Reading device

The reading device of the present disclosure includes a housing, a first irradiation part, an imaging device, and a first diffusion part. The housing has an opening in an upper portion with a transparent reading window member. The first irradiation part emits an infrared light. The imaging device is disposed on a bottom portion such that an optical axis is directed to a reading window member. The first diffusion part is disposed on a left side wall connecting the upper and bottom portions. The first diffusion part diffuses the infrared light. The first diffusion part is made up of a light-transmitting first diffusion plate and a light-transmitting second diffusion plate. The first diffusion plate is disposed on the bottom surface side and inclined toward the upper portion. The second diffusion plate is disposed on the upper surface side and inclined toward the bottom portion.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a reading device imaging and reading a reading object.

2. Description of Related Art

JP 4473933 B1 discloses a reading device including a mounting surface on which a surface to be read of a reading object such as a passport is placed, an illumination light source including an infrared light source or a visible light source illuminating the surface to be read, an imaging part imaging the surface to be read, and a mirror changing an optical path from the surface to be read and focusing a light on the imaging part. The illumination light source is locally disposed close to the mounting surface, so that the reading device acquires an image with less illumination unevenness.

SUMMARY

The present disclosure provides a reading device reducing illumination unevenness to improve reading accuracy.

The reading device of the present disclosure includes a housing, a first irradiation part, an imaging device, and a first diffusion part. The housing has an opening in an upper portion with a transparent reading window member disposed therein. The first irradiation part emits an infrared light. The imaging device is disposed on a bottom portion facing the upper portion inside the housing such that an optical axis is directed to a reading window member. The first diffusion part is disposed on a left side wall connecting the upper portion and the bottom portion inside the housing. The first diffusion part diffuses the infrared light from the first irradiation part. The first diffusion part is made up of a light-transmitting first diffusion plate and a light-transmitting second diffusion plate. The first diffusion plate is disposed on the bottom surface side of the left side wall and inclined toward the upper portion. The second diffusion plate is disposed on the upper surface side of the left side wall and inclined toward the bottom portion.

The present disclosure can provide the reading device reducing illumination unevenness to improve reading accuracy.

DETAILED EMBODIMENTS

Embodiments will now be described in detail with reference to the drawings as needed. It is noted that detailed description will not be provided more than necessary in some cases. For example, detailed description of already well-known facts and repeated description of substantially the same constituent elements may not be provided. This is for the purpose of avoiding unnecessary redundancy of the following description and facilitating understanding by those skilled in the art.

The accompanying drawings and the following description are provided by the present inventor(s) for sufficient understanding of the present disclosure by those skilled in the art, and it is not intended to limit the subject matter described in claims thereto.

First Embodiment

FIG. 1is a perspective view showing an appearance of a reading device20according to a first embodiment. The reading device20includes a housing21having an opening in an upper portion (first surface) and a reading window member22fitted in the opening.

The housing21houses various members described later. A surface to be read of a reading object10is placed on an upper surface of the reading window member22. The reading window member22is made of light transmissive glass or resin such as organic glass. An antireflection sheet, an antireflection film, an anti-scattering sheet, etc. may be affixed to the surface of the reading window member22. The reading device20includes an imaging device therein, and the imaging device images the surface to be read through the reading window member22.

FIG. 2is a view showing an example of the surface to be read of the reading object10. The reading object10is a passport, for example. A face photograph11, passport data12, and aFIG. 13for forgery prevention, etc. are arranged on the surface to be read. TheFIG. 13for forgery prevention is printed by using a paint reacting with ultraviolet rays to fluoresce. The reading device20optically reads information such as the face photograph11, the passport data12, and theFIG. 13from the surface to be read of the reading object10.

FIG. 3is a cross-sectional view showing a configuration of the reading device20corresponding to a cross section taken along A-A′ ofFIG. 1. As described above, the reading device20includes the housing21and the reading window member22. The reading device20includes first irradiation parts27a,27bemitting an infrared light and second irradiation parts28a,28bemitting a visible light. The reading device20includes an imaging device26and a third irradiation part29emitting an ultraviolet light. The reading device20includes a first diffusion part and a second diffusion part. The first diffusion part is made up of a light-transmitting first diffusion plate24aand a light-transmitting second diffusion plate25a. The second diffusion part includes a light-transmitting third diffusion plate24band a light-transmitting fourth diffusion plate25b. The reading device20includes light-diffusing reflection plates23a,23b.

