation means that irradiates obliquely from the outer peripheral side To obtain a light distribution with flat characteristics Reduced peripheral light intensity characteristics Adopt lens are doing.
[0007]
In this case, when the subject is irradiated to the irradiation unit on the image capturing surface, the irradiation light is reflected in a state in which the peripheral light amount is increased because the irradiation is performed obliquely from the outer peripheral side. Since the reflected light passes through the lens whose peripheral light quantity characteristic has been reduced, the light quantity characteristic is corrected at this time, and the reflected light is taken into the imaging device or the like in a state where the increased peripheral light quantity characteristic is canceled.
[0008]
In the optical reading apparatus according to the second aspect of the present invention, a circular opening is provided in a front frame to which the optical transparent body is attached, and a passage through which a subject to be image-read passes through one side of the optical transparent body. On the other hand, irradiation means for irradiating the object on the other side of the optically transparent body is provided so as to surround the opening of the front frame. Therefore, the subject is illuminated by the irradiating means when passing through this passage, and since this irradiating light is radiated obliquely to the subject from the outer peripheral side, it is reflected from the subject in a state where the peripheral light amount is increased. ing.
[0009]
In the optical reader according to the third aspect of the present invention, the irradiating means is constituted by arranging a large number of light emitting diodes emitting infrared light in a circular shape. The infrared light emitted from the light emitting diode is obliquely applied to the subject from the outer peripheral side, and the reflected light having the increased peripheral light amount characteristic passes through the lens.
[0010]
In the optical reading device according to the fourth aspect of the present invention, the light distribution characteristics of the lens are such that the light distribution characteristics of the irradiation by the large number of light emitting diodes are changed on the imaging surface of the imaging element that receives the light imaged by the lens. It is intended to have uniform characteristics. Therefore, in this case, even if the peripheral light amount characteristic is increased by being illuminated from the outer peripheral side by a large number of light emitting diodes, the reflected light has a uniform light amount characteristic at the stage where an image is formed by passing through this lens. It is corrected so that
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail based on an example of an embodiment shown in the drawings. 1 to 8, 10 and 11 show an embodiment of the optical reader 1 of the present invention. The optical reader 1 includes an irradiating unit 33 that irradiates a light beam to the subject 13 through the optical transparent body 2 and an optical reading unit 4 that captures an image of the subject 13 by reflecting the light beam through the optical transparent body 2. And In the present embodiment, the optical reader 1 reads a pattern of a coin as the subject 13 and uses the coin for determining the type and authenticity of the coin. However, the use of the optical reader 1 is not limited to coin reading.
[0012]
The optical reader 1 is provided with an anti-reflection film 48 on the surface of the optical transparent body 2 opposite to the surface facing the subject 13 to prevent reflection of light having a different wavelength from the irradiation light of the irradiation unit 33. ing. Since the antireflection film 48 has a peak wavelength different from the peak wavelength of the irradiation light of the irradiation unit 33, the irradiation light generated by the irradiation unit 33 is internally reflected inside the optical reader 1. Can be suppressed. This makes it possible to suppress the occurrence of ghosts and flares in the image read by the optical reading unit 4.
[0013]
In the present embodiment, the irradiation unit 33 has a peak wavelength of about 950 nm by using an LED that emits infrared light. Further, the antireflection film 48 provided on the inner side surface of the optically transparent body 2 is formed by coating the optically transparent body 2 with magnesium fluoride. In the present embodiment, the anti-reflection film 48 is formed by coating with magnesium fluoride. However, the present invention is not limited to this, and an existing or new material used as the anti-reflection film can be used.
[0014]
The peak wavelength of the anti-reflection film 48 can be adjusted according to the thickness of the film. In the present embodiment, the thickness of the anti-reflection film 48 is set so that the anti-reflection film 48 has a peak wavelength of about 600 nm. Therefore, by setting the peak wavelengths of the irradiation unit 33 and the antireflection film 48, the internal reflection in the optical reader 1 can be suppressed. In the present embodiment, the peak wavelength of the irradiation means 33 is set to about 950 nm and the peak wavelength of the antireflection film 48 is set to about 600 nm. However, the present invention is not limited to this, and the wavelengths of the irradiation means 33 and the antireflection film 48 are made different. Just do it. That is, by making the peak wavelengths of the irradiation unit 33 and the antireflection film 48 different, the internal reflection in the optical reader 1 can be suppressed.
[0015]
The optically transparent body 2 is made of sapphire glass. For this reason, since the optical transparent body 2 can have high hardness, even if the object 13 which is a metal coin is slid on the optical transparent body 2, the wear of the optical transparent body 2 can be suppressed. it can.
