JP2011124741A - Illuminator and image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator for making the depth of illumination relatively deeper while improving the light-harvesting property of light from a light source and fluctuation in illuminance, and to provide an image reading apparatus using the same. <P>SOLUTION: The illuminator includes: the light source 2 for emitting light to an irradiation part 1a of a document 1 over a read width; a light guiding body 6 which is arranged on an illumination axis connecting the light source 2 to the illumination part 1a, collects the light of the light source 2 on a curved surface 6b to make the light the parallel light, and irradiates the parallel light from a flat part 6a provided at a position opposing the curved surface 6b; a light limiting means 4 which is provided with a slit part 4a at a position corresponding to the illumination axis by shielding the light in the vicinity, and limits the light incoming to the curved surface 6b over the read width; and a case 5 which surrounds the light of the light source 2 reaching the light limiting means 4 except at least the irradiation part 1a direction of the illumination axis to place the light source 2, and stores or holds the light guiding body 6 and the light limiting means 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an illumination device equipped with an LED light source and an image reading device using the same.

An illumination device used for an image reading device or the like illuminates an object to be read such as a document with light from a light source arranged linearly over a reading width direction. In general, in order to improve illumination efficiency, a light guide having a circular or arc cross-sectional shape is used. A light guide of a conventional illumination device is assumed to efficiently illuminate a reading object by condensing light from a light source at an arc portion. Uses a rod-shaped lens 14 that condenses the light from the LED 12 at the arc portion on the LED 12 side and the arc portion on the emission side, and scatters the light by the scattering sheet 2 near the irradiation surface 3 to widen the effective irradiation width. A light emitting element array is disclosed.

FIG. 1 (see Patent Document 2) of Japanese Patent Application Laid-Open No. 2009-259545 has a long casing 2 having an opening 1 extending linearly in the longitudinal direction and a predetermined interval in the longitudinal direction. And a plurality of LED light sources 4 disposed inside the housing 2, and the housing 2 has a diffuse reflection surface 5 inside thereof, and the plurality of LED light sources 4 have diffused reflection of the emitted light. A light emitting device 10 positioned inside the housing 2 so as to be irradiated toward the surface 5 is disclosed.

FIG. 2 (see Patent Document 3) of Japanese Patent Laid-Open Publication No. 2006-14895 is an illuminating device in which a light emitting unit 13 is provided at an end of a light guide 11 having a rectangular cross section and propagates light in the longitudinal direction of the light guide 11. The light scattering pattern 20 for scattering the light incident on the light guide 11 is formed on one side surface 11 a in the longitudinal direction of the light guide 11, and the side surface 11 b facing the side surface 11 a is an exit surface exposed from the case 12. Is disclosed.

Japanese Laid-Open Patent Publication No. 1-144771 (FIG. 1) JP 2009-259545 A (FIG. 1, [paragraph 0013]) Japanese Patent Laying-Open No. 2006-148956 (FIG. 2)

However, although the thing of patent document 1 can improve the illuminance fluctuation | variation by light-scattering with the scattering sheet 2, since the diffusion sheet 2 other than the rod-shaped lens 14 is required, a member increases. There are challenges.

Patent Document 2 describes a configuration in which the center axis of the emitted light is positioned so as to face the diffuse reflection surface 5, and substantially all of the light emitted from the LED light source 4 is at least once as a diffuse reflection surface. 5, it is emitted from the opening 1, and the length of the optical path to the reading target becomes long, and there is a problem that the irradiation efficiency is low because the light is not condensed.

In the device described in Patent Document 3, since the light emission direction is not limited narrowly, the attenuation of light intensity is reduced and the light distribution is improved, but the light propagating inside the light guide 11 is confined. Since the white case 12 is required, there is a problem that the number of members increases. In addition, since a large number of light emitting elements 13a, 13b, and 13c cannot be disposed at the end of the light guide 11, there is a problem that it is difficult to apply to an image reading apparatus that requires a relatively high illuminance and a high reading speed. is there.

