JP2013138385A - Reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a peripheral part of an original platen from being reflected on a captured image.SOLUTION: A reader includes: a transparent original platen 4 on which an original 3 is placed; a housing 2 for supporting the original platen; an illumination device 5 for illuminating a reading face 3a of the original placed on the original platen; an imaging apparatus 6 for imaging the reading face of the original illuminated by the illumination device; a mirror 7 which reflects light from the reading face of the original and guides it to the imaging apparatus; and a shielding plate 53 for shielding light which is reflected at a peripheral part of the original platen in the housing and advances to a direction of the mirror. Especially, the illumination device and the imaging apparatus are arranged below one end side of the original platen. The mirror is installed in a state where it is inclined to the original platen so that a reflection surface faces the original platen and the imaging apparatus below an other end side of the original platen. The shielding plate is disposed on one end side of the original platen.

Description

  The present invention relates to a reading apparatus that places an original on a transparent original table and illuminates a reading surface of the original with an illuminating device to capture an image of the original.

  2. Description of the Related Art Reading apparatuses for reading an image of a document are widely configured to illuminate a reading surface of a document placed on a transparent document table (platen glass) from below with an illuminating device and to make the reflected light enter an imaging device. It is popular. A reading apparatus equipped with such a document table is suitable for reading a document (form) formed by binding a plurality of sheets such as a passport, but captures reflected light on the reading surface of the document. In order to form an optical path leading to the apparatus, the housing tends to be enlarged. Therefore, a technique is known in which the optical path that guides the reflected light on the reading surface of the document to the image pickup device is bent by a mirror to reduce the size of the device (see Patent Document 1).

  In addition, when an LED element is used as the light source of the illumination device, the LED element becomes a point light source. Therefore, it is necessary to devise so as to obtain a uniform illuminance distribution on the reading surface of the document. A technique for using a body to function as a line light source is known (see Patent Document 2). With this technique, a uniform illuminance distribution can be obtained with a small number of LED elements.

JP 2010-2000187 A JP 2010-146868 A

  Now, in a reading apparatus provided with a document table as in the prior art disclosed in Patent Document 1, if a light guide is provided as in the prior art disclosed in Patent Document 2, the light emission direction in the light guide Therefore, the light irradiation area can be generally limited to the range of the document table, but there is a limit to the light irradiation area limitation by this light guide. Is inevitable.

  On the other hand, when the image reading surface on the document table is imaged by the imaging device via the mirror, the peripheral portion of the document table is prevented from entering the angle of view of the imaging device. When the mirror is provided as described above, the light reflected by the peripheral part of the document table is reflected twice by the mirror and incident on the image pickup device. Specifically, the light is reflected by the document table after being reflected by the mirror. In this case, a path that is reflected again and enters the imaging device is formed, and the peripheral portion of the document table may appear in the captured image. This reflection of the peripheral portion of the document table is desirably avoided because it may deteriorate the quality of the captured image and cause problems such as a decrease in accuracy in the detection process of the document area in the captured image.

  The present invention has been devised to solve such problems of the prior art, and its main purpose is to prevent the peripheral portion of the document table from appearing in the captured image. It is to provide a configured reading apparatus.

  A reading apparatus according to the present invention includes a transparent document table on which a document is placed, a document table support unit that supports the document table, and an illumination device that illuminates a reading surface of the document placed on the document table. An imaging device that images the reading surface of the document illuminated by the illumination device, a mirror that reflects light from the reading surface of the document and guides it to the imaging device, and the document table in the document table support section. And a light shielding plate that blocks light reflected from the peripheral portion and traveling in the direction of the mirror.

  According to the present invention, the light reflected in the peripheral part of the document table and traveling in the direction of the mirror is blocked by the light shielding plate, so that the light reflected in the peripheral part of the document table is reflected by the mirror and enters the imaging device. A route is not formed. For this reason, it is possible to prevent the peripheral portion of the document table from appearing in the captured image, and thus it is possible to avoid problems such as a decrease in accuracy in the detection process of the document area in the captured image. .

Sectional drawing of the principal part of the reader 1 which concerns on this embodiment. Perspective view of main part of reading device 1 Sectional view of the lighting device 5 Front view of illumination board 12 The front view which shows the state which attached the light guides 13a-13d and the spacers 14a-14d to the illumination board 12 Sectional view of the light guide 13b on the upper right side Sectional view of the light guide 13d on the lower right side Perspective view of spacers 14b and 14d Sectional drawing which shows the condition where the light from the reading surface 3a of the original document 3 injects into the imaging device 6 by a comparative example FIG. 9 is an explanatory diagram illustrating a situation in which the image of the reading surface 3a of the document 3 is reflected twice in the captured image in the comparative example illustrated in FIG. The principal part sectional view of reading device 1 which shows the situation where the light from reading surface 3a of original 3 enters into image pick-up device 6 by this embodiment. Sectional drawing which shows the comparative example which changed the arrangement position of the illuminating device 5 and the imaging device 6 Sectional drawing explaining the positional relationship of the illuminating device 5 with respect to the original stand 4 when a bright spot generate | occur | produces in a captured image in a US passport by a comparative example Sectional drawing of the principal part of the reader 1 explaining the positional relationship of the illumination device 5 with respect to the document table 4 according to the present embodiment. Explanatory drawing which shows the picked-up image of MRZ of US passport Cross-sectional view of the main part of the reading apparatus 1 for explaining the effect of the light shielding plate 32 Sectional drawing of the principal part of the reader 1 explaining the structure which prevents the reflection of the antenna substrate 52 Explanatory drawing which shows the situation where the reflection of the antenna board 52 occurred in the captured image The perspective view which turned over the upper wall part 51 of the housing 2, and was seen The perspective view which shows the modification of a light-shielding plate Explanatory drawing showing the illuminance distribution on the reading surface 3a of the document 3 Rear view showing the light diffusion part 61 formed on the incident surface 15 of the light guide 13b on the upper right side. Front view showing a light diffusion portion 62 formed on the exit surface 16 of the light guide 13d on the lower right side Explanatory drawing which shows the emission condition of the light in upper light guide 13a, 13b Explanatory drawing which shows the light emission condition in the lower light guides 13c and 13d Sectional drawing which shows the metal mold 65 for light guide body shaping | molding upper light guide 13a, 13b Sectional drawing which shows the metal mold | die 66 for light guide body shaping | molding lower light guides 13c and 13d Schematic top view showing light guides 13a to 13d and imaging device 6 Explanatory drawing which shows the situation where the high-intensity part occurred in the captured image Sectional drawing of the principal part of the reader 1 which shows the advancing condition of the light radiate | emitted from the end surface 17 of the light guides 13a-13d. A perspective view of the mirror box 73 in which the light guides 13a to 13d are arranged. The front view which looked at the principal part of mirror box 73 from the optical axis direction of imaging device 6 Side view of mirror box 73

  In order to solve the above-described problems, a first invention provides a transparent document table on which a document is placed, a document table support portion that supports the document table, and a document document placed on the document table. An illumination device that illuminates the reading surface, an imaging device that images the reading surface of the document illuminated by the illumination device, a mirror that reflects light from the reading surface of the document and guides it to the imaging device, and the document A light-shielding plate that shields light reflected from the peripheral portion of the document table in the table support portion and traveling in the direction of the mirror.

  According to this, since the light reflected in the peripheral portion of the document table and traveling in the direction of the mirror is blocked by the light shielding plate, the light reflected by the peripheral portion of the document table is reflected by the mirror and enters the imaging device. Not formed. For this reason, it is possible to prevent the peripheral portion of the document table from appearing in the captured image, and thus it is possible to avoid problems such as a decrease in accuracy in the detection process of the document area in the captured image. .