[0016]
The optically transparent body 2 is attached to a circular opening 62 provided in the front frame 14. One side of the optically transparent body 2 is a passage 32 through which the subject 13 from which an image is to be read passes, and the subject 13 slides on the surface thereof. Further, the optical transparent body 2 is supported by a guide member 14 supported by the main body frame 3 so as to be located at the center of the upper part of the optical reader 1. The guide member 14 functions as a front frame of the optical reader 1, and has a circular opening 62 having a smaller diameter than the optical transparent body 2. An annular visual field mask 54 is provided on the inner surface of the optically transparent body 2. For this reason, the shape of the image capturing surface 50 from which the optical transparent body 2 can capture the image of the subject 13 is circular. In the present embodiment, the visual field mask 54 provided on the inner side surface of the optically transparent body 2 has an annular shape. However, the present invention is not limited to this.
[0017]
Further, in the optical transparent body 2 provided for capturing an image of the subject 13, the image capturing surface 50 has a circular shape. Therefore, the area of the expensive sapphire glass can be minimized, so that the manufacturing cost can be reduced and the sapphire glass can be hardly damaged. Further, guide plates 34, 34 functioning as passage members for forming the passage 32 are disposed before and after the circular optical transparent body 2 in the traveling direction of the subject 13. Each guide plate 34 has an arc-shaped concave portion that matches the outer edge of the optically transparent body 2 and is formed so as to have a square shape that matches the shape of the case body 5 as a whole. The guide plate 34 is supported by the guide member 14 with the concave portion aligned with the optically transparent body 2. For this reason, the guide member 14 can be made of, for example, a metal and subjected to a nitriding treatment or the like and cured, so that abrasion of the passage 32 due to sliding of the subject 13 can be reduced. In this embodiment, the optical transparent body 2 is circular and the guide plates 34 are provided before and after the optical transparent body 2. However, the present invention is not limited to this, and the optical transparent body 2 may be rectangular and cover the entire surface of the inner body 15. good.
[0018]
Furthermore, a taper is formed at the edge of the surface of the optical transparent body 2 and each guide plate 34. Therefore, when the subject 13 slides along the optically transparent body 2 and the respective guide plates 34, 34, it is possible to prevent the subject 13 from being caught at the boundary between the optically transparent body 2 and the respective guide plates 34, 34. it can.
[0019]
The irradiating unit 33 is provided on the other side of the optically transparent body 2, that is, on the side opposite to the passage 32 through which the subject 13 passes, so as to surround the opening 62 of the front frame 14. The main body frame 3 of the optical reading device 1 is supported via an LED board 49 so as to irradiate a visual field. That is, the irradiating means 33 is arranged in a circular shape so as to surround the image capturing surface 50 and is configured to irradiate the image capturing surface 50 obliquely from the outer peripheral side. That is, a plurality are arranged so as to surround the visual field frame. The irradiation unit 33 in the present embodiment is configured by arranging a large number of light emitting diodes that emit infrared light in a circular shape.
[0020]
An annular prism 51 that covers the upper side of the irradiation unit 33 is attached to the LED substrate 49. The prism 51 transmits and reflects the light beam of the irradiation unit 33 radiated upward so as to irradiate the image capturing surface 50 obliquely from the outer peripheral side.
[0021]
Further, the light beam emitted from the prism 51 passes through the diffusion plate 55 and irradiates the optically transparent body 2. For this reason, the optical transparent body 2 can be uniformly irradiated. Then, a light beam from the irradiating unit 33 passes through the optically transparent body 2 to irradiate the subject 13, and the reflected light passes through the optically transparent body 2 and is taken into the optical reading unit 4.
[0022]
The optical reading means 4 is supported by an optical support frame 63 integrally connected to the main body frame 3, and receives a reflected light from the subject 13 which is transmitted through the optically transparent body 2 and forms an image by capturing the reflected light. And an image sensor 42 composed of, for example, a CCD for converting the formed image into an electric signal. The image pickup device 42 is attached to a CCD substrate 43 fixed to the main body frame 3.
[0023]
The CCD substrate 43 is disposed so as to be parallel to the optically transparent body 2, and is fixed to the main body frame 3. A circuit serving as an image conversion circuit section 61 for converting and outputting signals is provided on the CCD board 43. Therefore, the CCD board 43 serves as a circuit holding section for holding the image conversion circuit section 61. Play.
