JPH1155456A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the manufacturing cost of an image reader in which mount of a prescribed component such as a light source being a component of the image reader and electric wiring or the like are easily conducted without causing any defect on the image read function or the like. SOLUTION: The reader is provided with a printed circuit board 6 on which a plurality of light receiving elements 52 are mounted, a light guide member 1 and a light source 2. The light source 2 is mounted on a face in common to a face on which a plurality of the light receiving elements 52 of the printed circuit board 6 are mounted. Part of a 2nd side face 10B of the light guide member 1 is placed opposite to the light source 2 and the light made incident from the part of the 2nd side face 10B on the light guide member 1 is reflected in a plurality of side faces 10A-10D so as to be emitted externally from the entire area or nearly the entire area of the 1st side face 10A while being propagated in the lengthwise direction of the light guide member 1. Then the entire face or the part face of the 3rd side face 10C is tilted opposite to the 2nd side face 10B so that the light propagated in the broadwise direction of the light guide member 1 from the direction of the 2nd side face 10B is reflected in a direction toward the image read area S via the 1st side face 10A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus such as a contact type image sensor and a flat bed type image sensor.

[0002]

2. Description of the Related Art Conventionally, as an image reading apparatus of this type, there is one disclosed in Japanese Patent Application Laid-Open No. 6-217084, for example. This conventional device uses a linear light source device B as shown in FIG.
Light can be applied to a predetermined image reading area 90 on the surface of the document placing plate 91 mounted on the upper surface of the document. As shown in FIG. 19, the linear light source device B includes a light guide member 1e made of a transparent member having a certain length.
And a light source 2e opposed to an end face 15e at the longitudinal end of the light guide member 1e. Light guide member 1
e has a first side surface extending in the longitudinal direction as the light emitting surface 12e.
In addition, substantially the entirety of the second side surface facing the light emitting surface 12e in the thickness direction is a light diffuse reflection surface 14e, and the light emitted from the light source 2e passes through the end surface 15e and is a light guide member. When the light enters the inside of the light guide member 1e, the light travels in the longitudinal direction of the light guide member 1e and exits from various parts of the light exit surface 12e to the outside.

According to the image reading apparatus having the above-described structure, light can be emitted from the entire or substantially entire area of the light exit surface 12e having a fixed length of the light guide member 1e. On the other hand, it is possible to irradiate light linearly or in a band. Therefore, the original K
Can be read line by line using the lens 51e and the plurality of light receiving elements 52e. Further, the linear light source device B is configured to cause the light emitted from the point light source 2e to travel in the longitudinal direction of the light guide member 1e and to emit the light from various parts of the light guide member 1e. The number can be small or minimal, eg LE
The necessity of arranging a large number of light sources such as D at predetermined intervals in the image reading line direction can be eliminated.

[0004]

However, the above-mentioned conventional image reading apparatus has the following disadvantages.

That is, in the above-described conventional image reading apparatus, the light source 2e is connected to the end surface 15 of the light guide member 1e in the longitudinal direction.
e, the longitudinal direction of the light guide member 1e must be set to a predetermined image reading line direction. Therefore, conventionally, as means for disposing the light source 2e to face the end face 15e of the light guide member 1e, means for mounting the light source 2e on a circuit board 6e on which a plurality of light receiving elements 52e are mounted is employed. The light source 2e must be mounted on a dedicated board 92 separate from the circuit board 6e.
However, if such a means is adopted, the entire linear light source device B is assembled in the case 4e almost completely independent of the circuit board 6e. This not only complicates the overall positioning structure of the linear light source device B in the case 4e, but also makes the light receiving element 5
The respective electric wiring systems of the light source 2e and the light source 2e must also be separately manufactured. Further, regarding the light source 2e,
Since the positioning accuracy is also required in relation to the light guide member 1e, the structure of the peripheral portion related to the light source 2e becomes more complicated. Therefore, in the related art, the manufacturing operation of the image reading apparatus has been complicated, and the manufacturing cost has been high.

The present invention has been conceived in view of such circumstances, and assembles predetermined components such as a light source constituting an image reading apparatus without causing a problem in an image reading function. It is an object of the present invention to facilitate operations and electrical wiring operations, thereby reducing the manufacturing cost of an image reading apparatus.

[0007]

DISCLOSURE OF THE INVENTION In order to solve the above problems, the present invention employs the following technical means.