  According to a second aspect of the present invention, an antenna substrate for communicating with a communication device mounted on the document is provided on the document table support portion, and the light reflected by the antenna substrate and traveling in the direction of the mirror is transmitted. The light shielding plate is used to block the light.

  According to this, since the reflectance of light is increased by the resin layer formed on the surface of the antenna substrate, an image due to reflection appears in the captured image. However, if the light shielding plate is provided as described above, the antenna substrate Can be prevented.

  According to a third aspect of the present invention, the illumination device and the imaging device are disposed below one end side of the document table, and the mirror is disposed below the other end side of the document table, and a reflecting surface thereof is the document table. The light shielding plate is provided on the one end side of the document table so as to face both the image pickup apparatus and the document table.

  According to this, the illumination device and the imaging device are arranged below one end side of the document table, the mirror is arranged below the other end side of the document table, and the reflection surface of the mirror faces both the document table and the imaging device. Since the peripheral portion on one end side of the document table is reflected in the captured image when provided in a state inclined with respect to the document table, a peripheral portion of the document table is provided by providing a light shielding plate on one end side of the document table. It is possible to prevent the captured image from being reflected.

  According to a fourth aspect of the present invention, the light shielding plate is provided in a straight line so as to be along one edge of the rectangular document table.

  According to this, it is possible to prevent a portion that appears in the captured image relatively remarkably in the peripheral portion of the document table, that is, a portion located outside the edge portion on one end side of the document table from being reflected in the captured image. As a result, most of the image resulting from the reflection of the peripheral portion of the document table can be prevented from appearing in the captured image.

  According to a fifth aspect of the invention, the light shielding plate is provided in a U shape so as to be along three edge portions of the rectangular document table.

  According to this, when a portion located outside the edge portion on one end side of the document table and a portion located outside the edge portion of the document table on both sides are reflected in the captured image, the image by this reflection is displayed. Can be prevented from appearing in the captured image.

  According to a sixth aspect of the present invention, the light shielding plate is integrally formed in a manner of projecting downward in a rib shape on the upper wall portion of the housing constituting the document table support portion.

  According to this, since the light shielding plate is formed integrally with the housing, the number of parts and the number of assembly steps can be reduced. Further, since the light shielding plate protrudes in a rib shape, the rigidity of the housing against an external force acting when the original is pressed against the original table can be increased.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a main part of a reading apparatus 1 according to the present embodiment. The reading apparatus 1 includes a housing 2, a document table 4 on which a document 3 such as a passport or a license is placed with the reading surface 3a facing down, and a reading surface 3a of the document 3 placed on the document table 4. , An imaging device 6 that images the reading surface 3a of the document 3 illuminated by the illuminating device 5, and a mirror 7 that reflects light from the reading surface 3a of the document 3 and guides it to the imaging device 6. And a main substrate 8 on which components related to the control of the illumination device 5 and the imaging device 6 are mounted.

  The document table 4 is formed of a transparent glass plate, and is provided on the upper surface of the housing 2. A mirror 7 is disposed below the document table 4. The illumination device 5 and the imaging device 6 are disposed on the same side with respect to the mirror 7 obliquely below the document table 4. The illumination device 5 is disposed obliquely upward so as to face the document table 4. The imaging device 6 is disposed on the back side of the illumination device 5 in a state of facing the mirror 7 so as to face the mirror 7, passes through the opening portion 9 provided in the illumination device 5, and passes from the mirror 7. The light is guided to the imaging device 6.

  The mirror 7 is placed on the document table 4 with one end side of the document table 4 (the side on which the illumination device 5 and the imaging device 6 are disposed) facing down so that the reflecting surface 7 a faces both the document table 4 and the imaging device 6. It is provided in an inclined state. In particular, in the present embodiment, the mirror 7 is arranged such that the inclination angle α with respect to the direction along the document table 4 (horizontal direction) is 45 °, and the imaging device 6 has the optical axis substantially parallel to the document table 4. Are arranged as follows.

  In the reading apparatus 1 configured as described above, the light emitted from the illumination device 5 enters the document table 4 to illuminate the reading surface 3 a of the document 3 placed on the document table 4, thereby reading the document 3. Reflected light (diffused light) on the surface 3 a is reflected by the mirror 7 and enters the imaging device 6. In this way, the optical path that guides the reflected light from the reading surface 3 a of the document 3 to the imaging device 6 is bent by the mirror 7, whereby the size of the reading device 1 can be reduced.

  FIG. 2 is a perspective view of a main part of the reading device 1. FIG. 3 is a cross-sectional view of the lighting device 5.

  As shown in FIG. 3, the illumination device 5 includes an LED element (light source) 11, an illumination substrate 12 that holds the LED element 11, and a light guide 13 a that guides light emitted from the LED element 11 in a predetermined direction. To 13d (see FIG. 2) and spacers (intermediate supports) 14a to 14d (see FIG. 2) interposed between the light guides 13a to 13d and the illumination board 12. The light guides 13a to 13d are made of a light-transmissive resin material such as acrylic resin (PMMA). The spacers 14a to 14d are formed of a resin material such as polycarbonate resin and are colored black.

  As shown in FIG. 2, the light guides 13 a to 13 d have a long rod shape in one direction, and are arranged so that the longitudinal direction (X direction) is substantially parallel to the document table 4. The four light guides 13a to 13d are provided vertically and horizontally, and the upper two light guides 13a and 13b are formed symmetrically with respect to each other with an opening 21 described later therebetween, and the two lower guides Similarly, the light bodies 13c and 13d are formed in symmetrical shapes.

  An opening 21 is formed at the center of the illumination substrate 12, and light guides 13 a to 13 d are disposed on both the left and right sides of the opening 21. Due to the opening 21 of the illumination board 12 and the gap between the left light guides 13a and 13c and the right light guides 13b and 13d, the imaging device 6 disposed on the back side of the illumination board 12 An opening 9 for defining an optical path for guiding light from the mirror 7 is defined.

  As shown in FIG. 1, the illumination device 5 is provided obliquely upward so as to face the document table 4. In particular, in this embodiment, the illumination device 5 is in a direction along the document table 4 of the illumination substrate 12. Is arranged such that the inclination angle β with respect to is 48 °. The light guides 13 a to 13 d share the illumination area on the document table 4, and the upper light guides (first light guides) 13 a and 13 b near the document table 4 are responsible for the illumination area near the illumination device 5. The lower light guides (second light guides) 13 c and 13 d far from the document table 4 are in charge of the illumination area far from the illumination device 5. The left light guides 13a and 13c are generally responsible for the left illumination area, and the right light guides 13b and 13d are generally responsible for the right illumination area.

  Thus, in this embodiment, the inclination angle β (48 °) of the illumination device 5 (illumination substrate 12) with respect to the document table 4 and the inclination angle α (45 °) of the mirror 7 with respect to the document table 4 are made substantially equal. In the cross section including the illumination device 5, the document table 4, the mirror 7 and the imaging device 6, the mirror 7 and the illumination device 5 are arranged substantially symmetrically. Further, by arranging the illuminating device 5 and the imaging device 6 at positions close to each other, the illuminating device 5 and the imaging device 6, the document table 4, and the mirror 7 are arranged so as to be located on each side of the triangle. The Further, the light emitted from the illuminating device 5 is diffused (scattered) on the reading surface 3 a of the document 3 on the document table 4, and the diffused light is reflected by the mirror 7 and arranged on the back surface of the illumination substrate 12. Although incident on the device 6, the optical path of the light emitted from the lower light guides 13 c and 13 d located in front of the imaging device 6 intersects the optical path of the light incident on the imaging device 6 from the mirror 7. ing. With these configurations, the space can be used effectively and the apparatus size can be reduced.