The present invention has been made in order to solve the above-described problems, and uses an illuminating device having a relatively deep illumination depth while improving the condensing property of light from a light source and fluctuation of illuminance, and the same. An object is to provide an image reading apparatus.

An illumination device according to a first aspect of the present invention is disposed on a light source that irradiates light to an irradiating portion of a document over a reading width, and an irradiation axis that connects the light source and the irradiating portion. A light guide that irradiates light from a flat part provided at a position facing the curved surface part and a slit part at a position corresponding to the irradiation axis while shielding the surroundings. A light restricting means for restricting light incident on the curved surface portion over a reading width, and surrounding the light of the light source reaching the light restricting means except at least an irradiation portion direction of the irradiation axis. And a housing that houses or holds the light guide and the light limiting means.

In the illumination device according to a second aspect of the present invention, the width of the flat portion of the light guide is made shorter than the width of the slit portion of the light limiting means, and parallel light is emitted from the flat portion of the light guide. The irradiating part is irradiated with refracted light from the outer side of the flat part.

According to a third aspect of the present invention, there is provided the lighting device according to the first or second aspect, wherein the light limiting means is a light shielding resin layer applied or deposited on the curved surface portion of the light guide.

According to a fourth aspect of the present invention, in the lighting device according to the first or second aspect, the light restricting means is provided with a long groove in the casing to form the slit portion, and the periphery of the long groove is shielded by a part of the casing. 2.

The illumination device of the invention according to claim 5 is provided with an optical filter that blocks or passes a predetermined optical wavelength between the curved surface portion of the light guide or the light source and the light guide. Any one of them.

An image reading apparatus according to a sixth aspect of the present invention is a light source that irradiates light to an irradiating portion of a document over a reading width, and is disposed on an irradiation axis that connects the light source and the irradiating portion. A light guide that irradiates the parallel light into a parallel light and irradiates the parallel light from a flat portion provided at a position facing the curved surface portion, and a slit portion is provided at a position corresponding to the irradiation axis while shielding the surroundings. Light limiting means for limiting the light incident on the curved surface portion over the reading width, the light of the light source reaching the light limiting means is surrounded at least except for the irradiation portion direction of the irradiation axis, and the light source is placed And an illumination device having a housing that houses or holds the light guide and the light limiting unit, a lens body that converges light reflected from the document, and a light receiving unit that receives light converged by the lens body. It is provided.

In the image reading device according to the seventh aspect of the invention, the width of the flat portion of the light guide is made shorter than the width of the slit portion of the light restricting means, and parallel light is transmitted from the flat portion of the light guide. The irradiating part is irradiated with refracted light from the outside of the flat part of the body.

An image reading apparatus according to an eighth aspect of the present invention is the image reading device according to the sixth or seventh aspect, wherein the light limiting means is a light shielding resin layer applied or vapor-deposited on the curved surface portion of the light guide.

  According to a ninth aspect of the present invention, in the image reading apparatus according to the sixth aspect, the light restricting means is provided with a long groove in the casing to form the slit portion, and the periphery of the long groove is shielded by a part of the casing. Or it is a thing of 7.

According to a tenth aspect of the present invention, in the image reading apparatus according to the tenth aspect, an optical filter that blocks or passes a predetermined optical wavelength is installed between the curved surface portion of the light guide or the light source and the light guide. It is a thing in any one.

According to the illuminating device of the present invention, the light from the light source is condensed at the curved surface portion to be parallel light, and the light guide body that irradiates the parallel light from the flat portion provided at the position facing the curved surface portion, and the surroundings. By providing a slit part at a position corresponding to the irradiation axis and blocking light incident on the curved surface part and limiting the light incident on the reading width over the reading width, the light condensing property of the light source and the illumination illuminance can be reduced. Improvements can be made and the illumination depth can be made relatively deep.

According to the image reading apparatus of the present invention, the light from the light source is condensed at the curved surface portion to be parallel light, and the parallel light is irradiated from a flat portion provided at a position facing the curved surface portion, and the surroundings. The light condensing property of the light from the light source and the illumination illuminance are provided by providing a slit portion at a position corresponding to the irradiation axis and using light limiting means for limiting the light incident on the curved surface portion over the reading width. As a result, it is possible to make the illumination depth relatively deep.