[0024]
On the other hand, the circuit section 12 according to the present embodiment includes an amplifier circuit section 56 and a control circuit section 57. The amplifier circuit section 56 is held on the AMP board 58, and the control circuit section 57 is held on the control board 59. I have. Therefore, the AMP board 58 and the control board 59 each serve as a circuit holding section for holding a circuit. In the present embodiment, both substrates 58 and 59 are provided along the case body 5 (in this case, specifically, the side portion 52 of the case body 5) so as to be orthogonal to the CCD substrate 43, and the internal body Effective use of the space on the 15 sides is achieved. Therefore, the amplification circuit section 56 and the control circuit section 57 are arranged orthogonally to the above-described image conversion circuit section 61, and the amplification circuit section 56 and the control circuit section 57 in the present embodiment take a large space. As shown in FIG. 10, two flexible cables 60, 60 are connected. Therefore, the board (CCD board 43, AMP board 58, and control board 59) and the flexible cables 60, 60 have a box-like shape on the other five surfaces except the optically transparent body 2 side when viewed from the body frame 3. Since they are arranged, the space between the case body 5 and the inner body 15 can be effectively used.
[0025]
The lens group 41 lowers the peripheral light amount characteristic of the lens so as to offset the increase in the peripheral light amount by the irradiation unit 33 that irradiates the light obliquely from the outer peripheral side. In other words, the light is reflected by passing through this lens. The peripheral light amount of the light is made dark. In this case, the lens group 41 held by the mirror copper 35 may be configured so that the amount of peripheral light becomes dark by combining, for example, a lens formed in a convex shape, or the surface is coated. A desired light amount distribution may be obtained by combining the selected lenses. According to the lens group 41 configured in this way, as shown in FIG. 11, even if the periphery is brightened by the irradiation unit 33, the peripheral light amount characteristic is further reduced by further passing through the lens group 41, In the image sensor 42, a good image with a flat light amount can be obtained. Since the light distribution characteristics of the lens are such that the light distribution characteristics of irradiation by a large number of light-emitting diodes are uniform on the imaging surface of the imaging element 42 that receives the light imaged by the lens, Needless to say, the lens characteristics of the lens group 41 are appropriately set according to the light amount characteristics of the irradiation unit 33 so as to obtain a flat light amount in the image sensor 42.
[0026]
The mirror copper 35 is held by the lens support frame portion 36. The lens support frame 36 is formed integrally with the main body frame 3. The lens support frame portion 36 holds the lens group 41 at the center via the mirror copper 35. Here, a wide-angle lens is used as the lens group 41. For this reason, the focal length of the lens group 41 can be shortened, so that the entire length of the optical reader 1 can be shortened, and the size and weight can be reduced.
[0027]
An annular visual field mask 37 surrounding the optical path is attached to the upper part of the lens support frame part 36. The inner edge of the visual field mask 37 prevents the peripheral edge of the optically transparent body 2 from being reflected. Since the visual field mask 37 is provided at a position close to the lens group 41, the visual field mask 37 can be made smaller than that provided near the optical transparent body 2, and the peripheral edge of the optical transparent body 2 is prevented from being reflected. Thus, the unevenness of the subject 13 can be clearly recognized.
[0028]
On the side of the lens support frame portion 36, a detection sensor 40 composed of, for example, a phototransistor for detecting that the subject 13 is present on the upper surface of the optically transparent body 2 is provided. An LED 39 that emits a light beam toward the detection sensor 40 is provided outside the device on the incident axis of the detection sensor 40 (upper part in FIG. 1). When the light from the LED 39 passes through the optically transparent body 2 and enters the detection sensor 40, it is detected that the subject 13 is not at a predetermined position, and conversely, the light from the LED is blocked by the subject 13. Therefore, when the light does not enter the detection sensor 40, it is detected that the subject 13 is at a predetermined position. Here, since the visual field mask 37 is located at a position close to the lens group 41, the optical path from the LED 39 outside the device to the detection sensor 40 is not blocked.
[0029]
The LED 39 is provided as a sensor light source separately from the irradiation unit 33, and emits sensor light toward a detection sensor (phototransistor) 40. In the present embodiment, the phototransistor 40 provided as a light receiving element for detecting sensor light is attached to the optical support frame 63 so as to be adjacent to the optical reading means 4 and, together with the optical reading means 4, emits light from the same direction. It is designed to receive light. In this case, the phototransistor 40 is provided so as to have a light receiving wavelength range different from the light receiving wavelength range of the optical reading unit 4. For example, in the present embodiment, an LED that emits sensor light in a red light region is used as the LED 39, and this red light is used to detect the position of the subject 13. On the other hand, an infrared light beam is used as image signal light. ing.