The first diffusion part and the second diffusion part transmit and diffuse an incident light. As used herein, “transmit and diffuse” means that light transmitted through an object spreads and scatters at various angles due to fine irregularities of the object. The first diffusion part and the second diffusion part are made of glass or organic glass such as acrylic.

The light-diffusing reflection plates23a,23bdiffusely reflect the incident light. As used herein, “diffusely reflect” means that light incident on an object is reflected at various angles due to fine irregularities of the object. The reflection plates23a,23bof this embodiment are made up of white plates containing a white material having high diffusivity; however, the present invention is not limited thereto. The reflection plates23a,23bmay be made up of, for example, a reflection plate made of aluminum etc. to which white paint with high diffuse reflectivity is applied, a reflection sheet, or a white glass or resin plate material having high diffuse reflectivity. Although the reflection plates23a,23bof this embodiment are arranged on a side wall inside the housing21, the reflection plates may be formed integrally with the housing21. Alternatively, an entire side wall of the housing21may be formed as a reflection plate.

The first irradiation parts27a,27binclude a substrate and multiple infrared light sources mounted on the substrate. The infrared light sources emit an infrared light. A circuit driving the infrared light sources is disposed on the substrate. The first irradiation parts27a,27bemit near infrared rays having a wavelength of 0.7 to 2.5 μm, for example. The first irradiation parts27a,27beach include six infrared light LEDs as infrared light sources. The six infrared light LEDs are arranged in a line in a depth direction (a direction orthogonal to both a left-right direction and an up-down direction) inFIG. 3. The first irradiation parts27a,27binclude surface-mounted infrared light LEDs; however the first irradiation parts27a,27bmay include infrared light LEDs having other shapes such as shell-type LEDs. The first irradiation parts27a,27bare used for clearly imaging characters of the passport data12on the surface to be read ofFIG. 2, for example. The infrared LEDs used in this embodiment have a half-angle of about 50 degree. As used herein, the “half-angle” refers to an angle at which the light intensity falls to one-half of the light intensity in the front direction.

The second irradiation parts28a,28binclude a substrate and multiple visible light sources mounted on the substrate. The visible light sources emit a visible light. A circuit for driving the visible light sources is disposed on the substrate. The second irradiation parts28a,28beach include four white light LEDs as the visible light sources. The four white light LEDs are arranged in a line in the depth direction (a direction orthogonal to both the left-right direction and the up-down direction) inFIG. 3. The second irradiation parts28a,28binclude surface-mounted white light LEDs; however the second irradiation parts28a,28bmay include infrared light LEDs having other shapes such as a shell-type LEDs. The white light LEDs used in this embodiment have a half-angle of about 120 degree.

The imaging device26images the surface to be read of the reading object10placed on the upper surface of the reading window member22, via the reading window member22. The imaging device26is made up of an imaging sensor, a wide-angle lens, a circuit driving the imaging sensor, etc. Since the imaging device26includes the wide-angle lens, the imaging device26can be disposed such that the entire surface to be read falls within the angle of view without increasing a distance between the reading window member22and the imaging device26. Therefore, the reading device20does not need to include a mirror bending an optical path from the surface to be read and focusing light on the imaging device. Thus, the reading device20can acquire an image with less illumination unevenness caused by the visible light sources.

The third irradiation part29includes a substrate and multiple ultraviolet light sources mounted on the substrate. The ultraviolet light sources emit an ultraviolet light. A circuit for driving the multiple ultraviolet light sources is disposed on the substrate. The ultraviolet light sources emit an ultraviolet light having a wavelength of about 10 to 400 nm. The third irradiation part29includes eight ultraviolet light LEDs as the ultraviolet light sources. The third irradiation part29includes a shell-type ultraviolet LEDs; however the third irradiation part29may include LEDs having other shapes such as surface-mounted LEDs. The ultraviolet LEDs used in this embodiment have a half-angle of about 15 degree. The third irradiation part29is used for causing theFIG. 13for forgery prevention ofFIG. 2to fluoresce, for example.

InFIG. 3, the reading window member22is fitted into the opening in the upper portion of the housing21. The imaging device26is disposed on a bottom portion (on the side of a second surface facing the first surface) inside the housing21under the reading window member22such that the entire reading window member22falls within the angle of view.