1 is a cross-sectional configuration diagram of an image reading apparatus according to Embodiment 1 of the present invention. 1 is a development view of an image reading apparatus according to Embodiment 1 of the present invention. It is a top view of the light source part used for the illuminating device by Embodiment 1 of this invention. It is a schematic cross section explaining the propagation of light incident on the light guide of the lighting device according to Embodiment 1 of the present invention. It is a schematic cross section explaining the propagation of light incident on the light guide of the lighting device according to Embodiment 2 of the present invention. It is a schematic cross section explaining the structure of the illuminating device by Embodiment 3 of this invention. It is a partial cross-section block diagram of the image reading apparatus by Embodiment 4 of this invention. It is a partial cross-section block diagram of the image reading apparatus by Embodiment 4 of this invention. It is a fragmentary sectional block diagram of the image reading apparatus by Embodiment 5 of this invention. It is a fragmentary sectional block diagram of the image reading apparatus by Embodiment 5 of this invention.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a cross-sectional configuration diagram of an image reading apparatus (also referred to as a contact image sensor or CIS) according to Embodiment 1 of the present invention. In FIG. 1, a document 1 is a medium to be read (irradiated body) that is image information of, for example, banknotes, securities, and other general documents. The irradiation unit 1a indicates a light irradiation region on the document 1, and is not configured in a material sense. The light source 2 uses LEDs, and is linearly arranged in an array on the LED substrate 3 along the longitudinal direction (reading width direction).

The light limiting means 4 is made of a light-blocking resin or metal provided with an opening (slit portion) 4a having a certain width along the longitudinal direction. Only the light emitted from the light source 2 that has passed through the opening 4a of the light limiting means 4 is taken out, and the other components are scattered and reflected in the space surrounded by the LED substrate 3, the light limiting means 4 and the housing 5. After that, the light passes through the opening 4a of the light limiting means 4 and is taken out. Therefore, the light extraction efficiency is improved by increasing the reflectance, for example, the surface of the LED substrate 3, the bottom surface of the light limiting unit 4, and the inner surface of the housing 5 are white. The light limiting unit 4 may be integrated with the housing 5.

The light guide 6 is a rod-shaped member extending in the longitudinal direction and serves as a light guide. In this Embodiment 1, the thing of the shape which cut | disconnected some cylindrical light guides and provided the flat part 6a is used, and the light guide 6 is the center position of the irradiation part 1a and the light source 2 There is a cross-sectional center of the light guide 6 on the line (irradiation axis) connecting the two. The flat portion 6a of the light guide 6 is installed so as to be orthogonal to the irradiation axis. The light that has passed through the light limiting means 4 is collected by the curved surface portion 6b of the light guide 6 corresponding to the incident portion of the light guide 6, and parallel light is emitted from the flat portion 6a of the opposing light guide 6. Further, when the width of the flat portion 6a is shorter than the width of the curved surface portion 6b corresponding to the width of the opening 4a, the light reaching the emission side curved surface portion (flat portion outside proximity portion) 6c is emitted from the emission side curved surface portion 6c. The light is refracted and irradiated to the irradiation unit 1a. The light guide 6 is a cylindrical portion cut to form a flat portion 6a. If the flat portion 6a is flat, a rod-shaped light guide 6 having an elliptical cross section or a spindle cross section is used. Also good.

The transmissive member 7 forms a transport path for the document 1 and plays a role in preventing foreign matter mixed in the apparatus, and is made of a transparent resin such as acrylic or polycarbonate, or a transparent glass material. The transmissive member 7 transmits the light emitted from the flat portion 6a or the exit-side curved surface portion 6c of the light guide 6 to irradiate the original 1, and transmits the light reflected by the original 1 to transmit the rod lens array (lens body). ) 8 is incident. The rod lens array 8 converges the reflected light reflected by the document 1 in the irradiation section 1a of the document 1.