  As shown in FIG. 3, the light guides 13 a to 13 d include an incident surface 15 on which light emitted from the LED element 11 is incident on the side facing the LED element 11, and on the side opposite to the incident surface 15. An exit surface 16 from which light incident from the entrance surface 15 exits is provided. The entrance surface 15 and the exit surface 16 extend in the longitudinal direction of the light guides 13a to 13d (see FIG. 2). The incident surface 15 is formed in a planar shape perpendicular to the optical axis of the LED element 11, but an optical path conversion unit such as a recess or a prism may be provided in a portion facing the LED element 11 (see FIG. 6). ).

  On the other hand, the emission surface 16 is formed such that a cross section cut along a plane orthogonal to the longitudinal direction of the light guides 13a to 13d forms an arc shape. In particular, in the present embodiment, the cross section of the emission surface 16 is formed by combining a plurality of arcs, and the radius of each of the plurality of arcs is configured to be relatively smaller when closer to the mirror 7 (Ra < Rb, Rc <Rd). Thereby, the light is largely refracted on the side opposite to the mirror 7 (the direction away from the mirror 7) at the portion of the emission surface 16 having a small radius so that the light does not go in the direction of the mirror 7. The emission angle of the light emitted from is generally limited to a predetermined angle range (regular emission angle ranges R1, R2) (see FIG. 1).

  FIG. 4 is a front view of the illumination board 12. FIG. 5 is a front view showing a state in which the light guides 13 a to 13 d and the spacers 14 a to 14 d are attached to the illumination board 12.

  As shown in FIG. 4, a plurality of LED elements 11 are arranged on the illumination board 12 along the longitudinal direction of the light guides 13 a to 13 d so as to cover the LED elements 11 constituting the upper LED element array. The upper light guides 13a and 13b are arranged (see FIG. 5), and the lower light guides 13c and 13d are arranged so as to cover the LED elements 11 constituting the lower LED element row (FIG. 5). reference).

  In particular, in this embodiment, as the LED element 11, a white LED element (white light source) 11wl that emits white light, an infrared LED element (infrared light source) 11ir that emits infrared light, and an ultraviolet LED element that emits ultraviolet light ( Three types of light sources (ultraviolet light source) 11 uv are provided. For example, an infrared LED element 11ir having a peak wavelength of 850 nm is used, and an ultraviolet LED element 11uv having, for example, a peak wavelength of 365 nm is used. Here, the white LED element 11wl, the infrared LED element 11ir, and the ultraviolet LED element 11uv are collectively referred to as the LED element 11 as appropriate.

  These LED elements 11 are selectively used according to the application, and the white LED element 11wl is turned on in a normal application for visual confirmation by an operator using a monitor. In the case of performing character recognition of a document in which characters are described on a background image using a passport or the like, the infrared LED element 11ir is turned on. Thereby, it is difficult to capture the background image, and the accuracy of character recognition can be improved. When acquiring an image drawn with fluorescent ink for preventing counterfeiting with a passport or the like, the ultraviolet LED element 11uv is turned on. In this way, by using infrared light or ultraviolet light in addition to normal white light, it is possible to improve the accuracy of passport and license authentication.

  The LED element 11 takes into consideration the light distribution characteristics of itself and the difference in refractive index between white light, infrared light and ultraviolet light, etc., so that an optimal light amount distribution can be obtained. The positions are shifted in the direction orthogonal to the longitudinal direction (Y direction). The LED elements 11 are arranged symmetrically about the center line CE.

  FIG. 6 is a cross-sectional view of the light guide 13b on the upper right side. Here, only the upper right light guide 13b is illustrated, but the upper left light guide 13a appears symmetrically. FIG. 7 is a cross-sectional view of the light guide 13d on the lower right side. Here, only the light guide 13d on the lower right side is illustrated, but the light guide 13c on the lower left side appears symmetrically with respect to this (with regard to the positional relationship of “up, down, left and right”, both in FIGS. 4 and 5). reference).

  As shown in FIGS. 6 and 7, prisms 23 and 25 are formed on the incident surface 15 of the light guides 13a to 13d, whereby the longitudinal direction of the light guides 13a to 13d (X in FIG. 2). The light amount distribution of the document table 4 with respect to (direction) can be optimized. In particular, in this embodiment, the left light guides 13a and 13c and the right light guides 13b and 13d are spaced apart from each other, so that the illuminance is high at the center of the document table 4 corresponding to the position of the gap. Although there is a risk of reduction, the light traveling direction is changed by the prisms 23 and 25 to increase the light directed toward the center of the document table 4, thereby preventing the illuminance at the center of the document table 4 from decreasing. be able to. In addition, about the shape of the prisms 23 and 25, you may aim at one layer of light scattering by making the opposing surface of the LED element 11 into a concave meniscus shape like one of the infrared LED elements 11ir of FIG. 6, for example.

  Some passports have characters, patterns, and the like drawn using OVI (Optically Variable Inks) having a characteristic that the color changes by changing the irradiation angle of light for the purpose of preventing forgery. By irradiating the image with white light and changing the irradiation angle, the authenticity of the passport can be determined. Therefore, in the present embodiment, as shown in FIG. 6 and FIG. 7, a light emission direction changing unit that changes the light emission direction to an obliquely inward direction at the outer end of each of the light guides 13 a to 13 d. 24 and 26 are formed. When the white LED element 11wl corresponding to the light emitting direction changing units 24 and 26 is turned on, the white LED element 11wl disposed in the middle portion in the longitudinal direction of the light guides 13a to 13d is turned on in a different direction. The reading surface 3a of the document 3 can be irradiated with light.

  FIG. 8 is a perspective view of the spacers 14b and 14d. FIG. 8A shows the upper right spacer 14b, and FIG. 8B shows the lower right spacer 14d. The upper left and lower left spacers 14a and 14c (not shown) are symmetrical with the upper right and lower right spacers 14b and 14d, respectively (the positional relationship between the above "upper and lower left and right" is as shown in FIG. , See FIG.

  The spacers 14a to 14d are for supporting each of the light guides 13a to 13d on the illumination substrate 12 with a predetermined gap between the spacers 14a to 14d, and one spacer is provided for each of the light guides 13a to 13d. (See FIG. 2). In the spacers 14a to 14d, an opening 31 through which the light emitted from the LED element 11 (see FIG. 3) enters the incident surface 15 of the light guides 13a to 13d penetrates the spacers 14a to 14d in the thickness direction. Has been established to do. The opening 31 has a tapered shape in which the opening size increases from the illumination substrate 12 toward the light guides 13a to 13d, thereby improving the light utilization efficiency.

  The LED element 11 is a chip-shaped surface-mount type, and is soldered onto the illumination board 12 on which a wiring pattern is formed, and is provided in a state of protruding from the main surface of the illumination board 12. For this reason, by providing the spacers 14a to 14d between the illumination board 12 and the light guides 13a to 13d, the LED element 11 mounted on the illumination board 12 does not interfere with the light guides 13a to 13d. The light guides 13a to 13d can be stably supported by the illumination substrate 12.

  The spacers 14a to 14d are integrally formed with a light shielding plate 32 that blocks light emitted from the light guides 13a to 13d outside the normal emission angle range. As shown in FIG. 2, the light shielding plate 32 is provided so as to be positioned on the side of the light guides 13 a to 13 d in a state of protruding in a direction substantially orthogonal to the illumination substrate 12. The function of the light shielding plate 32 will be described in detail later.

  The spacers 14a to 14d are formed of a resin material colored in black to suppress reflection. In particular, the spacers 14a to 14d protrude in the light emitting direction in order to suppress reflection of infrared light having high reflectance even in black. The portion (the light shielding plate 32) may be subjected to a reflection reduction process such as attaching a light absorbing sheet. In particular, infrared light can be effectively absorbed by the light absorbing sheet.