The reflection plate23ais disposed on a left side wall (first side wall) connecting the first surface and the second surface inside the housing21below the reading window member22. The first diffusion plate24ais disposed on the left side wall inside the housing21and is inclined upward. The second diffusion plate25ais disposed above the light-transmitting first diffusion plate24aand is inclined downward relative to the left side wall inside the housing21. The first diffusion plate24ais inclined at an angle of θ1 _relative to the normal line of the left side wall inside the housing21. The second diffusion plate25ais inclined at an angle of θ2relative to the normal line of the left side wall inside the housing21. For example, θ1is 30 degree, and θ2is 50 degree.

The second irradiation part28ais disposed on the left side wall inside the housing21below the reflection plate23a. The first irradiation part27ais disposed on the bottom portion of the housing21to face the first diffusion plate24a.

The reflection plate23bis disposed on a right side wall (second side wall) connecting the first surface and the second surface inside the housing21, symmetrically to the reflection plate23aabout an optical axis of the imaging device26. The third diffusion plate24bis disposed on the right side wall inside the housing21and is inclined upward. The fourth diffusion plate25bis disposed above the third diffusion plate24band is inclined downward relative to the right side wall inside the housing21. The third diffusion plate24bis inclined upward at an angle of θ3relative to the normal line of the right side wall inside the housing21. The fourth diffusion plate25bis inclined downward at an angle of θ4relative to the normal line of the right side wall inside the housing21. For example, θ3is 30 degree, and θ4is 50 degree.

The second irradiation part28bis disposed on the right side wall inside the housing21symmetrically to the second irradiation part28aabout the optical axis of the imaging device26. The first irradiation part27bis disposed on the bottom portion of the housing21to face the third diffusion plate24b, symmetrically to the first irradiation part27aabout the optical axis of the imaging device26.

The third irradiation part29is disposed on a far side wall inside the housing21on the upper side (first surface side) of the first diffusion part and the second diffusion part.

The operation of the reading device20having the above configuration will be described. The surface to be read of the reading object10is placed on the upper surface of the reading window member22. The reading device20irradiates the surface to be read of the reading object10with infrared light, visible light, and ultraviolet light and captures an image of the surface to be read to acquire the image. The reading device20further includes a communication part (not shown) and transmits the captured image to an external device connected via the communication part. The external device receives the captured image and uses the image for various analyses.

Specifically, the first irradiation parts27a,27bemit an infrared light. The second irradiation parts28a,28bemit a visible light. The infrared light from the first irradiation parts27a,27band the visible light from the second irradiation parts28a,28bare diffused by the first diffusion part, the second diffusion part, and the reflection plates23a,23b. The surface to be read of the reading object10is illuminated by the diffused infrared light or visible light. The imaging device26captures an image of the surface to be read of the reading object10to acquire the image. The communication part transmits the acquired image to an external device.

The third irradiation part29emits an ultraviolet light. The ultraviolet light is directly applied to the surface to be read of the reading object10without being diffused by the first diffusion part, the second diffusion part, and the reflecting plates23a,23b. The directly applied ultraviolet light causes theFIG. 13for forgery prevention disposed on the surface to be read of the reading object10to fluoresce. The imaging device26captures an image of the surface to be read of the reading object10to acquire the image. The communication part transmits the acquired image to an external device.

3. Diffusion of Light

FIG. 4is a view showing how the visible light from the second irradiation part28ais diffused inside the reading device20. A portion of the visible light from the second irradiation part28aenters the first diffusion plate24a. The first diffusion plate24atransmits and diffuses the visible light entering from the second irradiation part28a.

A portion of the visible light diffused by the first diffusion plate24aenters the reflection plate23a. The reflection plate23adiffusely reflects the visible light entering from the first diffusion plate24a. A portion of the visible light diffusely reflected from the reflection plate23aenters the second diffusion plate25a. The second diffusion plate25atransmits and diffuses the visible light entering from the reflection plate23a. A portion of the visible light transmitted and diffused from the second diffusion plate25ais transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the visible light transmitted through the reading window member22.

Another portion of the visible light diffused from the first diffusion plate24aenters the second diffusion plate25a. The second diffusion plate25atransmits and diffuses the visible light entering from the first diffusion plate24a. A portion of the visible light transmitted and diffused from the second diffusion plate25ais transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the visible light transmitted through the reading window member22.

Yet another portion of the visible light diffused from the second irradiation part28aenters the third diffusion plate24b. The third diffusion plate24btransmits and diffuses the visible light entering from the second irradiation part28a.