The sensor IC 9 is a sensor (light receiving unit) that receives the light converged by the rod lens array 8 and photoelectrically converts it to output an electrical signal. The sensor IC 9 is a photoelectric conversion unit configured by a semiconductor chip or the like, other driving circuits, and the like. It is equipped with. The sensor substrate 10 is a substrate on which the sensor IC 9 and other electronic components are placed. The signal processing IC 11 performs signal processing on the photoelectric conversion output received by the sensor IC 9 and is an ASIC (Application Specific Integrated Circuit) that performs signal processing in conjunction with the CPU and RAM. The ASIC 11 is placed on the sensor substrate 10 together with other electronic components. The external connector 112 is used for an input / output signal interface including the photoelectric conversion output of the sensor IC 9 and its signal processing output.

The housing 5 is a metal that houses or holds the LED substrate 3, the light limiting means 4, the light guide 6, the transmission body 7, the rod lens array 8, and the sensor substrate 10, or a plastic resin having at least a partial light-shielding property. And has a space for accommodating the LED board 3 on which the light source 2 is mounted from the end in the longitudinal direction in a sliding manner. The space of the housing 5 has a reflection wall surface that surrounds the light from the light source 2 including the LED substrate 3 except in the direction of the irradiation unit 1a. The light source 2, the light limiting unit 4, the light guide 6, and a part of the housing 5 placed on the LED substrate 3 are referred to as a lighting device.

A platen 13 extending along the longitudinal direction is provided on the transport side of the document 1 of the transmission body 7. The platen 13 presses the document 1 against the transparent body 7 and rotates to feed the document 1 in the conveyance direction of the document 1 (direction perpendicular to the reading width direction). The platen 13 is usually installed outside the image reading apparatus. The optical information of the irradiation unit 1 a of the document 1 near the focal plane of the rod lens array 8 is imaged on the light receiving surface of the sensor IC 9 as information on the convergence area of the rod lens array 8. In the drawings, the same reference numerals indicate the same or corresponding parts.

FIG. 2 is a development view of the image reading apparatus according to Embodiment 1 of the present invention. In FIG. 2, holders 14 are installed at both ends of the light guide 6 to fix or adjust the position and angle of the light guide 6. In addition, the holder 14 is fixed to the housing 5 and also plays a role in preventing foreign matters from being mixed. In order to install the LED board 3 having a width of 6 mm, the housing 5 is provided with two series of spaces having a width of 6.4 mm in the longitudinal direction. The LED board 3 is arranged from the end of the casing 5 along the longitudinal direction. Inserted, the back surface of the LED substrate 3 is fixed to the housing 5 with an adhesive. In the first embodiment, the light guide 6, the rod lens array 8, and the sensor IC 9 have a length equal to or greater than the effective reading width in the longitudinal direction of the document 1. In the figure, the same reference numerals as those in FIG. 1 denote the same or corresponding parts.

Next, the operation will be described with reference to FIGS. Light emitted from the light sources 2 arranged in an array on the LED substrate 3 toward the irradiation unit 1a is incident on the curved surface portion 6b of the light guide 6 installed in the reading width direction, and is collected by the curved surface portion 6b. , And passes through the light guide 6 as parallel light. The document 1 is irradiated with parallel light from a flat portion 6a provided at a position facing the curved surface portion 6b. Further, the exit surface of the exit-side curved surface portion 6c, which is outside the vicinity of the flat portion 6a, is refracted to irradiate the document 1. The reflected light reflected by the document 1 is converged by the rod lens array 8, and the light converged by the rod lens array 8 is received by the sensor IC 9 placed on the sensor substrate 10. The analog signal received and photoelectrically converted by the sensor IC 9 is subjected to digital signal processing by the ASIC 11, and a digital processing signal is sent from the external connector 12 to the system main body (not shown).

FIG. 3 is a plan view of a light source portion used in the lighting apparatus according to Embodiment 1 of the present invention. In FIG. 3, the light sources 2 using LEDs are arranged in an array linearly over the reading width, and an input terminal 3a for a power source constituted by a flexible substrate is installed at the end of the LED substrate 3, and the power source is Supplied to the LED. In the first embodiment, the LEDs are arranged in a bar shape. However, the light source may be an elongated flat light source configured in a bar shape using an organic light emitting material or the like.