  Now, by integrating the light shielding plate 32 with the spacers 14a to 14d, it can be expected to reduce the manufacturing cost and the man-hours for attaching the light shielding plate 32. On the other hand, in order to provide the light shielding plate 32 with a light shielding function. The spacers 14a to 14d must be black. However, considering the light utilization efficiency, the light reflectance of the opening 31 should be increased. In order to achieve both of them, in the present embodiment, the opening 31 of the spacer is tapered so that the upper part is widened, and the wall surface of the tapered portion is processed smoothly so that the light component can be directly emitted even if the material is black. I try to take it out as much as possible.

  Next, a configuration for eliminating the problem that the image of the reading surface 3a of the document 3 appears twice in the captured image will be described.

  FIG. 9 is a cross-sectional view illustrating a situation in which light from the reading surface 3a of the document 3 enters the imaging device 6 according to a comparative example. FIG. 10 is an explanatory diagram showing a situation in which the image of the reading surface 3a of the document 3 is doubled in the captured image in the comparative example shown in FIG. In this comparative example, the mirror 7 is arranged so that the inclination angle α with respect to the direction along the document table 4 (horizontal direction) is 37 °. When the inclination angle α of the mirror 7 is small as described above, As will be described, an image by reflection different from the regular image of the reading surface 3a of the document 3 appears in the captured image.

  As shown in FIG. 9, the light incident on the reading surface 3a of the document 3 causes diffuse reflection on the reading surface 3a, and the reflected light diffuses in various directions. Here, when the inclination angle α of the mirror 7 is small, the reflected light from the reading surface 3 a of the document 3 is reflected once by the mirror 7 and enters the imaging device 6, and the reflection from the reading surface 3 a of the document 3. There is a path through which light is reflected twice by the mirror 7 and enters the imaging device 6.

  In the example shown in FIG. 9, as indicated by paths PA, PB, and PC, the reflected light at points A, B, and C is reflected once by the mirror 7 and enters the imaging device 6. Further, as indicated by paths PA ′ and PC ′, the reflected light at each of the points A and C is reflected by the mirror 7, then by the document table 4, and again by the mirror 7, and then by the imaging device 6. Is incident on. In the region on the reading surface 3a of the document 3 on the side of the point B from the point C, the light traveling in the direction reflected twice by the mirror 7 deviates from the mirror 7, and is reflected twice by the mirror 7 and applied to the imaging device 6. There is no incident path.

  When there is a path that is reflected once by the mirror 7 and enters the imaging device 6 and a path that is reflected twice by the mirror 7 and enters the imaging device 6, as shown in FIG. Shows a normal image 41 by a path reflected once by the mirror 7 and a reflected image 42 by a path reflected by the mirror 7 twice. Here, as shown in the figure, if the regular image 41 and the captured image 42 appear separately, erroneous detection of the document area in the captured image occurs. In addition, the reflected image may appear to overlap the regular image. In this case, the image on the reading surface 3a of the document 3 cannot be appropriately acquired, and an error occurs in, for example, passport authentication. .

  FIG. 11 is a cross-sectional view of the main part of the reading device 1 showing a state in which light from the reading surface 3a of the document 3 is incident on the imaging device 6 according to the present embodiment. In this embodiment, the mirror 7 is arranged so that the inclination angle α with respect to the direction along the document table 4 is 45 °, and the inclination angle α of the mirror 7 is larger than that of the comparative example shown in FIG. .

  Here, the light emitted from the point D is considered. The light emitted from this point D is reflected once by the mirror 7 and enters the imaging device 6 as indicated by the path PD, and a regular image appears in the captured image. On the other hand, as indicated by the path PD ', the light traveling in the direction reflected twice by the mirror 7 deviates from the mirror 7, so that a path that is reflected twice by the mirror 7 and enters the imaging device 6 is not possible. For this reason, the image by reflection does not appear in the captured image.

  In addition, the light emitted from the point E located outside the point D (the outer peripheral side of the document table 4) is reflected once by the mirror 7 and incident on the imaging device 6 as indicated by the path PE. A regular image appears at. Further, the light emitted from the point E is reflected twice by the mirror 7 and enters the imaging device 6 as indicated by a path PE ′. However, since this light deviates from the angle of view F of the imaging device 6, imaging is performed. The image due to reflection does not appear in the image.

  In this way, in the region inside the point D (center side of the document table 4), the light traveling in the direction reflected twice by the mirror 7 deviates from the mirror 7, and in the region outside the point D, by the mirror 7. The light traveling in the direction reflected twice deviates from the angle of view F of the imaging device 6, and in any case, no image due to reflection appears in the captured image.

  Since the image formation by the reflection shown in FIGS. 9 and 10 is caused by reflection on the document table 4, an AR (anti-reflective) coat is used to suppress the reflection on the document table 4. Although this AR coating is effective in white light, it is easily reflected back in infrared light, and thus has an adverse effect and cannot be employed.

  As described above, in the present embodiment, the mirror 7 is arranged so that the inclination angle α with respect to the direction along the document table 4 of the mirror 7 is increased, specifically, the inclination angle α is 45 °, and the captured image is displayed. Although the reading surface 3a of the document 3 is prevented from appearing twice, the image pickup device 6 is arranged right next to the mirror 7. However, when such a positional relationship is applied as it is to the configuration according to the comparative example shown in FIG. 9, there arises a problem that the imaging device 6 and the illumination device 5 interfere. For this reason, as shown below, it is necessary to change the arrangement positions of the illumination device 5 and the imaging device 6.

  FIG. 12 is a cross-sectional view illustrating a comparative example in which the arrangement positions of the illumination device 5 and the imaging device 6 are changed.

  As shown in FIG. 12A, when the illumination device 5 is disposed below the imaging device 6, the incident angle I of the light with respect to the document table 4 is too small, so that the light reflected by the document table 4 is reflected by the mirror 7 once. A path that is reflected and incident on the imaging device 6 is formed. On the other hand, as shown in FIG. 12B, when the illumination device 5 is disposed above the imaging device 6, the incident angle I of light with respect to the document table 4 is too large, so that the light reflected by the document table 4 is reflected by the mirror 7. The path that is reflected twice and enters the imaging device 6, specifically, the light reflected by the document table 4 is reflected by the mirror 7, is reflected by the document table 4, is reflected by the mirror again, and is reflected on the imaging device 6. An incident path is created. Since the light traveling along such a path becomes direct light due to specular reflection, the amount of light incident on the imaging device 6 is large, causing a problem that a high-luminance portion (out-of-white) occurs in the captured image.

  In addition, as illustrated in FIG. 12A, when the illumination device 5 is disposed below the imaging device 6, or as illustrated in FIG. 12C, the imaging device 6 is positioned below the illumination device 5. In addition, when both the imaging device 6 and the mirror 7 are moved downward, the height of the entire reading device 1 increases, and the usability of the reading device 1 that is used while being placed on a desk is deteriorated. Occurs.

  Therefore, in the present embodiment, as illustrated in FIG. 2, the imaging device 6 is disposed on the back side of the lighting device 5, the light guides 13 a to 13 d are spaced apart from each other, and An opening 21 is formed at the center, and the opening 9 defined by the opening 21 of the illumination substrate 12 and the gaps between the left and right light guides 13a to 13d is used to capture the light from the mirror 7 and the imaging device. The optical path leading to 6 passes. Thereby, the illuminating device 5 can be arrange | positioned in an optimal position, without interfering with the imaging device 6. FIG.

  Next, a description will be given of a configuration that eliminates a problem that a bright spot is generated in a captured image in an original document laminated with a transparent film, particularly a US passport.