[0030]
In this manner, the phototransistor 40 and the optical reading means 4 have different light receiving wavelength ranges, and the optical element surface of the optical reading means 4 is coated with a coating for cutting the wavelength of sensor light. In this case, the optical element is either a lens group 41 that forms an image of the reflected light from the subject 13 or a transparent member that surrounds an imaging element 42 that receives the light formed by the lens group 41. Although not shown, the transparent member is provided to protect the light receiving surface with a transparent member such as glass so as to prevent dust and the like from entering the element surface of the image sensor 42. In this embodiment, the lens group 41 is composed of five lenses. When coating the lens group 41, it may be applied to only one lens or may be applied to a plurality of lenses. .
[0031]
In the present embodiment, this coating is provided so as to transmit only infrared light serving as an image signal, and prevents light in a visible light region including a red region and a part in an ultraviolet region from being incident on the image sensor 42. In the present embodiment, magnesium fluoride is used as a coating material for this purpose, but the coating material is not particularly limited as long as it exhibits the above-described functions.
[0032]
The optical reader 1 includes an optical reader 4 for taking in image data into the apparatus via an optical transparent body 2 and a case body 5 containing therein a circuit section 12 for operating the optical reader 4. It has. The case body 5 is formed so as to seal the optical path between the optical reading means 4 and the optically transparent body 2 and the optical reading means 4 and the circuit section 12. In the present embodiment, the circuit section 12 has two circuit boards (AMP board 58 and control board 59), and the optical reading means 4 has a lens group 41, an image sensor 42, and a CCD board 43. . The lens group 41 and the CCD substrate 43 of the optical reading means 4 and the substrate of the circuit section 12 are fixed to the main body frame 3 and the optically transparent body 2 is fixed to the main body frame 3 via the guide member 14. Accordingly, the optical reading means 4, the circuit section 12, the main body frame 3, the guide member 14, and the optically transparent body 2 are integrated as a whole to form an internal body 15.
[0033]
The case body 5 is made of metal and has a rectangular parallelepiped shape whose upper side is open. The attachment between the case body 5 and the inner body 15 is performed by fitting the open end 53 of the case body 5 to the step 6 on the outer periphery of the guide member 14 of the inner body 15.
[0034]
In the optical reader 1, a connector for electrically connecting the circuit section 12 to the outside of the case body 5 is attached to a packing support section 17 located around an externally exposed section 19 of the connector section. The unit body 16 is formed. The bottom 20 of the case body 5 has an opening 21 formed of a through-hole for exposing the externally exposed portion 19 to the outside of the case body 5. In the present embodiment, the opening 21 is formed in the bottom portion 20 of the case body 5, but is not limited thereto, and may be formed in the side portion 52 of the case body 5. Further, in the present embodiment, the connector portion is formed by the unit body 16 in which the packing member 18 is attached to the packing support portion 17, but is not limited thereto.
[0035]
Further, the unit body 16 is fixed to the inside of the case body 5 so that the externally exposed portion 19 is exposed to the outside from the opening portion 21 and the packing member 18 is pressed between the case body 5 and the packing support portion 17. I am trying to do it. The packing member 18 is made of an elastic material such as rubber, and in this embodiment, is a plate having a through hole in the center. A commercially available O-ring or the like may be used as the packing member 18.
[0036]
For this reason, since the connector portion is formed by the unit body 16 including the packing member 18, the connector portion can be attached to and detached from the case body 5 with a general-purpose screw member or the like. Accordingly, the case body 5 can be easily removed from the main body 15 without using a dedicated jig. Also, since the packing member 18 is sandwiched and pressed between the case body 5 and the packing support part 17, the sealing performance between the case body 5 and the connector part can be improved, and the connection between the case body 5 and the connector part can be improved. Sealing can be performed without using a sealing agent therebetween. Therefore, when the case body 5 is detached from the main body frame 3, the sealant between the connector portion and the case body 5 is not broken, so that generation of dust and dirt can be prevented. In addition, since no sealant is used between the case body 5 and the connector portion, the appearance can be improved, and it is not necessary to carefully apply the sealant while paying attention to the deterioration of the appearance. Workability can be improved.
[0037]
Here, the unit body 16 includes a connector socket 19 to which an external connector of the case body 5 connectable to the connector portion is connected and which forms an externally exposed portion, and a connector board 22 connected and fixed to the connector socket 19. A connector 23 for fixing the connector socket 19 and the connector board 22 to the case body 5 and having a packing support portion 17; and a packing member 18 attached to the packing support portion 17 on the outer periphery of the connector socket 19. The holder 23 includes a housing hole 24 for housing the connector socket 19, a concave packing support portion 17 formed at an edge of the housing hole 24 on a surface facing the inner surface of the case body 5 and housing the packing member 18, A substrate fixing hole 26 for screwing the substrate 22 to the holder 23 with a bolt 25 and a holder fixing hole 28 for screwing the holder 23 to the case body 5 with a bolt 27 from outside the case body 5 are provided. I have.