A portion of the visible light diffused from the third diffusion plate24benters the reflection plate23b. The reflection plate23bdiffusely reflects the visible light entering from the third diffusion plate24b. A portion of the visible light diffusely reflected from the reflection plate23benters the fourth diffusion plate25b. The fourth diffusion plate25btransmits and diffuses the visible light entering from the reflection plate23b. A portion of the visible light transmitted and diffused from the fourth diffusion plate25bis transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the visible light transmitted through the reading window member22.

Another portion of the visible light diffused from the third diffusion plate24benters the fourth diffusion plate25b. The fourth diffusion plate25btransmits and diffuses the visible light entering from the third diffusion plate24b. A portion of the visible light transmitted and diffused from the fourth diffusion plate25bis transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the visible light transmitted through the reading window member22.

The visible light from the second irradiation part28bis diffused in a direction symmetrical to the visible light from the second irradiation part28adescribed above about the optical axis of the imaging device26and illuminates the surface to be read.

In this embodiment, the half-angle of the white light LEDs used as the visible light sources is about 120 degree. The first diffusion plate24aand the third diffusion plate24bare arranged to prevent the visible light from the visible light from reaching the surface to be read over an angular range of the half-angle of the white light LEDs. Therefore, the surface to be read is not directly illuminated by the visible light having a high light intensity. Thus, the reading device20of this embodiment can acquire an image with less illumination unevenness caused by the visible light sources.

In this embodiment, the reading device20has gaps between the imaging device26and an upper edge of the first diffusion plate24aand between the imaging device26and an upper edge of the third diffusion plate24b. Since a portion of the visible light from the second irradiation parts28a,28bpasses through the gaps, the reading device20can acquire an image with less illumination unevenness caused by the visible light sources. Additionally, the first diffusion plate24aand the third diffusion plate24bhave a size not coming into the field of view of the imaging device26, and the second diffusion plate25aand the fourth diffusion plate25bare inclined so as not to come into the field of view of the imaging device26.

FIG. 5is a view showing how the infrared light from the first irradiation part27ais diffused inside the reading device. A portion of the infrared light from the first irradiation part27aenters the first diffusion plate24a. The first diffusion plate24atransmits and diffuses the infrared light entering from the first irradiation part27a.

A portion of the infrared light diffused from the first diffusion plate24aenters the reflection plate23a. The reflection plate23adiffusely reflects the infrared light entering from the first diffusion plate24a. A portion of the infrared light diffused from the reflection plate23aenters the second diffusion plate25a. The second diffusion plate25atransmits and diffuses the infrared light entering from the reflection plate23a. A portion of the infrared light diffused from the second diffusion plate25ais transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the infrared light transmitted through the reading window member22.

Another portion of the infrared light diffused from the first diffusion plate24aenters the second diffusion plate25a. The second diffusion plate25atransmits and diffuses the infrared light entering from the first diffusion plate24a. A portion of the infrared light diffused from the second diffusion plate25ais transmitted through the reading window member22. The surface to be read of the reading object10placed on the reading window member22is illuminated by the infrared light transmitted through the reading window member22.

The infrared light from the first irradiation part27bis diffused in a direction symmetrical to the infrared light from the first irradiation part27adescribed above about the optical axis of the imaging device26and illuminates the surface to be read.

In this embodiment, the half-angle of the infrared LEDs used as the infrared light sources is about 50 degree. The first diffusion plate24aand the third diffusion plate24bare arranged to prevent the infrared light from the infrared light sources from reaching the surface to be read over an angular range of the half-angle of the infrared light LEDs. Therefore, the surface to be read is not illuminated by the infrared light having a high light intensity. Thus, the reading device20of this embodiment can acquire an image with less illumination unevenness caused by the infrared light sources.

The ultraviolet light from the third irradiation part29is transmitted through the reading window member22without passing through the first diffusion part, the second diffusion part, and the reflection plates23a,23b. The ultraviolet light transmitted through the reading window member22causes theFIG. 13for forgery prevention ofFIG. 2to fluoresce, for example.

The reading device20of this embodiment allows the ultraviolet light from the third irradiation part29to reach the surface to be read without passing through the first diffusion part, the second diffusion part, and the reflection plates23a,23b. As a result, the first diffusion part, the second diffusion part, and the reflecting plates23a,23bcan be made of a resin material that may be deteriorated by ultraviolet rays or a resin material absorbing ultraviolet rays.