According to the present invention, a plurality of light receiving elements arranged in a row in an image reading line direction so as to be able to receive light traveling from a predetermined image reading area, and a circuit mounting the plurality of light receiving elements A substrate and a light guide member made of a transparent member having a fixed length disposed on one side of an optical path from the image reading area to the plurality of light receiving elements,
A light source, and the light guide member has a plurality of side surfaces extending in the image reading line direction, a first side surface and a second side surface separated in a thickness direction of the light guide member, and a width of the light guide member. An image reading device having a third side surface and a fourth side surface separated from each other in a direction, wherein the light source is mounted on a common surface of the circuit board on which the plurality of light receiving elements are mounted. And the light guide member is disposed such that a part of the second side surface faces the light source,
Light that has entered the light guide member from a portion of the second side surface is reflected by the plurality of side surfaces, so that the light travels in the longitudinal direction of the light guide member, and from the entire area or substantially the entire area of the first side surface to the outside. It is formed to emit light,
And the whole or a part of the third side surface of the light guide member,
The inclined surface is opposed to the second side surface so that light traveling in the thickness direction of the light guide member from the direction of the second side surface can be reflected in a direction toward the image reading area via the first side surface. It is characterized by:

[0009] The inclined surface of the third side surface may be a plane, a curved surface, or a surface in which a plurality of planes having different angles stepwise are connected in series. The light source emits white light or monochromatic light of any other color.
ED light source or LED emitting light of each color of R, G, B
Can be configured to be an LED light source combining the above. Further, the light source may be an LED chip directly bonded on the circuit board.

In the present invention, since the light source and the plurality of light receiving elements are mounted on a common surface of the same circuit board, the light source is mounted on a separate board from the circuit board on which the light receiving element is mounted. As compared with the conventional one, the assembling work and the positioning work of the light source can be remarkably facilitated. Further, the electric wiring system of the light source can be formed on a circuit board in the same manner as the electric wiring system of the light receiving element, and the patterns can be formed at the same time. Becomes

On the other hand, according to the present invention, when the light source mounted on the circuit board emits light, the light enters the light guide member from a portion of the second side surface of the light guide member, and the light guide member includes a plurality of light guide members. By repeating the reflection by the side surface, the light is emitted from the entire or substantially the entire first side surface of the light guide member while traveling in the longitudinal direction. In this case, among the light traveling inside the light guide member, there is light that travels in the thickness direction of the light guide member and reaches the third side surface by being reflected by the second side surface. By reflecting the light by the inclined surface of the third side surface, the light can be made to travel in a direction approaching the image reading area and then emitted from the first side surface. Further, the entire surface or a part of the third side surface of the light guide member may be formed as an inclined surface, so that the first side surface can be substantially closer to the image reading area than the second side surface. Thus, the image reading area can be effectively irradiated with light from the vicinity thereof. That is, the light guide member is disposed on one side of the optical path from the image reading area to the light receiving element, and the second
Although the side faces the light source mounted on the circuit board on which the light receiving element is mounted, in the present invention, the entire or a part of the third side of the light guide member is a predetermined inclined surface, Most of the light emitted from the first side surface can be emitted toward the image reading area. Therefore, even when the light source is mounted on the circuit board on which the light receiving element is mounted, it is possible to prevent a problem that the light emitted from the light source cannot be appropriately applied to a predetermined image reading area by the light guide member. be able to.
As described above, in the present invention, it is possible to easily perform a light source assembling operation, an electric wiring operation, and the like without causing a problem in a light irradiation operation on the image reading region.
A favorable effect that the manufacturing cost of the image reading device can be reduced can be obtained.

[0012] In a preferred embodiment of the present invention, the entire or a part of the fourth side surface is an inclined surface inclined in the same direction as the inclined surface of the third side surface, and the first side surface is the same as the inclined surface. It is possible to adopt a configuration in which it is arranged so as to be biased in a direction approaching the image reading area rather than two side faces.

According to such a configuration, the first side surface of the light guide member for irradiating light toward the image reading area is formed by:
The image reading region can be made closer to the image reading region than the second side surface, and the light irradiation efficiency to the image reading region can be further increased.

In another preferred embodiment of the present invention,
The outer surface of the light guide member may be configured such that all or part of a region excluding a part of the second side surface facing the light source and the first side surface is covered with a light reflecting member. .

According to such a configuration, the outer surface of the light guide member other than those described above does not cause a problem in the incidence of light from the light source into the light guide member or the operation of emitting light from the first side surface. Leakage of light from the portion to the outside can be appropriately prevented by the light reflecting action of the light reflecting member. Therefore, light loss can be reduced, and the efficiency of irradiating a predetermined image reading area can be further increased.

In another preferred embodiment of the present invention,
The light reflecting member may be a member that scatters and reflects the received light.