[0038]
The connector socket 19 is connected and fixed to the connector board 22 by soldering. The connector board 22 to which the connector socket 19 is fixed is screwed to the holder 23 with the connector socket 19 housed in the housing hole 24 of the holder 23. Here, a sealant 29 is applied to the contact portion between the holder 23 and the connector board 22 from the outer peripheral side. As the sealant 29, for example, an adhesive made of a synthetic resin can be used. Therefore, sealing can be performed between the holder 23 and the connector board 22.
[0039]
Further, a packing member 18 is provided so as to surround the outer periphery of the connector socket 19. The packing member 18 is housed in the packing support 17. Then, the holder 23 is screwed to the case body 5 from the outside of the case body 5 with the distal end of the connector socket 19 being exposed from the inside of the case body 5 through the opening 21 to the outside. Therefore, the packing member 18 can be crushed between the case body 5 and the holder 23 to achieve sealing. Moreover, since the packing member 18 is provided on the outer periphery of the connector socket 19, the gap between the connector socket 19 and the packing member 18 can be sealed.
[0040]
The connector board 22 and the circuit section 12 are connected by, for example, a flexible cable 30. One end of the flexible cable 30 is directly soldered to the connector board 22, and the other end is connected to the board of the circuit section 12 via the cable socket 31.
[0041]
Here, when the holder 23 is pressed from the outside to the inside of the inner body 15, the holder 23 is in contact with the circuit portion 12 and the optical reading means 4 fixed to the main body frame 3 and remains outside the inner body 15. To prevent them from getting inside. Specifically, the holder 23 is made to abut on the circuit board of the circuit section 12 fixed to the main body frame 3 and the CCD board 43 of the optical reading means 4 fixed to the main body frame 3 in a loose state. Further, the connector board 22 is disposed so as to enter the inside of the CCD board 43. For this reason, it is possible to prevent the unit body 16 from falling off from the inner body 15 due to the connector board 22 abutting against the CCD board 43 from inside. For this reason, since the holder 23 is positioned by the respective substrates 12 and 43, workability can be improved when the case body 5 is put on the inner body 15 and the holder 23 is screwed.
[0042]
On the other hand, a step 6 is formed on the outer peripheral surface of the guide member 14. The open edge 53 of the case body 5 is fitted to the step 6. The contact surface 6 a of the step 6 against which the open edge 53 of the case body 5 abuts is perpendicular to the outer peripheral surface of the case body 5. Thereby, the positioning of the case body 5 can be performed reliably. The step 6 does not need to be continuously provided so as to go around the periphery of the main body frame 3, but only needs to be provided within a necessary and sufficient range for positioning the case body 5.
[0043]
In this embodiment, as shown in FIGS. 4 and 7, the step 6 has a shape in which a step is cut off at each central part of a pair of facing sides, so that the ground part 11 of the case body 5 is provided at the part. Is located. However, it is a matter of course that the shape is not particularly limited.
[0044]
On the other hand, the case body 5 is attached so as to cover the inner body 15. The case body 5 in the present embodiment is made of a steel plate, and four side portions 52,..., 52 are each bent perpendicularly to the bottom portion 20, and these side portions 52,. It is formed into a shape that is joined and has an open top.
[0045]
As shown in FIGS. 7 and 8, an abutting portion 7 abutting on the step portion 6 is provided at the open end 53 of the case body 5 so as to protrude upward. In this case, when the case body 5 is fitted to the guide member 14 and the butted portion 7 is brought into contact with the contact surface 6 a of the step portion 6, the butted portion 7 is other than the butted portion 7 of the open edge 53. A gap 8 is formed between the portion and the contact surface 6a.
[0046]
The butting portion 7 is formed in a trapezoidal shape protruding from the open end edge 53 of the case body 5, and furthermore, the case body 5 is screwed and fixed to the guide member 14 with the bolt 44 at the protruding portion. A screw hole 10 is provided. In this case, the four butting portions 7,..., 7 are provided so that the protruding amounts from the open edge 53 are equal at any positions, so that the case body 5 can be positioned accurately and well-balanced with respect to the guide member 14. Has been. However, the shape or form of the butting portion 7 is not limited to such a shape. For example, a semicircular shape or a triangular shape may be used to correctly position the case body 5 with respect to the guide member 14 as described above. There is no problem as long as the gap 8 is formed between the open edge 53 of the case body 5 and the contact surface 6a of the step portion 6. The case body 5 and the guide member 14 are fixed by screwing the screwed portion 10 of the butted portion 7 to the state where they are positioned as described above, and the optical reading device 1 is formed.