  FIG. 13 is a cross-sectional view for explaining the positional relationship of the illumination device 5 with respect to the document table 4 when a bright spot occurs in a captured image in the US passport according to a comparative example. FIG. 14 is a cross-sectional view of the main part of the reading device 1 for explaining the positional relationship of the illumination device 5 with respect to the document table 4 according to the present embodiment. FIG. 15 is an explanatory diagram showing a captured image of MRZ (Machine Readable Zone) in the US passport. FIG. 15A shows a situation where a bright spot is generated in the captured image. The situation where the bright spot of the captured image has disappeared is shown.

  As shown in FIG. 13, a stopper portion 45 for positioning the document 3 is provided on the side edge of the document table 4 on the side close to the illumination device 5, and the end of the document 3 is placed on the stopper portion 45. It is hit. Here, when the document 3 is an American passport, the image is captured in a state where the end of the page on which the MRZ exists is abutted against the stopper portion 45. In this case, as illustrated in FIG. A bright spot is generated at the MRZ position located at the end of the page. This MRZ has a character string that is subjected to OCR (Optical Character Recognition). If a bright spot is generated here, the accuracy of character recognition in the OCR is lowered, and an erroneous determination occurs in the passport authentication determination.

  In the comparative example shown in FIG. 13, the illumination device 5 is arranged to be shifted downward as compared with the embodiment shown in FIG. 14, and the incident angle I of light with respect to the reading surface 3 a of the document 3 is small. At the position of the end of the document 3 located on the side close to the illumination device 5, the illumination angle (the incident angle I, that is, the angle formed between the incident direction of light with respect to the reading surface 3a and the reading surface 3a) G is 61 °. Bright spots occur in the range of ˜57 °. The bright spot generation range is a range of 10 mm from the end of the document 3.

  This is considered to be due to the fact that the light that is specularly reflected by the surface of the laminate layer of the original 3 is reflected by the mirror 7 and enters the imaging device 6 when the incident angle I of the light with respect to the reading surface 3a of the original 3 is small. In particular, since light is applied obliquely from below, the incident angle I of light with respect to the reading surface 3a of the document 3 is small, that is, the illumination angle G is large at the end of the document 3 on the side close to the illumination device 5. , Bright spots occur.

  On the other hand, in the present embodiment shown in FIG. 14, the illumination device 5 is arranged to be shifted upward as compared with the comparative example shown in FIG. 13, and the incident angle of light with respect to the reading surface 3 a of the document 3. I is large, that is, the illumination angle G is small. In particular, the illumination angle G should be 55 ° or less, particularly preferably 50 ° or less at the end portion on the side close to the illumination device 5 where the illumination angle G is the largest. Here, when the document 3 is an American passport, the illumination angle G is preferably set to 50 ° to 52 ° in a portion (width of 7 mm to 8 mm) where the MRZ where character recognition is performed exists.

  When the illumination device 5 is arranged so that the illumination angle (the angle of incidence of the incident angle I, that is, the angle between the incident direction of light with respect to the reading surface 3a and the reading surface 3a) G is reduced in this way, In particular, in the US passport, as shown in FIG. 15B, it is possible to suppress the occurrence of bright spots in the region on one end side close to the illumination device 5, particularly in the MRZ position.

  Next, a configuration that eliminates a problem that a high-luminance portion is generated in a captured image due to light emitted from the light guides 13a to 13d outside the normal emission angle range, that is, the light shielding plate 32 illustrated in FIG. 8 will be described. .

  FIG. 16 is a cross-sectional view of the main part of the reading device 1 for explaining the effect of the light shielding plate 32. The light emitted from the LED element 11 (see FIG. 4) and incident on the light guides 13a to 13d passes through the inside of the light guides 13a to 13d, mainly in the normal emission angle ranges R1 and R2, and the emission surface 16. Is emitted from the light guides 13a to 13d in a direction deviating from the normal emission angle ranges R1 and R2 due to irregular reflection of light in the light guides 13a to 13d, minute scratches on the emission surface 16, and the like. Light may be generated. In particular, there is a limit to the processing accuracy of the light guide made of resin, and such emitted light is generated in an unpredictable direction in design.

  Here, if the light shielding plate 32 is not provided, light deviating from the normal emission angle ranges R1 and R2 is directly incident on the mirror 7 and is reflected here to become stray light. The stray light is reflected by the document table 4 and then reflected again by the mirror 7 and enters the imaging device 6. When stray light is incident on the imaging device 6 in this way, the LED element 11 is directly captured as a result, and a portion where the luminance is partially increased appears in the captured image. Although this stray light component is very small according to simulation, etc., it is direct light without scattering reflection, so it is a large amount of light for each photodiode constituting the image sensor, and the accumulated charge of the pixel irradiated with stray light Becomes saturated and becomes a high-luminance portion on the image. This high-intensity part degrades the quality of the captured image, and may cause problems such as a decrease in accuracy in the document area detection process or character recognition process in the captured image.

  On the other hand, in this embodiment, since the light-shielding plate 32 is disposed, out of the light emitted from the light guides 13a to 13d out of the normal emission angle ranges R1 and R2, it is in the direction of the mirror 7. The traveling light is blocked by the light blocking plate 32. For this reason, the stray light generated by the light emitted from the light guides 13a to 13d being reflected by the mirror 7 as it is can be reduced. As a result, the stray light is incident on the imaging device 6 and appears in the captured image. Generation of a luminance portion can be suppressed.

  The light shielding plate 32 is provided so as to extend in a direction substantially along the light emission direction from the light guides 13a to 13d. The light shielding plate 32 has a length L1, L2 in the emission direction, that is, an illumination substrate. When the projection height from 12 is increased, the light paths in the normal emission angle ranges R1 and R2 of the light emitted from the light guides 13a to 13d are blocked by the light shielding plate 32, so the normal emission angle ranges R1 and R2 It is necessary to set the lengths L1 and L2 of the light shielding plate 32 so as not to block the inner optical path.

  In particular, since the light shielding plate 32 corresponding to the upper light guides 13a and 13b is located between the upper light guides 13a and 13b and the lower light guides 13c and 13d, the normal emission angle range of the both It is necessary to set the length L1 of the light shielding plate 32 so as not to block both the optical paths in R1 and R2. The normal emission angle ranges R1 and R2 in each of the light guides 13a to 13d are determined by the position of the LED element 11 having a known light quantity distribution and the radius of an arc that defines the cross-sectional shape of the emission surface 16.

  Further, when the lengths L1 and L2 in the emission direction of the light shielding plate 32 are increased, the light path that guides the reflected light from the reading surface 3a of the document 3 to the mirror 7 is blocked by the light shielding plate 32, and therefore from the reading surface 3a of the document 3. It is necessary to set the lengths L1 and L2 of the light shielding plate 32 so as not to block the optical path of the reflected light.

  Further, the lengths L1 and L2 of the light shielding plate 32 necessary to reliably block the light traveling from the light guides 13a to 13d to the mirror 7 depend on the inclination angle β of the illumination board 12, and the inclination angle of the illumination board 12 When β is increased, it is necessary to increase the lengths L1 and L2 of the light shielding plate 32. Conversely, when the inclination angle β of the illumination substrate 12 is decreased, the lengths L1 and L2 of the light shielding plate 32 may be decreased. For this reason, in order to reduce the lengths L1 and L2 of the light shielding plate 32, it is desirable to reduce the inclination angle β of the illumination substrate 12.

  On the other hand, when the inclination angle β of the illumination substrate 12 is decreased, the incident angle with respect to the document table 4 is decreased, so that the illuminance unevenness on the reading surface 3a of the document 3 becomes remarkable, and the reflected light from the document table 4 is mirrored 7, and the light reflected by the mirror 7 enters the imaging device 6, thereby generating a high-luminance portion in the captured image. For this reason, it is desirable to increase the inclination angle β of the illumination board 12 in order to suppress the occurrence of uneven illuminance and high-luminance portions in the captured image.