As described above, the reading device20includes the housing21, the first irradiation part27a, the imaging device26, and the first diffusion part. The housing21has an opening in the upper portion (first surface) with the transparent reading window member22disposed therein. The first irradiation part27aemits an infrared light. The imaging device26is disposed on the bottom portion (second surface) facing the upper portion inside the housing such that the optical axis is directed to the reading window member22. The first diffusion part is disposed on the left side wall (first side wall) connecting the upper portion and the bottom portion inside the housing21. The first diffusion part diffuses the infrared light from the first irradiation part27a. The first diffusion part is made up of the light-transmitting first diffusion plate24aand the light-transmitting second diffusion plate25a. The first diffusion plate24ais disposed on the bottom portion side of the left side wall and inclined toward the upper portion. The second diffusion plate25ais disposed on the upper portion side of the left side wall and inclined toward the bottom portion.

The first irradiation part27ais disposed between the first diffusion plate24aand the bottom portion of the housing21.

As a result, the infrared light from the first irradiation part27ais diffused through the first diffusion part and applied to the reading window member22, so that the reading device20can acquire an image with less illumination unevenness caused by the first irradiation part27a.

The reading device20further includes the light-diffusing reflection plate23a. The reflection plate23ais attached to the left side wall of the housing21.

As a result, the reflection plate23adiffusely reflects the light from the first diffusion part, so that the reading device20can efficiently use the light.

The reading device20further includes the second irradiation part28aemitting a visible light. The second irradiation part28ais disposed between the first diffusion plate24aand the bottom portion of the housing21. The visible light from the second irradiation part28ais diffused by the first diffusion part.

As a result, the visible light from the second irradiation part28ais diffused through the first diffusion part and applied to the reading window member22, so that the reading device20can acquire an image with less illumination unevenness caused by the second irradiation part28a.

The reading device20further includes the third irradiation part29emitting an ultraviolet light. The third irradiation part29is disposed between the upper portion of the housing21and the first diffusion part.

As a result, the ultraviolet light from the third irradiation part29reaches the surface to be read without passing through the first diffusion part and the reflection plate23a. Therefore, the first diffusion part, the second diffusion part, and the reflecting plates23a,23bcan be made of a resin material that may be deteriorated by ultraviolet rays or a resin material absorbing ultraviolet rays.

The imaging device26is disposed such that the entire reading window member22is included in a range of an angle of view. In this regard, the imaging device26may include a wide-angle lens.

As a result, the imaging device26can be disposed such that the entire surface to be read falls within the angle of view without increasing the distance between the reading window member22and the imaging device26, so that the reading device20does not need to include a mirror bending an optical path from the surface to be read and focusing light on the imaging device as in the conventional reading device. Therefore, the present disclosure can provide a small-sized reading device.

The reading device20has a gap between the upper edge of the first diffusion plate24aand the imaging device26.

As a result, a portion of the visible light from the second irradiation parts28a,28bpasses through the gap, so that the reading device20can acquire an image with less illumination unevenness caused by the visible light sources.

The first diffusion plate24ais disposed such that the infrared light from the first irradiation part27ais prevented from directly reaching the reading window member22over the angular range of the half-angle of the first irradiation part.

As a result, the surface to be read is not directly illuminated by the infrared light having a high light intensity. Therefore, the reading device20can acquire an image with less illumination unevenness caused by the infrared light source.

The first diffusion plate24ais disposed such that the visible light from the second irradiation part28ais prevented from directly reaching the reading window member22over the angular range of the half-angle of the second irradiation part.

As a result, the surface to be read is not directly illuminated by the visible light having a high light intensity. Therefore, the reading device20can acquire an image with less illumination unevenness caused by the visible light sources.

The reading device20further includes the second diffusion part. The second diffusion part is disposed on the right side wall (second side wall) facing the left side wall inside the housing21. The second diffusion part diffuses the infrared light from the first irradiation part27b. The second diffusion part is made up of the light-transmitting third diffusion plate24band the light-transmitting fourth diffusion plate25b. The third diffusion plate24bis disposed on the bottom portion side of the right side wall and inclined toward the upper portion. The fourth diffusion plate25bis disposed on the upper portion side of the right side wall and inclined toward the bottom portion.

The reading device20further includes the light-diffusing reflection plate23b. The reflection plate23bis attached to the right side wall of the housing21.

As a result, the reflection plate23bdiffusely reflects the light from the second diffusion part, so that the reading device20can efficiently use the light.

The first irradiation part27bis disposed between the first diffusion plate24aand the bottom portion of the housing21.