FIG. 4 is a schematic cross-sectional view illustrating propagation of light incident on the light guide of the lighting apparatus according to Embodiment 1. Of the light emitted from the light source 2, the light that passes through the opening 4 a of the light limiting means 4 and directly enters the light guide 6 is condensed by the curved surface portion 6 b and converted into parallel light, and from the flat portion 6 a. Emitted. Light that does not directly enter the light guide 6 is scattered and reflected many times by the LED substrate 3, the light limiting means 4, and the housing 5 and then enters the light guide 6.

The width of the opening 4a of the light limiting means 4 is 2.5 mm, which is smaller than the diameter 4.0 mm of the cross section of the light guide 6. Further, the width of the flat portion 6a of the light guide 6 is set equal to or shorter than the width 2.5 mm of the opening 4a of the light limiting means 4. If the width of the flat portion 6a is made shorter than the width of the opening 4a of the light restricting means 4, a part of the light that becomes parallel light at the curved surface portion 6b reaches the exit-side curved surface portion 6c. However, the condensing property with respect to the irradiation part 1a improves.

As described above, according to the illumination device and the image reading device using the same according to the first embodiment, the width of the light incident on the light guide 6 is limited by the width of the opening 4a of the light limiting unit 4, and the flat portion By adjusting the irradiation width with 6a, there is an effect that the condensing property of light from the light source 2 and the illumination illuminance can be adjusted, and the illumination depth to the document 1 can be increased by the parallel light irradiated from the flat portion 6a.

Embodiment 2. FIG.
FIG. 5 is a schematic cross-sectional view for explaining the propagation of light incident on the light guide of the lighting apparatus according to Embodiment 2 of the present invention. In FIG. 5, the light guide 61 is a rod-like member extending in the longitudinal direction and serves as a light guide. In the second embodiment, a transparent light guide having a cross section of an aspherical surface is cut to provide a flat portion 61 a, and the light guide 61 includes an irradiation unit 1 a and a light source 2. There is a cross-sectional center of the light guide 61 on a line (irradiation axis) connecting the center position. The light that has passed through the light limiting means 4 is collected by the curved surface portion 61 b of the light guide 61 corresponding to the incident portion of the light guide 61, and parallel light is emitted from the flat portion 61 a of the light guide 61 facing the light guide 61. Further, when the width of the flat portion 61a is shorter than the width of the curved surface portion 61b corresponding to the width of the opening 4a, the light reaching the emission side curved surface portion (flat portion outside proximity portion) 61c is emitted from the emission side curved surface portion 61c. The light is refracted and irradiated to the irradiation unit 1a. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts. The light source 2, the light limiting unit 4, the light guide 61, and a part of the housing 5 that are placed on the LED substrate 3 are referred to as an illumination device.

Next, the operation will be described. Of the light emitted from the light source 2, the light that passes through the opening 4 a of the light limiting means 4 and directly enters the light guide 61 is condensed by the curved surface portion 61 b and converted into parallel light, and from the flat portion 61 a. Emitted. Light that does not directly enter the light guide 61 enters the light guide 61 after being scattered and reflected many times by the LED substrate 3, the light limiting means 4, and the housing 5.

The width of the opening 4a of the light limiting means 4 is 2.5 mm, which is smaller than the diameter 4.0 mm of the cross section of the light guide 61. Further, the width of the flat portion 61 a of the light guide 61 is set equal to or shorter than the width 2.5 mm of the opening 4 a of the light limiting means 4. If the width of the flat portion 6a is made shorter than the width of the opening 4a of the light restricting means 4, a part of the light that becomes parallel light at the curved surface portion 61b reaches the exit-side curved surface portion 6c. The light condensing property with respect to the part 1a is improved. The light limiting unit 4 may be integrated with the housing 5.

In Embodiment 2, the exit-side curved surface portion 61c of the light guide 61 is aspherical. Therefore, the condensing effect with respect to the light which does not pass through the flat part 61a can be made larger compared with the case where the light guide body 6 having a cut cylindrical shape described in the first embodiment is used.