  Therefore, the light path within the normal emission angle ranges R1 and R2 of the light emitted from the light guides 13a to 13d and the light path of the reflected light from the reading surface 3a of the document 3 are not blocked by the light shielding plate 32. In addition, the lengths L1 and L2 of the light shielding plate 32 are set as small as possible within a range in which unevenness in illuminance and generation of high-luminance portions in the captured image can be sufficiently suppressed. Therefore, it is necessary to set the inclination angle β of the illumination substrate 12 (the arrangement angle of the illumination device 5). In this embodiment, the angle β of the illumination substrate 12 is set to 48 ° from this point of view. Yes.

  Since the upper light guides 13a and 13b have a large regular emission angle range R1, a light shield corresponding to the upper light guides 13a and 13b is provided so as not to block the optical path within the regular emission angle range R1. Since the plate 32 is arranged away from the light guides 13a and 13b, the length of the light shielding plate 32 is large, while the lower light guides 13c and 13d have a small normal emission angle range R2, Since the light shielding plate 32 can be brought close to the light guides 13c and 13d, the length of the light shielding plate 32 is reduced.

  Next, a configuration for solving the problem that the antenna substrate arranged around the document table 4 appears in the captured image will be described.

  FIG. 17 is a cross-sectional view of a main part of the reading apparatus 1 for explaining a structure for preventing the antenna substrate 52 from being reflected. FIG. 18 is an explanatory diagram illustrating a situation in which the antenna substrate 52 is reflected in the captured image. FIG. 19 is a perspective view in which the upper wall portion 51 of the housing 2 is viewed upside down.

  The reading device 1 of the present embodiment images a passport or a license as a document as described above and determines its authenticity. For example, a license or a passport on which an IC chip (communication device) is mounted is used. By verifying whether or not the character information acquired by performing the OCR process on the captured image matches the information stored in the IC chip, it is possible to determine the authenticity with higher accuracy.

  For this reason, as shown in FIG. 17, an antenna substrate for communicating with an IC chip built in a document such as a passport is provided on the upper wall portion 51 of the housing 2 where the document table 4 of the reading device 1 is disposed. 52 is disposed. The antenna substrate 52 is disposed on the upper wall 51 in a U-shape along the outer periphery of the rectangular document table 4 (see FIG. 19). The loop antenna is configured as a whole.

  For example, a glass epoxy substrate is used as the antenna substrate 52, but the light reflectance is increased by the wiring pattern and the resin layer formed on the surface. For this reason, when light emitted from the light guides 13a to 13d in a direction deviating from the normal emission angle ranges R1 and R2 due to scratches on the output surface 16 of the light guide is incident on the antenna substrate 52, it diffuses here. When reflection occurs and light is radiated in multiple directions and a part of this light enters the imaging device 6 as direct light, the antenna substrate 52 is reflected in the captured image, that is, in the captured image as shown in FIG. In addition to the image 57 of the reading surface 3a of the document 3, an image 58 of the antenna substrate 52 appears.

  That is, as shown in FIG. 17, the light reflected by the peripheral part of the document table 4 is reflected twice by the mirror 7 and enters the imaging device 6. Specifically, the mirror 7, the document table 4, and the mirror 7 are reflected. A path P that is sequentially reflected in this order and enters the imaging device 6 is formed. As a result, as shown in FIG. 18, a portion of the antenna substrate 52 located on one end side of the document table 4 (the side where the illumination device 5 and the imaging device 6 are arranged) is reflected in the captured image. This reflection of the antenna substrate 52 may deteriorate the quality of the captured image and cause problems such as a decrease in accuracy in the detection process of the document area in the captured image.

  Therefore, in the present embodiment, a light shielding plate 53 is provided that blocks light reflected from the peripheral portion of the document table 4 and traveling toward the mirror 7. The light shielding plate 53 is provided on one end side of the document table 4, in other words, on the mirror 7 side of the antenna substrate 52 in a manner extending along the antenna substrate 52. As a result, of the light reflected from the antenna substrate 52, the light traveling in the direction of the mirror 7 is blocked by the light blocking plate 53. Therefore, the reflected light from the antenna substrate 52 is reflected by the mirror 7 and the path P for entering the imaging device 6 is not formed, and the antenna substrate 52 can be prevented from being reflected in the captured image.

  The light shielding plate 53 is integrally formed on the upper wall portion (original plate support portion) 51 of the housing 2 so as to protrude downward in a rib shape. As a result, the number of parts and the number of assembling steps can be reduced, and the rigidity of the housing 2 against the external force acting when the document 3 is pressed against the document table 4 can be increased by the light shielding plate 53 protruding in a rib shape. it can.

  As shown in FIG. 19, the light shielding plate 53 is provided straight along one edge 4 a on one end side of the four edges 4 a to 4 d of the rectangular document table 4. In this way, the portion of the peripheral portion of the document table 4 that is relatively remarkably reflected in the captured image, that is, the antenna located outside the edge portion 4a on one end side of the document table 4 as shown in FIG. It is possible to prevent the portion 52a of the substrate 52 from appearing in the captured image, thereby preventing most of the image resulting from the reflection of the antenna substrate 52 from appearing in the captured image.

  FIG. 20 is a perspective view showing a modification of the light shielding plate. Here, the light shielding plate 56 is provided in a U shape so as to follow the three edge portions 4a, 4b, and 4c of the rectangular document table. In this way, as shown in FIG. 18, the edge portions 4b, 4c of the document table 4 on both sides of the antenna substrate 52 are provided along with the portion 52a of the antenna substrate 52 located outside the edge portion 4a on one end side of the document table 4. When the portions 52b and 52c of the antenna substrate 52 located outside the image are reflected in the captured image, it is possible to prevent all the images due to the reflection from appearing in the captured image.

  Next, a configuration for reducing illuminance unevenness on the reading surface 3a of the document 3 will be described.

  FIG. 21 is an explanatory diagram showing the illuminance distribution on the reading surface 3a of the document 3. FIG. 21A shows the case where the illuminance unevenness countermeasure is not taken, and FIG. The cases are shown respectively. This is an image of the shading sheet placed on the document table 4 with the white LED element 11wl turned on, and as shown in FIG. Regions with relatively low illuminance appear at the center and the bottom in the vertical direction.

  As in the comparative example shown in FIG. 9, when the inclination angle β of the illumination substrate 12 of the illumination device 5 is large (β = 60 °), the incident angle with respect to the document table 4 increases, that is, the incidence of light on the document table 4. Since the angle formed by the direction and the document table 4 is small, unevenness in illuminance on the reading surface 3a of the document 3 is unlikely to occur. However, if the inclination angle β of the illumination board 12 is decreased as in this embodiment (β = 48 °), since the incident angle with respect to the document table 4 becomes small, as shown in FIG. 21A, unevenness in illuminance on the reading surface 3a of the document 3 is likely to occur. This uneven illuminance on the reading surface 3a of the document 3 may cause problems such as a decrease in the quality of the captured image and a decrease in the accuracy of passport authentication.

  Therefore, as described below, in the present embodiment, a configuration for diffusing light is added to the light guides 13a to 13d to reduce illuminance unevenness on the reading surface 3a of the document 3.

  FIG. 22 is a rear view showing the light diffusing portion 61 formed on the incident surface 15 of the light guide 13b on the upper right side. Here, only the upper right light guide 13b is illustrated, but the upper left light guide 13a appears symmetrically. FIG. 23 is a front view showing the light diffusion portion 62 formed on the emission surface 16 of the light guide 13d on the lower right side. Here, only the light guide 13d on the lower right side is illustrated, but the light guide 13c on the lower left side appears symmetrically with respect to this (with regard to the positional relationship of “up, down, left and right”, both in FIGS. 4 and 5). reference).