According to such a configuration, when the light travels in the longitudinal direction of the light guide member, the light is scattered and reflected by the light reflection member, for example, the first side surface of the light guide member. It is possible to suppress the light from being intensively emitted to the outside from only a part, and to make uniform the illuminance at various points in the image reading line direction of the image reading area.

In another preferred embodiment of the present invention,
A longitudinal end portion of the second side surface of the light guide member is a light incident portion facing the light source, and a position of the first side surface facing the light incident portion is the light incident portion. The light guide member may have a configuration in which an inclined surface is provided that reflects the light that has entered the light guide member toward the center in the longitudinal direction of the light guide member.

According to such a configuration, the light emitted from the light source enters the light guide member from the light incident portion at the longitudinal end of the second side surface of the light guide member, and is incident on the inclined surface of the first side surface. When the light reaches the light guide member, the light is reflected toward the longitudinal center portion of the light guide member and travels in the longitudinal direction of the light guide member. Therefore, light can be appropriately emitted from the entire or substantially the entire first side surface of the light guide member.

In another preferred embodiment of the present invention,
An intermediate portion in the longitudinal direction of the second side surface of the light guide member is a light incident portion facing the light source, and a position facing the light incident portion of the first side surface is the light incident portion from the light incident portion. The light guide member may be provided with a concave portion having a substantially V-shaped cross section and having two inclined surfaces for reflecting the light incident into the light guide member toward both ends in the longitudinal direction of the light guide member.

According to this structure, the light emitted from the light source enters the light guide member from the light incident portion at the longitudinally intermediate portion of the second side surface of the light guide member, and the two inclined surfaces of the first side surface are inclined. When the light reaches each of the surfaces, the light is reflected toward both ends in the longitudinal direction of the light guide member, and travels in the longitudinal direction of the light guide member. Therefore, light can be appropriately emitted from the entire or substantially the entire first side surface of the light guide member.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be specifically described below with reference to the drawings.

The structure of the light guide member used in the image reading apparatus of the present embodiment is different from that of the conventional light guide member. Therefore, the structure of the light guide member will be described first for convenience.

FIG. 1 is a partially cutaway perspective view showing an example of a light guide member applied to the image reading apparatus according to the present invention. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3 shows FIG.
FIG. 3 is a sectional view taken along line III-III of FIG.

The light guide member 1 shown in these figures includes a transparent member 10 obtained by molding an acrylic transparent resin such as PMMA. This transparent member 10 is in the form of an elongated bar having a certain dimension in the longitudinal direction. The outer surface of the transparent member 10 includes the transparent member 1
0, the first side surface 10A and the second side surface 10 extending in the longitudinal direction.
B, a third side surface 10C, a fourth side surface 10D, and end surfaces 10E and 10F at both ends in the longitudinal direction. An inclined surface 16 is provided at one end of the first side surface 10A in the longitudinal direction. As is clearly shown in FIG. 3, the first side surface 10A and the second side surface 10B are separated in the vertical thickness direction of the transparent member 10 and are surfaces that are substantially parallel to each other. The first side surface 10A is formed narrower than the second side surface 10B.

The third side face 10C and the fourth side face 10D are opposed to each other at a distance in the width direction of the transparent member 10. The third side surface 10C has an inclined surface portion 11 and a non-inclined surface portion 12, and strictly speaking, the transparent member 10
It has a pentagonal cross section. The non-inclined surface portion 12 is a surface substantially orthogonal to the second side surface 10B. In contrast,
The inclined surface portion 11 is inclined with respect to the second side surface 10B so as to face the second side surface 10B. The fourth side surface 10D is formed as an inclined surface whose substantially entire area is inclined in the same direction as the inclined surface portion 11. As described above, in the light guide member 1, the inclined surface portion 11 is formed on the third side surface 10C, and the fourth side surface 10D is formed as the inclined surface in the same direction as the inclined surface portion 11C.
Is formed in a shape deviated by an appropriate dimension L from the one side edge of the second side surface 10B toward the side on which the fourth side surface 10D of the transparent member 10 is formed.

The first side surface 10A is a portion where the entire surface or almost the entire surface excluding the inclined surface 16 is a light emitting surface, and is preferably a mirror-like flat surface. Similarly,
The third side surface 10C and the fourth side surface 10D are also mirror-like planes. The mirror-like surface does not necessarily need to be a surface whose surface is actively polished. For example, when a transparent member is resin-molded using a mold, a relatively smooth surface obtained by the resin molding is also included in the mirror-like surface. If the surface of the transparent member has a mirror-like shape, when light travels inside the transparent member, light rays incident on the surface at an angle larger than the critical angle for total reflection specified by the material of the transparent member are referred to. Light rays that can be totally reflected and incident at an angle smaller than the critical angle for total reflection can be transmitted to the outside.