As described above, according to the illumination device according to the second embodiment and the image reading device using the same, the width of the light incident on the light guide 61 is limited by the width of the opening 4a of the light limiting unit 4, and the flat portion By adjusting the irradiation width with 61a, there is an effect that the condensing property of light from the light source 2 and the illumination illuminance can be adjusted and the illumination depth with respect to the document 1 can be increased by the parallel light irradiated from the flat portion 61a. Furthermore, in the second embodiment, there is an advantage that the illuminance of illumination with respect to the effective irradiation width can be concentrated and irradiated by designing the emission side curved surface portion 61c to be aspherical.

Embodiment 3 FIG.
FIG. 6 is a schematic cross-sectional view illustrating the configuration of the illumination device according to the third embodiment. The light limiting means 41 is provided with a recess having a depth of 0.8 mm and a width of 5.2 mm, and a wavelength cut filter 30 having a thickness of 0.7 mm and a width of 5.0 mm is provided in the recess. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts. Since the configuration other than the light limiting unit 41 and the wavelength cut filter 30 is the same as that of the first embodiment, the description thereof is omitted. The light source 2 placed on the LED substrate 3, the light limiting means 41, the light guide 6 and a part of the housing 5 are collectively referred to as a lighting device.

The wavelength cut filter 30 limits the wavelength of part of the light that passes through the opening 41 a of the light limiting unit 41 and enters the light guide 6. Therefore, it becomes possible to select only the light of a required wavelength and irradiate the irradiation part 1a. In the third embodiment, only the light having the required wavelength is selected to irradiate the irradiation unit 1a. However, when only the light having the required wavelength is selected, a wavelength pass filter is used. You may make it irradiate the irradiation part 1a. The light limiting means 41 may be integrated with the housing 5.

As described above, according to the third embodiment, the light wavelength cut filter 30 or the wavelength pass filter is added between the light source 2 and the light guide 6 to irradiate light having an unnecessary wavelength emitted from the light source 2. Can be prevented.

Embodiment 4 FIG.
FIG. 7 is a cross-sectional configuration diagram of an image reading apparatus according to Embodiment 4 of the present invention. In FIG. 7, the light limiting means 42 is made of resin or metal having a region for placing the light guide 6 with a certain width along the longitudinal direction. The light guide 6 is a rod-shaped member extending in the longitudinal direction and serves as a light guide. In this Embodiment 4, the thing of the shape which cut | disconnected some cylindrical light guides and provided the flat part 6a is used, and the light guide 6 is the center position of the irradiation part 1a and the light source 2 There is a cross-sectional center of the light guide 6 on the line (irradiation axis) connecting the two. The flat portion 6a of the light guide 6 is installed so as to be orthogonal to the irradiation axis. The light that has passed through the light limiting means 42 is collected by the curved surface portion 6 b of the light guide 6 corresponding to the incident portion of the light guide 6, and parallel light is emitted from the flat portion 6 a of the light guide 6 facing the light guide 6. Further, when the width of the flat portion 6a is shorter than the width of the curved surface portion 6b, the light reaching the emission side curved surface portion (flat portion outside proximity portion) 6c is refracted by the emission side curved surface portion 6c and irradiated to the irradiation unit 1a. Is done. The light guide 6 is a cylindrical portion cut to form a flat portion 6a. If the flat portion 6a is flat, a rod-shaped light guide 6 having an elliptical cross section or a spindle cross section is used. Also good.

Next, a light-shielding film (light-shielding member) 6d obtained by applying or vapor-depositing a light-shielding resin to the light guide 6 is formed on the light guide 6 along the longitudinal direction of the light guide 6. The light incident on the curved surface portion 6b of the light body 6 is limited. The width (W1) of the curved surface portion 6b corresponds to the slit width of the light shielding film 6d provided on both sides of the light guide 6 on the incident side. That is, it corresponds to the width of the opening 42 a provided in the light guide 6. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts. The light source 2, the light limiting means 42, the light guide 6, and a part of the housing 51 that are placed on the LED substrate 3 are referred to as a lighting device. Other configurations and operations are the same as those described in the first embodiment, and thus description thereof is omitted.