  FIG. 24 is an explanatory diagram showing the light emission status of the upper light guides 13a and 13b. FIG. 24A shows the case where the light diffusing unit 61 is not provided, and FIG. Each case is shown. FIG. 25 is an explanatory diagram showing a light emission state in the lower light guides 13c and 13d. FIG. 25A shows the case where the light diffusing unit 62 is not provided, and FIG. 25B shows the light diffusing unit 62. Each case is indicated.

  As shown in FIG. 22, on the incident surface 15 of the upper light guides 13a and 13b, a rough light diffusing portion 61 for diffusing light is formed. The light diffusing portion 61 is partially formed at a position facing a part of the LED elements 11, specifically, a white LED element 11wl that emits white light and an infrared LED element 11ir that emits infrared light. Is not formed at a position facing the ultraviolet LED element 11uv that emits ultraviolet light.

  Therefore, in the upper light guides 13a and 13b, as shown in FIG. 24B, when the light emitted from the white LED element 11wl and the infrared LED element 11ir is incident on the incident surface 15, the light diffusion unit 61 Since it is diffused, it is possible to increase the amount of light in the end region of the normal emission angle range R1, thereby increasing the illuminance in the end region of the illumination region that the upper light guides 13a and 13b are responsible for. it can. Here, since the light diffusion portion is not formed on the emission surface 16, the light emission direction is controlled to some extent by the arcuate cross-sectional shape of the emission surface 16.

  As shown in FIG. 23, a rough light diffusing portion 62 for diffusing light is also formed on the emission surface 16 of the lower light guides 13c and 13d. The light diffusion portion 62 is formed over the entire emission surface 16.

  For this reason, in the lower light guides 13c and 13d, as shown in FIG. 25B, when the light emitted from the LED element 11 reaches the emission surface 16 through the light guides 13c and 13d. Since the light is diffused by the light diffusing unit 62, the amount of light in the end region of the normal emission angle range R2 can be increased, and thereby, in the end region of the illumination region handled by the lower light guides 13c and 13d. The illuminance can be increased. Here, since the light diffusion portion 62 is formed on the emission surface 16 having an arcuate cross-sectional shape, the light emission direction is controlled to be slightly diffused.

  As shown in FIG. 21A, the illuminance at the end of the illumination area that the upper light guides 13a and 13b and the lower light guides 13c and 13d are in charge of can be increased in this way. Furthermore, it is possible to increase the illuminance of the area where the illuminance appearing at the center and the lower part in the vertical direction on the reading surface 3a of the document 3 is relatively low. As a result, as shown in FIG. Irradiance unevenness on the surface 3a can be reduced.

  In particular, in the present embodiment, in the upper light guides 13a and 13b, the depth of the unevenness of the light diffusion portion 61 on the incident surface 15 is relatively increased to increase the degree of diffusion. As a result, the amount of light in the end region of the normal emission angle range R1 can be increased (see FIG. 24), and uneven illuminance on the reading surface 3a of the document 3 can be reduced. Thus, it is conceivable that the light emitted from the light guides 13a and 13b increases and stray light from the mirror 7 is remarkably generated. However, there is a light shielding plate 32 on the mirror 7 side of the upper light guides 13a and 13b (see FIG. 1), and the upper light guides 13a and 13b are away from the mirror 7, so that the normal emission angle is obtained. Light outside the range is difficult to enter the mirror 7. For this reason, there is no problem even if light deviating from the normal emission angle range increases due to strong light diffusion in the light diffusion portion 61.

  On the other hand, since the lower light guides 13c and 13d are close to the mirror 7, it is desirable to reduce the light traveling in the direction of the mirror 7 as much as possible. Therefore, in the lower light guides 13c and 13d, the unevenness depth of the light diffusing portion 62 on the emission surface 16 is made smaller than that of the light diffusing portion 61 on the incident surface 15, thereby reducing the degree of diffusion. ing.

  In the present embodiment, in the upper light guides 13a and 13b, the light diffusion portion 61 is selectively formed at positions corresponding to the white LED element 11wl and the infrared LED element 11ir on the incident surface 15, and the ultraviolet LED element 11uv. The light diffusion part 61 is not formed at a position corresponding to. This is because ultraviolet light is used for the purpose of emitting fluorescent ink on a manuscript, and the light emitted from the fluorescent ink is not easily affected by unevenness in the illuminance of the ultraviolet light itself, so that it is not particularly necessary to diffuse ultraviolet light. In addition, since the output of the ultraviolet LED element 11uv is low, it is not desirable that the light diffusion unit 61 diffuses the ultraviolet light to reduce the amount of light.

  On the other hand, in the lower light guides 13c and 13d, since the light diffusing portion 62 is formed on the entire emission surface 16, unlike the light diffusing portion 61 on the incident surface 15, the ultraviolet LED element 11uv emits. Although the ultraviolet light is also diffused, the light diffusion portion 62 of the emission surface 16 reduces the depth of the unevenness to weaken the degree of diffusion, so the decrease in the amount of light due to diffusion is small. In addition, since the lower light guides 13c and 13d have a narrower normal emission angle range than the upper light guides 13a and 13b (see FIG. 1), the lower light guides on the reading surface 3a of the document 3 are guided. Since uneven illuminance is relatively likely to appear in the illumination areas of the light bodies 13c and 13d, a light diffusion portion 62 is formed over the entire emission surface 16 so that ultraviolet light is diffused together with white light and infrared light. ing.

  As described above, in the present embodiment, the cross-sectional shape of the exit surface 16 of the light guides 13a to 13d is formed so that a plurality of arcs having different radii are connected, and the cross-sectional shape of the light emitted from the light guides 13a to 13d The overall directivity is defined, and on the other hand, the incident surface 15 or the exit surface 16 of the light guides 13a to 13d is roughened (smoothness is lost), so that the light guides 13a to 13d have appropriate light diffusibility. It is granted. Thereby, from the viewpoint of controlling the light intensity distribution, the light guides 13a to 13d of the reading apparatus according to the present embodiment have a light amount peak in the range of R1 and R2 depending on the cross-sectional shape of the light guide. The light diffusion portions 61 and 62 reduce the peak value and broaden the light intensity distribution (increase the half-value width). That is, the illumination device 5 of the present embodiment has the seemingly contradictory characteristics of light directivity and diffusivity.

  FIG. 26 is a cross-sectional view showing a light guide molding die 65 for molding the upper light guides 13a and 13b. FIG. 27 is a cross-sectional view showing a light guide molding die 66 for molding the lower light guides 13c and 13d.

  The light diffusion portions 61 of the upper light guides 13a and 13b and the light diffusion portions 62 of the lower light guides 13c and 13d can also be formed by directly blasting the light guides 13a to 13d. However, as shown in FIGS. 26 and 27, the light guides 13a to 13d can be formed by blasting the molds 65 and 66, thereby reducing the number of manufacturing steps and appropriately. The light guides 13a to 13d having the light diffusing portions 61 and 62 having various characteristics can be manufactured at low cost.

  In the molds 65 and 66, the parts 67 and 68 corresponding to the light diffusion portions 61 and 62 of the light guides 13a to 13d are blasted. As this blasting process, only the sandblasting process may be performed, but in addition to the sandblasting process, an alumina blasting process may be performed. The alumina blasting is performed after the sandblasting. In the sand blasting process, a sand abrasive having a relatively large particle size (S20 to S30) may be used. In the alumina blast treatment, an alumina abrasive having a medium particle size (A20 to A220) may be used.