As is clearly shown in FIG. 2, one end of the second side surface 10B in the longitudinal direction is a light incident portion 15. The light incident portion 15 is a portion for causing light emitted from the light source 2 described later to enter the transparent member 10.
Preferably, it is a mirror-like plane. The inclined surface 16
Is opposed to the light incident portion 15 and the light incident portion 1
The light incident from 5 on the transparent member 10 in the thickness direction (upward) is inclined so as to be able to be reflected toward the other end of the transparent member 10 in the longitudinal direction. In the present invention, instead of forming the inclined surface 16 in a planar shape, the inclined surface 16 may be formed as, for example, a curved surface, or a surface in which a plane and a curved surface are connected in series. The outer surfaces of the inclined surface 16 and the end surface 10F are covered with a light reflecting member 17 having a high light reflectance, and a part of the light reaching the inclined surface 16 and the end surface 10F is transmitted to the outside of the transparent member 10 as it is. It is formed not to be. As another means for preventing light from passing through the inclined surface 16 and the end face 10F and leaking to the outside of the transparent member 10, a paint having a high light reflectance or another light reflecting material is applied. Means for attaching to the outer surface of the inclined surface 16 by plating, vapor deposition, sputtering or the like may be adopted.

A plurality of recesses 14 are provided at appropriate intervals in a region of the second side surface 10B other than the light incident portion 15. The region between the plurality of recesses 14 is a mirror-like flat portion 13. The recesses 14 increase the possibility that the angle of incidence of light on the first side surface 10A becomes smaller than a predetermined critical angle for total reflection by rapidly changing the traveling angle of light traveling inside the transparent member 10. , First
It is a part that plays a role of emitting light from various parts of the side surface 10A. Each of the concave portions 14 has, for example, an arc-shaped cross section.

As means for reflecting the light incident on the second side face 10B in the form of scattered reflection or near scattered reflection, for example, instead of the means for providing the plurality of recesses 14 on the second side face 10B, Means for forming a plurality of convex portions, means for providing a rough surface portion having minute irregularities on the second side surface, coating with a paint or other substance capable of scattering and reflecting light,
Various means, such as a means for attaching to the second side surface by plating, vapor deposition, sputtering, or the like, and a means for bringing a member capable of scattering and reflecting light into contact with the second side surface, can be adopted.

The light guide member 1 plays a role of causing the light incident on the light guide member 1 from the light incident portion 15 of the second side surface 10B to be emitted from the entire or substantially entire surface of the first side surface 10A. Specifically, as shown in FIG. 2, light emitted from the light source 2 disposed opposite the light receiving surface is incident from the light incident portion 15 into one longitudinal end of the light guide member 1 at an appropriate spread angle. Most of the light is reflected by the inclined surface 16 toward the other end of the light guide member 1 in the longitudinal direction. Then, the light is transmitted to the first side surface 10A, the second side surface 10B, and the third side surface 10A.
The light reaches the end face 10E at one end in the longitudinal direction of the light guide member 1 while repeating reflection at each of the side face 10C and the fourth side face 10D. When light is incident on the second side surface 10B, most of the light incident on each concave portion 14 is reflected in a form close to scattered reflection, and the course of the light is rapidly changed.
Therefore, the possibility that the light that has reached the second side surface 10B is incident on the first side surface 10A at an incident angle smaller than a predetermined critical angle for total reflection is increased.

However, since the inclined surface portion 11 of the third side surface 10C is opposed to the second side surface 10B, the light is reflected by the second side surface 10B and then proceeds in the thickness direction of the light guide member 1. Most of the light reaches the inclined surface portion 11. Then, the light is caused by the inclined surface portion 11 to be closer to the fourth side surface 1 than the incident position on the inclined surface portion 11.
The light is reflected in a direction closer to 0D and is emitted directly from the first side surface 10A to the outside, or is emitted to the outside after being reflected by the fourth side surface 10D and reaching the first side surface 10A. Therefore, light tends to be emitted from the first side surface 10A in a direction inclined with respect to the thickness direction of the light guide member 1 (the direction of arrow N in FIG. 3).

FIG. 4 is a partially omitted sectional view showing an example of the image reading apparatus according to the present invention. FIG. 5 shows V in FIG.
It is -V sectional drawing. FIG. 6 is a sectional view taken along line VI-VI of FIG. FIG. 7 is an exploded perspective view of the image reading device shown in FIG.