From the above, in Embodiments 1 to 3, the curved surface portions 6b and 61b of the light guides 6 and 61 are provided on the light guides 6 and 61 side of the light limiting means 4 and 41, but in Embodiment 4, Since the curved surface portion 6b is arranged close to the light source 2 side, there is an advantage that the parallel light emitted from the flat portion 6a is increased and the illuminance emitted by the parallel light component is improved.

As shown in FIG. 8, instead of the wavelength cut filter 30 described in the third embodiment, filters 31 using a resin layer or a thin plate for cutting a specific wavelength are provided on both sides on the incident side of the light guide 6. By applying (evaporating) or pasting to the slit of the light shielding film 6d, an effect equivalent to that described in the third embodiment is obtained for a specific wavelength.

Embodiment 5 FIG.
FIG. 9 is a cross-sectional configuration diagram of an image reading apparatus according to Embodiment 5 of the present invention. In FIG. 9, the light limiting means 43 is made of a light-shielding resin or metal provided with an opening (slit portion) having a certain width along the longitudinal direction. Only the light emitted from the light source 2 that has passed through the opening 43a of the light limiting means 43 is taken out, and the other components are scattered and reflected in the space surrounded by the LED substrate 3, the light limiting means 43, and the casing 52. After that, the light passes through the opening 43a of the light limiting means 43 and is taken out. Therefore, the light extraction efficiency is improved by increasing the reflectance, for example, the surface of the LED substrate 3, the bottom surface of the light limiting unit 43, and the inner surface of the housing 52 are white. The light limiting unit 43 may be integrated with the housing 52.

The light guide 6 is a rod-shaped member extending in the longitudinal direction and serves as a light guide. In this Embodiment 5, the thing of the shape which cut | disconnected some cylindrical light guides and provided the flat part 6a is used, and the light guide 6 is the center position of the irradiation part 1a and the light source 2 There is a cross-sectional center of the light guide 6 on the line (irradiation axis) connecting the two. The flat portion 6a of the light guide 6 is installed so as to be orthogonal to the irradiation axis. The light that has passed through the light limiting means 43 is collected by the curved surface portion 6 b of the light guide 6 corresponding to the incident portion of the light guide 6, and parallel light is emitted from the flat portion 6 a of the light guide 6 facing the light guide 6. Further, when the width of the flat portion 6a is shorter than the width of the curved surface portion 6b, the light reaching the emission side curved surface portion (flat portion outside proximity portion) 6c is refracted by the emission side curved surface portion 6c and irradiated to the irradiation portion 1a. Is done. The light guide 6 was cut into a cylindrical shape to form a flat portion 6a. If the flat portion 6a is flat, a rod-shaped light guide 6 having an elliptical cross section and a spindle cross section is used. Also good. In the figure, the same reference numerals as those in FIG. 4 denote the same or corresponding parts. The light source 2, the light limiting unit 43, the light guide 6, and a part of the casing 52 placed on the LED substrate 3 are referred to as an illumination device. Other configurations and operations are the same as those described in the first embodiment, and thus description thereof is omitted.

In the fifth embodiment, a part of the casing 52 that fixes the light guide 6 is separated from the light restricting means 43, and a space region is provided between the light restricting means 43 and the light guide 6. Then, the light that enters the light guide 6 is limited by the opening 43 a of the light limiting means 43. That is, the width (W1) of the curved surface portion 6b corresponds to the opening 43a of the light limiting means 43 provided on the incident side of the light guide 6.

As described above, in the fifth embodiment, the distance between the curved surface portion 6b and the light source 2 is arranged farther than that described in the fourth embodiment, but the light limiting means 43 and the curved surface portion 6b of the light guide 6 are arranged. Has an advantage that the illuminance of the emitted parallel light is stabilized.

Further, as shown in FIG. 10, the wavelength cut filter 30 described in the third embodiment is attached to the light restricting unit 43 in a spatial region located between the light restricting unit 43 and the light guide 6 and specified. The same effects as those described in the third embodiment can be obtained with respect to the wavelength.