[0047]
The open end 53 of the case body 5 is provided with a ground part 11 for grounding the case body 5. The grounding portion 11 in the present embodiment is integrally formed with the case body 5 between the adjacent butting portions 7, and has a substantially L-shape protruding from the opening edge 53 beyond the butting portion 7. In this case, the ground portion 11 has a shape that becomes thinner toward the tip, and the upper portion of the tip has a pointed shape that maintains good contact and conductivity. For this reason, the ground part 11 has flexibility.
[0048]
When the case body 5 is attached to the main body frame 3 having a potential of 0 via the guide member 14, the tip of the ground portion 11 of the case body 5 contacts the frame of an optical device to which the optical reader 1 is attached. Will be in contact. Since the contacting grounding portion 11 is bent and pressed against a frame or the like of the optical device, the grounding state of the case body 5 is always maintained. It should be noted that the shape and form of the ground portion 11 shown here are merely examples, and are not particularly limited as long as the case body 5 can be sufficiently grounded.
[0049]
A gap 8 is provided by an abutting portion 7 between the open edge 53 of the case body 5 and the contact surface 6 a of the step portion 6. The gap 8 is coated with a sealant 9 for fixing the guide member 14 and the case body 5 and improving the sealing property. In the present embodiment, a curable resinous material having high viscosity is used as the sealant 9. In this case, since the sealant 9 may be applied to the gap 8, the sealant 9 can be evenly applied to the shape of the gap 8 visually. The sealant 9 may be applied entirely so as to fill the gap 8 between the main body frame 3 and the case body 5, but as in the present embodiment, the open edge 53 side of the case body 5 Even if it is applied to only the guide member 14, the sealing property between the guide member 14 and the case body 5 can be sufficiently maintained, so that the application amount can be reduced within a range in which the sealing property is maintained.
[0050]
In addition, since the sealing agent 9 is applied to the outer peripheral surface of the optical reader 1 in this manner, it is suitable for removing the case body 5 from the inner body 15. That is, the cured sealing agent 9 can be removed from the surrounding side by scraping or the like, so that the case body 5 can be easily removed from the inner body 15.
[0051]
When assembling the optical reader 1 described above, the unit body 16 of the connector section is attached to the circuit section 12 and the CCD board 43 when the internal body 15 is assembled. Then, the case body 5 is put on the inner body 15, and the holder 23 is screwed to the case body 5 with bolts 27 from outside the bottom 20 of the case body 5. Then, the butting portion 7 of the case body 5 is screwed to the guide member 14 and the sealant 9 is applied to the open end 53. Thus, the optical reader 1 is assembled.
[0052]
When removing the case body 5 from the inner body 15, the sealing agent 9 on the open edge 53 is removed, and the butt 7 and the bolts 44 and 27 on the bottom 20 are removed. As a result, the case body 5 is no longer fixed to the inner body 15 and can be easily removed from the inner body 15.
[0053]
Further, when the image of the subject 13 is captured by the above-described optical reading device 1, irradiation light is generated by the irradiation unit 33 and transmitted through the prism 51 and the diffusion plate 55. The transmitted light passes through the optically transparent body 2 and irradiates the subject 13 to be reflected. The reflected light passes through the optically transparent body 2 again, enters the lens group 41, and is imaged by the image pickup device. The formed image is converted into an electric signal by the image sensor 42. Here, since the antireflection film 48 is formed on the inner side surface of the optically transparent body 2 and the peak wavelength of the antireflection film 48 is different from the peak wavelength of the irradiating means 33, the inside of the optical reader 1 is not changed. Internal reflection can be suppressed.
[0054]
Therefore, according to the optical reading device 1 of the present embodiment, since the irradiation light generated by the irradiation unit 33 can be prevented from being internally reflected inside the device, the ghost or the ghost in the image read by the optical reading unit 4 can be suppressed. The occurrence of flare can be suppressed. For this reason, the accuracy of the determination of the read image can be improved.
[0055]
Further, according to the optical reading device 1 of the present embodiment, since the wide-angle lens is adopted as the lens group 41 of the optical reading means 4, the distance between the optically transparent body 2 and the imaging element 42 is shortened, The size and weight of the reader 1 can be reduced. In this case, despite the use of a wide-angle lens that tends to have strong internal reflection, the irradiation light generated by the irradiation unit 33 is suppressed from being internally reflected inside the apparatus, so that the accuracy of determination of the read image is improved. Can be done.
[0056]
Further, according to the optical reader 1 of the present embodiment, since the connector portion is formed by the unit body 16 including the packing member 18, the connector portion is attached to and detached from the case body 5 by a general-purpose screw member or the like. can do. Thereby, the case body 5 can be easily removed from the main body 15 without using a dedicated jig.