As a result, the infrared light from the first irradiation part27bis diffused through the first diffusion part and applied to the reading window member22, so that the reading device20can acquire an image with less illumination unevenness caused by the first irradiation part27b.

The reading device20further includes the second irradiation part28bemitting a visible light. The second irradiation part28bis disposed between the first diffusion plate24aand the bottom portion of the housing21.

As a result, the visible light from the second irradiation part28bis diffused through the second diffusion part and applied to the reading window member22, so that the reading device20can acquire an image with less illumination unevenness caused by the second irradiation part28b.

The first diffusion plate24ahas a size not coming into the field of view of the imaging device26, and the second diffusion plate25ais inclined so as not to come into the field of view of the imaging device26.

Second Embodiment

In this embodiment, some configurations of a reading device having a configuration different from the first embodiment will be described.FIGS. 6A, 6B, 7A, 7B, and 8are cross-sectional views showing other embodiments of the reading device.

A reading device20A ofFIG. 6Ais different from that of the first embodiment ofFIG. 3in the arrangement of the second irradiation parts28a,28bemitting a visible light. In the reading device20of the first embodiment, as shown inFIG. 3, the second irradiation part28ais disposed on the left side wall inside the housing21below the light-diffusing reflection plate23a. On the other hand, the second irradiation part28aof the reading device20A ofFIG. 6Ais disposed on the left side surface of the imaging device26such that the optical axis of the second irradiation part28ais orthogonal to the left side wall inside the housing21. Similarly, the second irradiation part28bof the reading device20A is disposed symmetrically to the second irradiation part28aon the right side of the imaging device26such that the optical axis of the second irradiation part28bis orthogonal to the right side wall inside the housing21.

A reading device20B ofFIG. 6Bis different from the first embodiment ofFIG. 3in the arrangement of the light-transmitting first diffusion plate24a. In the reading device20of the first embodiment, as shown inFIG. 3, the first diffusion plate24ais disposed on the left side wall inside the housing21and is inclined upward. On the other hand, the first diffusion plate24aofFIG. 6Bis disposed orthogonally to the left side wall inside the housing21. The third diffusion plate24bis disposed symmetrically to the first diffusion plate24aand orthogonally to the right side wall inside the housing21.

A reading device20C ofFIG. 7Aincludes a fourth irradiation part30ainstead of the first irradiation part27aand the second irradiation part28ain the configuration of the first embodiment (FIG. 3). The reading device20C further includes a fourth irradiation part30binstead of the first irradiation part27band the second irradiation part28bin the configuration ofFIG. 3.

Each of the fourth irradiation parts30a,30bincludes a substrate and multiple infrared light sources and visible light sources mounted on the substrate. The fourth irradiation part30aincludes four white light LEDs30a1as visible light sources and six infrared light LEDs30a2as infrared light sources. The fourth irradiation part30bincludes four white light LEDs30b1as visible light sources and six infrared light LEDs30b2as infrared light sources.

In the fourth irradiation part30a, the six infrared light LEDs30a2are arranged in a line on the substrate. The four white light LEDs30a1are arranged in a line on the substrate adjacently to the line of the infrared light LEDs30a2. The fourth irradiation part30bhas the same configuration as the fourth irradiation part30a.

In the reading device20C, the fourth irradiation part30ais disposed at a tilt on the bottom surface of the housing21such that that the optical axis thereof is orthogonal to a principal surface of the first diffusion plate24a. Similarly, the fourth irradiation part30bis also disposed at a tilt on the bottom surface of the housing21such that the optical axis thereof is orthogonal to a principal surface of the third diffusion plate24b.

InFIG. 7B, the first diffusion plate24ais disposed orthogonally to the left side wall inside the housing21. The third diffusion plate24bis also disposed orthogonally to the right side wall inside the housing21.

The first irradiation part27ais disposed on the bottom portion of the housing21below the first diffusion plate24asuch that the optical axis thereof is orthogonal to a principal surface of the first diffusion plate24a. Similarly, the first irradiation part27bis disposed on the bottom portion of the housing21below the third diffusion plate24bsuch that the optical axis thereof is orthogonal to a principal surface of the third diffusion plate24b.

A reading device20E ofFIG. 8is different from the first embodiment (FIG. 3) in the configuration of the irradiation parts and the diffusion parts. The reading device20ofFIG. 3includes the third irradiation part29emitting an ultraviolet light on the far side wall inside the housing21. On the other hand, the reading device20E includes the third irradiation part29also on the left and right side walls and a near side wall inside the housing21. The reading device20ofFIG. 3includes the third irradiation part29emitting an ultraviolet light on the left and right side walls inside the housing21. On the other hand, the reading device20E includes the third irradiation part29also on the left and right side walls and the near side wall inside the housing21.