In addition, in the said Embodiment 1-5, it is also possible to use in combination with each other, and there can exist an effect similar to each effect in each embodiment.

1..Subject to be irradiated (original) 1a..Irradiation part 2..Light source 3..LED substrate 3a..Substrate (flexible substrate)
4. ・ Light limiting means 4a ・ ・ Slit (opening) 5 ・ ・ Case 6 ・ ・ Light guide 6a ・ ・ Flat portion 6b ・ ・ Curved surface 6c ・ ・ Exit-side curved surface 6d ・ ・ Light shielding member (light shielding) film)
7 .. Transmitter 8 .. Rod lens array (lens body)
9. ・ Light receiving part (sensor IC) 10. ・ Sensor board 11. ・ Signal processing IC (ASIC)
12. ・ Connector (external connector) 13. ・ Platen (conveying means)
14..Holder 30..Wavelength cut filter 31..Wavelength cut filter 41..Light limiting means 41a..Slit (opening)
42..Light limiting means 42a..Slit (opening)
43..Light limiting means 43a..Slit (opening)
51..Case 52..Case 61..Light guide 61a..Flat part 61b..Curved surface 61c..Output side curved surface

Claims (10)

A light source for irradiating light to the irradiating part of the document over the reading width and an irradiation axis connecting the light source and the irradiating part are arranged, and the light of the light source is condensed on the curved surface part to be parallel light. A light guide that irradiates light from a flat portion provided at a position facing the curved surface portion, a slit portion at a position corresponding to the irradiation axis by shielding the surroundings, and reading light incident on the curved surface portion A light restricting means for restricting the light, and the light source reaching the light restricting means is surrounded by at least the direction of the irradiation portion of the irradiation axis and the light source is placed, and the light guide and the light limiting A lighting device comprising a housing for storing or holding the means. The width of the flat part of the light guide is made shorter than the width of the slit part of the light restricting means, and the parallel light from the flat part of the light guide and the refracted light from the outside of the flat part of the light guide to the irradiation part The illumination device according to claim 1 irradiating. The lighting device according to claim 1, wherein the light limiting unit is a light shielding resin layer applied or deposited on a curved surface portion of the light guide. The lighting device according to claim 1, wherein the light limiting unit is provided with a long groove in the casing to form the slit portion, and the periphery of the long groove is shielded by a part of the casing. The lighting device according to any one of claims 1 to 4, wherein an optical filter that blocks or passes a predetermined optical wavelength is installed between the curved surface portion of the light guide or the light source and the light guide. A light source for irradiating light to the irradiating part of the document over the reading width, arranged on the irradiation axis connecting the light source and the irradiating part, and condensing the light of the light source on the curved surface part to make parallel light. A light guide that emits light from a flat portion provided at a position facing the curved surface portion, and a light that enters the curved surface portion provided with a slit portion at a position corresponding to the irradiation axis while shielding the surrounding area over a reading width The light limiting means for limiting the light, the light of the light source reaching the light limiting means is surrounded at least except for the direction of the irradiation portion of the irradiation axis, the light source is placed, and the light guide and the light limiting means are accommodated An image reading apparatus comprising: an illuminating device having a housing for holding; a lens body that converges light reflected by the document; and a light receiving unit that receives light converged by the lens body. The width of the flat part of the light guide is made shorter than the width of the slit part of the light restricting means, and the parallel light from the flat part of the light guide and the refracted light from the outside of the flat part of the light guide to the irradiation part The image reading apparatus according to claim 6 irradiating. The image reading apparatus according to claim 6, wherein the light limiting unit is a light shielding resin layer applied or deposited on a curved surface portion of the light guide. The image reading apparatus according to claim 6, wherein the light limiting unit is provided with a long groove in the housing to form the slit portion, and the periphery of the long groove is shielded by a part of the housing. The image reading apparatus according to claim 6, wherein an optical filter that blocks or passes a predetermined optical wavelength is installed between the curved surface portion of the light guide or the light source and the light guide.

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