[0057]
In addition, since the packing member 18 is sandwiched and pressed between the case body 5 and the packing support part 17, the sealing performance between the case body 5 and the connector part can be improved, and the case body 5 and the connector socket 19 Sealing can be performed without using a sealing agent during the process. Therefore, when the case body 5 is detached from the inner body 15, the sealing agent between the connector portion and the case body 5 is not broken, so that generation of dust and dirt can be prevented.
[0058]
In addition, since no sealant is used between the case body 5 and the connector socket 19, the appearance can be improved, and it is not necessary to carefully apply the sealant while paying attention to the deterioration of the appearance, so that the assembling can be performed. Workability can be improved.
[0059]
In the optical reader 1 of the present embodiment, the gap 8 is formed between the step 6 and the open edge 53, and the gap 8 between the main body frame 3 and the case body 5 is sealed. It is sealed with the agent 9 to enhance the sealing property. Therefore, it is possible to prevent dust from entering the inside of the optical reader 1.
[0060]
Moreover, since the sealant 9 is applied from the outside after the case body 5 is assembled to the inner body 15, the amount of the sealant 9 can be adjusted while visually observing, and there is no extra application. Therefore, the sealant 9 does not protrude into the optical reader 1. Also, since the sealing agent 9 is applied later, less attention is required when assembling the case body 5 to the inner body 15. In other words, when attaching the case body 5 to the inner body 15 to which the sealing agent 9 has been applied in advance, the sealing agent 9 is spread over the portion where the gap 8 is formed without excess or shortage while preventing the sealing agent 9 from attaching to other portions. However, according to the present embodiment, the labor required for the mounting and the labor required for the application are small, and the labor required for the assembly is small.
[0061]
The above embodiment is an example of a preferred embodiment of the present invention, but the present invention is not limited to this, and various modifications can be made without departing from the gist of the present invention. For example, in the present embodiment, the holder 23 and the connector socket 19 are separate bodies, but the invention is not limited thereto, and the holder 23 and the connector socket 19 may be integrally formed by, for example, injection molding of plastic. In this case, the number of parts decreases.
[0062]
In the present embodiment, the connector is sealed when the inside and outside of the optical reading device 1 are connected by a connector. However, the present invention is not limited to this, and the cable is used to connect the inside and outside of the optical reading device 1 by a cable. Sealing structure.
[0063]
In this case, as shown in FIG. 9, the optical reader 1 has a drawer for drawing out a connection cable 45 for electrically connecting the circuit unit 12 to the outside of the case body 5 from the case body 5, It is formed by a unit body 16 'in which a packing member 18 is attached to a packing support portion 17 around the portion 46. Then, the unit body 16 ′ is fixed to the inside of the case body 5 so that the external exposure portion 46 is exposed to the outside from the opening portion 21 and the packing member 18 is sandwiched between the case body 5 and the packing support portion 17 and pressed against the case body 5. I do.
[0064]
For this reason, since the draw-out portion is formed by the unit body 16 'including the packing member 18, the draw-out portion can be attached to and detached from the case body 5 by a general-purpose screw member or the like. Accordingly, the case body 5 can be easily removed from the main body 15 without using a dedicated jig. Further, since the packing member 18 is sandwiched and pressed between the case body 5 and the packing support part 17, the sealing performance between the case body 5 and the draw-out part can be improved, and the connection between the case body 5 and the draw-out part can be improved. Sealing can be performed without using a sealing agent therebetween. Therefore, when the case body 5 is removed from the main body frame 3, the sealant between the drawer and the case body 5 is not broken, so that generation of dust and dust can be prevented. In addition, since no sealant is used between the case body 5 and the draw-out portion, the appearance can be improved, and it is not necessary to carefully apply the sealant while paying attention to the deterioration of the appearance. Workability can be improved.
[0065]
Further, the unit body 16 ′ includes a connection cable 45 electrically connected to the outside of the case body 5, the connection cable 45 held and fixed to the case body 5, and the concave packing support portion 17 and the case body 5. A holder 23 having an externally exposed portion 46 that is exposed to the outside, and a packing member 18 attached to the packing supporting portion 17 on the outer periphery of the externally exposed portion 46 are provided. For this reason, the connection cable 45 can be easily removed from the case body 5 and the sealant is not broken when the case body 5 is removed from the main body portion 15, thereby preventing generation of dust and dirt. can do. Further, a sealant 47 is applied between the connection cable 45 and the holder 23. Therefore, sealing between the connection cable 45 and the holder 23 can be performed.