FIGS. 9 and 10are views for explaining the reading device20E ofFIG. 8.FIG. 9is a top view of the reading device20E with the reading window member22and the third irradiation part29ofFIG. 8removed. The reading device20E includes four transmissive diffusion plates25cto25fas shown inFIG. 9instead of the second diffusion plate25aand the fourth diffusion plate25bin the configuration of the first embodiment (FIG. 3). As shown inFIGS. 9 and 10, the reading device20E further includes four ribs33ato33dvertically disposed on the bottom portion of the housing21and arranged to surround the side portions of the imaging device26. The diffusion plates25cto25fare respectively supported by the ribs33ato33dand the walls inside the housing21.

The reading device20E includes a transmissive diffusion plate24cinstead of the first diffusion plate24aand the third diffusion plate24bin the configuration ofFIG. 3. As shown inFIG. 8, the diffusion plate24cis disposed between the ribs33ato33dand the walls inside the housing21.

FIG. 11is a top view of the reading device20E with the diffusion plates25cto25fand the diffusion plate24cremoved inFIGS. 8 and 9. The reading device20of the first embodiment (FIG. 3) includes light-diffusing reflection plates23a,23bon the left and right side walls inside the housing21. On the other hand, the reading device20E also includes light-diffusing reflection plates23c,23don the far and near side walls inside the housing21.

The reading device20E includes irradiation parts31a,31b,32a,32bofFIG. 11instead of the first irradiation parts27a,27band the second irradiation parts28a,28bin the configuration of the first embodiment (FIG. 3). The irradiation parts31a,31b,32a,32beach include a substrate and visible and infrared light sources mounted on the substrate.

The irradiation parts31a,32bare arranged close to the far side wall inside the housing21. The irradiation part31aincludes one white light LED31a1as the visible light source and one infrared light LED31a2as the infrared light source. On the substrate of the irradiation part31a, the white light LED31a1is disposed at the corner closest to the imaging device26, and the infrared light LED31a2is disposed at the corner farthest from the imaging device26.

The irradiation part32bincludes two infrared light LEDs32b1,32b3as the infrared light sources and one white light LED32b2as the visible light source. On the substrate of the irradiation part32b, the infrared light LED32b1is disposed close to the center in the left-right direction of the far side wall inside the housing21, and the white light LED32b2and the infrared light LED32b3are respectively arranged symmetrically to the white light LEDs31a1and the infrared light LEDs31a2of the irradiation part31a.

The irradiation parts31b,32aare arranged close to the near side wall inside the housing21. The irradiation part31bincludes one white light LED31b1as the visible light source and one infrared light LED31b2as the infrared light source. The irradiation part31bis disposed symmetrically to the irradiation part31awith respect to the optical axis of the imaging device26. The irradiation part32aincludes two infrared light LEDs32a1,32a3as the infrared light sources and one white light LED32a2as the visible light source. The irradiation part32ais disposed symmetrically to the irradiation part32bwith respect to the optical axis of the imaging device26.

In the configuration described above, the reading device20E can include the diffusion plates25cto25fsymmetrically in four directions, so that an image with less illumination unevenness caused by the irradiation parts31a,31b,32a,32bcan be acquired.

OTHER EMBODIMENTS

As described above, the embodiments have been described as exemplification of the techniques disclosed in this application. However, the techniques in the present disclosure are not limited thereto and are also applicable to embodiments in which modifications, replacements, additions, omissions, etc. are appropriately made. Additionally, the constituent elements described in the embodiments can be combined to provide a new embodiment.

In the first embodiment, the reading device20includes the point light sources as the visible light sources, the infrared light sources, and the ultraviolet light sources; however, the present invention is not necessarily limited thereto. For example, a line light source or a surface light source made of an organic EL material may be used.

In the first embodiment, the first irradiation parts27a,27beach include six infrared light LEDs as the infrared light sources; however, the number of the included infrared light LEDs may be different.

In the first embodiment, the second irradiation parts28a,28beach include four white light LEDs as the visible light sources; however, the number of the included white light LEDs may be different.

In the first embodiment, the reading device20uses the white light LEDs as the visible light sources; however, LEDs other than the white light LEDs may be used.