  The dies 65 and 66 are made of, for example, die steel obtained by adding molybdenum, tungsten or the like to an alloy based on iron, carbon, or chromium. Since these are generally high in hardness, for example, sand blasting or alumina blasting is used. In the processing, there may be a case where unevenness having a sufficient depth cannot be formed in the light diffusion portions 61 and 62 of the light guides 13a to 13d that are the finished products. In particular, in the light diffusing portion 61 on the incident surface 15 of the upper light guides 13a and 13b, a surface processing method capable of sufficiently ensuring the depth of the unevenness is necessary in order to increase the depth of the unevenness as described above. become.

  In view of this, in a portion 67 corresponding to the light diffusing portion 61 of the incident surface 15 in the mold 65, it is preferable to perform blasting after first performing engraving with a engraving tool by hand. In this case, as the blasting process, only the sandblasting process (for example, S100) may be performed, but in addition to the sandblasting process, an alumina blasting process (for example, A220) may be performed.

  When engraving is performed in this manner, a relatively deep engraving can be formed in the surface processing portion of the mold 65, and in addition to this, a sand blasting process is performed to relatively shallow the surface of the deep engraving by engraving. An engraving is formed. Further, when alumina blasting is performed, a shallower engraving can be formed on the surface of the shallow engraving by sandblasting. For this reason, the diffusibility of light can be improved.

  Next, a configuration for solving the problem that a high-luminance portion appears in a captured image due to light emitted from the end faces in the longitudinal direction of the light guides 13a to 13d will be described.

  FIG. 28 is a schematic top view showing the light guides 13 a to 13 d and the imaging device 6. FIG. 29 is an explanatory diagram illustrating a situation where a high-luminance portion has occurred in a captured image. FIG. 30 is a cross-sectional view of the main part of the reading device 1 showing the progress of light emitted from the end faces 17 of the light guides 13a to 13d.

  As shown in FIG. 3, the light emitted from the LED element 11 and incident on the light guides 13 a to 13 d is emitted mainly from the emission surface 16 through the light guides 13 a to 13 d. As shown in FIG. 28, due to the directivity characteristics of the emitted light of itself, irregular reflection of light in the light guides 13a to 13d, and the like, the light guides 13a to 13d are slightly from the end face 17 on the imaging device 6 side in the longitudinal direction. It is emitted.

  When the light emitted from the end faces 17 of the light guides 13a to 13d becomes stray light and enters the imaging device 6, a high-luminance portion 71 appears in the captured image as shown in FIG. The high-luminance part in this captured image is what the end surfaces 17 of the light guides 13a to 13d appear to shine. As shown in FIG. 30, the light emitted from the inner end face 17 of the light guides 13 a to 13 d is reflected in the order of the mirror 7, the document table 4, and the mirror 7, and is directly reflected by specular reflection. This occurs because the light enters the imaging device 6.

  The light emitted from the outer end face 18 of the light guides 13a to 13d does not travel in the direction of the mirror 7 or the document table 4, and is reflected by the mirror 7 or the document table 4 to be incident on the imaging device 6. There is no route formed.

  In the present embodiment, in the present embodiment, the light emitted from the end face 17 of the light guides 13a to 13d is emitted from the inner end face 17 of the light guides 13a to 13d. A light shielding plate 72 is provided to block the light to be emitted.

  FIG. 31 is a perspective view of the mirror box 73 in which the light guides 13a to 13d are arranged. FIG. 32 is a front view of the main part of the mirror box 73 as seen from the optical axis direction of the imaging device 6. FIG. 33 is a side view of the mirror box 73.

  As shown in FIGS. 31 and 32, the light shielding plate 72 is disposed symmetrically on both sides of the optical path of the imaging device 6, and the inner end face 17 close to the imaging device 6 in the light guides 13 a to 13 d. It is provided to cover. The light shielding plate 72 is formed of a resin material colored in black integrally with a mirror box (dark box) 73. Thus, since the light shielding plate 72 is integrally formed with the mirror box 73, the light shielding plate 72 is stably supported, and the number of parts and the number of assembly steps can be reduced.

  The mirror box 73 blocks outside light. As shown in FIG. 33, the mirror box 73 holds the mirror holding unit 74 that holds the mirror 7, the lighting device holding unit 75 that holds the lighting device 5, and the imaging device 6. And an optical path that connects the illumination device 5, the document table 4 and the imaging device 6 to each other. An opening 77 into which the illumination device 5 is fitted is formed in the illumination device holding part 75, and the illumination device 5 is assembled from the outer surface side of the mirror box 73.

  As shown in FIG. 28, the portion 72a of the light shielding plate 72 close to the imaging device 6 is formed to be parallel to the optical axis OA of the imaging device 6, but the portion 72b away from the imaging device 6 is In a state in which the distance between the left and right light shielding plates 72 is inclined with respect to the optical axis OA of the imaging device 6 so as to gradually increase toward the mirror 7 so as not to block the optical path within the angle of view F of the imaging device 6. It is formed with.

  When the light shielding plate 72 is provided in this manner, stray light due to light emitted from the end faces 17 of the light guides 13a to 13d can be reduced, thereby suppressing generation of a high-luminance portion that appears in the captured image due to stray light. be able to.

  In addition, in this embodiment, as shown in FIG. 4, it has three types of light sources (white LED element 11wl, infrared LED element 11ir, ultraviolet LED element 11uv) which each emit white light, infrared light, and ultraviolet light. Although the present invention is configured, the present invention is not limited to this, and any one or two of the above three types of light sources, or a configuration having other types of light sources is also possible.

  The reading device according to the present invention has an effect of preventing the peripheral portion of the document table from appearing in the captured image, places the document on a transparent document table, and illuminates the reading surface of the document. It is useful as a reading device that illuminates with an image and captures an image of a document.

DESCRIPTION OF SYMBOLS 1 Reading apparatus 2 Housing 3 Original, 3a Reading surface 4 Original stand, 4a-4d Edge part 5 Illuminating device 6 Imaging device 7 Mirror, 7a Reflecting surface 11 LED element (light source)
11wl white LED element (white light source)
11 ir infrared LED element (infrared light source)
11uv UV LED element (UV light source)
12 Illumination boards 13a and 13b Light guide (first light guide)
13c, 13d Light guide (second light guide)
15 entrance surface 16 exit surface 51 upper wall portion (original table support portion)
52 Antenna board 53 Shading plate

Claims (6)

A transparent platen on which the document is placed;
A document table support section for supporting the document table;
An illumination device that illuminates a reading surface of the document placed on the document table;
An imaging device for imaging the reading surface of the document illuminated by the illumination device;
A mirror that reflects light from the reading surface of the document and guides it to the imaging device;
A reading apparatus comprising: a light shielding plate that blocks light that is reflected by a peripheral portion of the document table in the document table support portion and travels in the direction of the mirror.   An antenna substrate for communicating with a communication device mounted on the document is provided on the document table support portion, and the light reflected by the antenna substrate and traveling in the direction of the mirror is blocked by the light shielding plate. The reading apparatus according to claim 1. The illumination device and the imaging device are disposed below one end side of the document table,
The mirror is provided in an inclined state with respect to the document table so that a reflection surface faces both the document table and the imaging device below the other end side of the document table.
The reading apparatus according to claim 1, wherein the light shielding plate is provided on the one end side of the document table.   The reading apparatus according to claim 3, wherein the light shielding plate is provided in a straight line so as to be along one side edge portion of the original plate having a rectangular shape.   The reading apparatus according to claim 3, wherein the light shielding plate is provided in a U-shape so as to follow three edge portions of the rectangular document table.   6. The light shielding plate according to claim 1, wherein the light shielding plate is integrally formed in a form protruding downward in a rib shape on an upper wall portion of the housing constituting the document table support portion. The reading device described.