[0066]
In each of the embodiments described above, the case where the sealing structure such as a connector is applied to an optical reader that reads a pattern such as a coin is described. However, the present invention is not limited to this. You may apply to an apparatus. Also in this case, the case body can be easily removed from the main body without using a dedicated jig, and at the time of removal, generation of dust and dust can be prevented.
[0067]
In each of the embodiments described above, the optical reader 1 is used for coin reading. However, the present invention is not limited to this. For example, the optical reader 1 can be used for fingerprint reading.
[0068]
【The invention's effect】
As is apparent from the above description, according to the optical reading apparatus of the first aspect of the present invention, the peripheral light amount characteristic of the lens is reduced so as to offset the increase in the peripheral light amount due to the irradiation unit. The distribution is corrected by a lens, and a light amount distribution with flat characteristics can be obtained in the image sensor. Thereby, a good image signal can be obtained without performing shading correction by a circuit system, an electric system, or the like.
[0069]
In the optical reader according to the second aspect of the present invention, a circular opening is provided in the front frame to which the optical transparent body is attached, and a passage through which a subject to be image-read passes through one side of the optical transparent body. On the other hand, irradiation means for irradiating the object on the other side of the optically transparent body is provided so as to surround the opening of the front frame. Therefore, the subject is illuminated by the irradiating means when passing through this passage, and the illuminating light is reflected from the subject and the peripheral light amount is increased.
[0070]
Further, in the optical reading device according to the third aspect of the present invention, since the irradiating means is constituted by arranging a large number of light emitting diodes emitting infrared light in a circular shape, the subject can emit red light emitted from the light emitting diodes. Irradiation is performed obliquely from the outer peripheral side by external light. Therefore, the reflected light from the subject passes through the lens with the peripheral light amount characteristic increased.
[0071]
In the optical reading device according to the fourth aspect of the present invention, the light distribution characteristics of the lens are set such that the light distribution characteristics of irradiation by a large number of light emitting diodes are made uniform on the imaging surface of the imaging element. The reflected light radiated from the outer peripheral side by the light emitting diode and having increased peripheral light amount characteristics can be corrected to a uniform light amount characteristic by passing through this lens.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional side view showing an embodiment of an optical reading device of the present invention.
FIG. 2 is an enlarged sectional view showing a connector section of the optical reader.
3A and 3B are views showing a unit body, wherein FIG. 3A is a front view, and FIG. 3B is a cross-sectional view taken along line BB of FIG. 3A.
FIG. 4 is a plan view showing the optical reader.
FIG. 5 is a side view showing the optical reader.
FIG. 6 is a bottom view showing the optical reader.
FIG. 7 is another side view showing the optical reader.
FIG. 8 is a side view showing a case body.
FIG. 9 is an enlarged cross-sectional view showing another embodiment of the connector section of the optical reader.
FIG. 10 is a plan view showing an internal body of the optical reader.
FIG. 11 is a diagram illustrating a configuration for obtaining flat light distribution characteristics in an optical reading unit.
FIG. 12 is a schematic configuration diagram showing a conventional optical reading device.
FIG. 13 is a diagram showing a light amount distribution of a subject in a conventional optical reading device.
[Explanation of symbols]
1 Optical reader
2 Optical transparent body
4 Optical reading means
13 subject
14 Guide member (front frame)
32 passages
33 Irradiation means
41 lens group (lens)
50 Image capture surface
62 opening

Claims (4)

An optical reading apparatus comprising: irradiating means for irradiating a subject via an optical transparent body; and optical reading means having a lens for receiving reflected light from the subject by the irradiating means and capturing the reflected light as an image signal. In the above, the image capturing surface of the optically transparent body for capturing the image of the subject has a circular shape, and the irradiating means is arranged in a circular shape so as to surround the image capturing surface. The surface is configured to irradiate obliquely from the outer peripheral side, and as the lens , the peripheral light amount characteristic is increased to such an extent that a flat light amount distribution can be obtained by canceling the increase in the peripheral light amount by the irradiation unit that irradiates obliquely from the outer peripheral side. An optical reading device characterized by employing a lens with reduced image quality. A circular opening is provided in a front frame to which the optically transparent body is attached, and one side of the optically transparent body is a passage through which the subject whose image is to be read passes, while the other side of the optically transparent body is provided. 2. The optical reading device according to claim 1, wherein an irradiating means for irradiating the subject to the side is provided so as to surround an opening of the front frame. 3. The optical reader according to claim 1, wherein the irradiating unit is configured by arranging a large number of light emitting diodes that emit infrared light in a circular shape. The light distribution characteristics of the lens are such that the light distribution characteristics of irradiation by the large number of light emitting diodes are uniform on an imaging surface of an imaging element that receives light formed by the lens. 4. The optical reader according to claim 3, wherein:

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