In the first embodiment, the reading device20includes the visible light sources and the ultraviolet light sources; however, the reading device20may not include the visible light sources and/or the ultraviolet light sources.

In the first embodiment, the second irradiation parts28a,28bare respectively disposed on the side walls inside the housing21; however, the present invention is not necessarily limited thereto. The second irradiation parts28a,28bmay be disposed at other positions such that the first diffusion plate24aand the third diffusion plate24bprevent the visible light from the second irradiation parts28a,28bfrom reaching the reading window over the angular range of the half-angle of the second irradiation parts28a,28b.

In the first embodiment, the first irradiation parts27a,27bare disposed to face the first diffusion plate24aand the third diffusion plate24b, respectively; however, the present invention is not necessarily limited thereto. The first irradiation parts27a,27bmay be disposed at other positions such that the first diffusion plate24aand the third diffusion plate24bprevent the infrared light from the first irradiation parts27a,27bfrom reaching the reading window over the angular range of the half-angle of the first irradiation parts27a,27b.

In the first embodiment, the first irradiation parts27a,27b, the second irradiation parts28a,28b, the first diffusion part (the first diffusion plate24a, the second diffusion plate25a), the second diffusion part (the third diffusion plate24b, the fourth diffusion plate25b), and the reflecting plates23a,23bare paired constituent elements symmetrical about the optical axis of the imaging device26; however, the present invention is not necessarily limited thereto. The constituent elements such as the first irradiation part27a, the second irradiation part28a, the first diffusion part (the first diffusion plate24a, the second diffusion plate25a), and the reflection plate23amay be included only on one side.

In the first embodiment, the optical axis of the imaging device26is in the vertical direction in the first embodiment; however, the present invention is not necessarily limited thereto. The optical axis of the imaging device26may be in a horizontal direction or an obliquely upward direction. The imaging device26is disposed on the bottom portion inside the housing21directly below the reading window member22such that the optical axis is directed to the reading window member22. For example, the housing21has an opening on a side surface (first surface), and the reading window member22is disposed in the opening. The imaging device26may be disposed on a side surface (second surface) facing the side surface (first surface) inside the housing such that the optical axis is directed to the reading window member22.

In the first embodiment, the first irradiation parts27a,27binclude the substrate and the multiple infrared light sources mounted on the substrate, and the second irradiation parts28a,28binclude the substrate and the multiple visible light sources mounted on the substrate, and the third irradiation part29includes the substrate and the multiple ultraviolet light sources mounted on the substrate; however, the present invention is not necessarily limited thereto. The first irradiation part may include only multiple infrared light sources, the second irradiation part may include only multiple visible light sources, and the third irradiation part may include only multiple ultraviolet light sources. In this case, the substrate (circuit) controlling the light sources may be disposed inside the housing21.

In the reading device20C ofFIG. 7A, the fourth irradiation part30aincludes the six infrared light LEDs30a2as the infrared light sources; however, the number of the included infrared light LEDs30a2may be different. The fourth irradiation part30bincludes the six infrared light LEDs30b2as the infrared light sources; however, the number of the included infrared light LEDs30b2may be different.

In the reading device20C ofFIG. 7A, the fourth irradiation part30aincludes the four white light LEDs30a1as the white light sources; however, the number of the included white light LEDs30a1may be different. The fourth irradiation part30bincludes the four infrared light LEDs30b1as the infrared light sources; however, the number of the included infrared light LEDs30b1may be different.

In the first embodiment, the third irradiation part29is disposed between the upper portion of the housing21and the first diffusion part; however, the third irradiation part29may be disposed at a different position. For example, the third irradiation part29may be disposed between the first diffusion part and the bottom portion.

In the embodiment of the present disclosure, a passport has been described as an example of the reading object10; however, the present invention is not limited thereto. The reading object10may be any of those readable by the imaging device26such as a license, a document, a photograph, and a form.

The embodiments have been described as exemplification of the techniques in the present disclosure. The accompanying drawings and the detailed description have been provided for this purpose.

Therefore, the constituent elements described in the accompanying drawings and the detailed description may include not only the constituent elements essential for solving the problem but also constituent elements not essential for solving the problem so as to illustrate the techniques. Thus, even though these non-essential constituent elements are included in the accompanying drawings and the detailed description, these non-essential constituent elements should not immediately be recognized as being essential.

Since the embodiments described above are intended to illustrate the techniques in the present disclosure, various modifications, replacements, additions, omissions, etc. can be made within the claims and the scope equivalent thereto.