The image reading device A shown in these figures
7, the case 4, the circuit board 6,
The plurality of light receiving elements 52 mounted on the circuit board 6, the light source 2, the condenser lens 51, the first light reflecting member 3A,
The second light reflecting member 3 </ b> B, one or more attachments 69, and the above-described light guide member 1 are provided. This image reading device A is configured as a flatbed type image sensor, and is shown in FIGS.
As shown in FIG. 1, a document placing plate 70 made of transparent glass is provided on the upper surface of which a guide surface 71 for placing an image reading object such as a document K to face is provided.

The case 4 is made of, for example, a synthetic resin, and is formed in an elongated box shape having an opening at substantially the entire upper surface and an opening at the bottom as appropriate. The main components of the image reading apparatus A described above are accommodated in the case 4. The case 4 is provided below the document placing plate 70 so as to be movable in the image reading sub-scanning direction relative to the document placing plate 70. Means for making the case 4 movable are conventionally known, and therefore description thereof is omitted.

Each of the first light reflecting member 3A and the second light reflecting member 3B is formed in an elongated bar shape or a plate shape having substantially the same length as the light guide member 1.
These two light reflecting members 3A and 3B are shown in FIGS.
The light guide member 1 is formed so as to be sandwiched from both sides in the width direction, and the light guide member 1 is sandwiched between the two light reflection members 3A and 3B. , Above the circuit board 6 in the case 4. The two light reflecting members 3A and 3B fit into a predetermined space in the case 4 and also serve to position and fix the light guide member 1 in the case 4. However, the light guide member 1 is a case. 4, the light incident portion 15 is positioned so as to approach and face the upper surface (light emitting surface) of the light source 2 mounted on the upper surface of the circuit board 6. The light guide member 1 is disposed on one side of a series of optical paths extending from the image reading area S to the plurality of light receiving elements 52 via the optical lens 51.
The first side surface 10A is set to be substantially closer to the optical path than the side surface 10B.

The first light reflecting member 3A has side surfaces 30b and 30d that come into contact with the second side surface 10B and the fourth side surface 10D of the light guide member 1, and the second light reflecting member 3A. 3B has a side surface 30c that comes into contact with the third side surface 10C of the light guide member 1, and these side surfaces 3c.
Ob to 30d serve to prevent the light that has entered the light guide member 1 from passing through the side surfaces 10B to 10D and leaking to the outside. Of course, the vicinity of the light incident portion 15 at one end in the longitudinal direction of the third side surface 10C or the fourth side surface 10D is also covered by the side surfaces 30c and 30d. However, the side surface 30b is not provided at a position facing the light incident portion 15 as is well shown in FIG. 6, and the light emitted from the light source 2 is appropriately incident on the light incident portion 15. It is supposed to. As shown in FIG. 4, a flat side surface 30e is provided at one end of the first light reflecting member 3A in the longitudinal direction, and the side surface 30e is connected to the end surface 10E of the light guiding member 1. Are arranged to face each other. Therefore, when the light traveling inside the light guide member 1 reaches the end face 10E, the light is surely reflected by the side face 30e, preventing the light from leaking to the outside from the end face 10E. Is done. The first light reflecting member 3A and the second light reflecting member 3
Each of B is made of, for example, a white synthetic resin,
The side surfaces 30b to 30e are surfaces having high light reflectance. In the present embodiment, these side surfaces 30b to 30e are light scattering reflection surfaces that scatter and reflect the received light in various directions.

As means for holding the light guide member 1 on the first light reflecting member 3A or the second light reflecting member 3B, for example, means shown in FIG. 8 can be adopted. The means shown in FIG. 1 is provided with holes 39a and 39b at appropriate positions on the side surface of the light guide member 1 so that the light guide member 1 can be connected to the first light reflection member 3A and the second light reflection member. This is a means for fitting the projections 38a, 38b provided on the side portions of the holes 39a, 39b into the holes 39a, 39b. According to such means, the light guide member 1 is reliably positioned with respect to the two light reflection members 3A, 3B by the fitting action of the holes 39a, 39b and the projections 38a, 38b, and the light guide member It can be made more preferable in preventing the position 1 from being displaced in the case 4. Further, the light guide member 1 and the two light reflection members 3
A and 3B can be held in a state where they are assembled as a unit, and the advantage of facilitating the work of assembling these components into the case 4 is also obtained. When assembling the light guide member and the light reflection member using holes or protrusions,
Contrary to the above configuration, a projection is provided on the light guide member,
The light reflecting member may be provided with a hole.

As best shown in FIG. 5, the condenser lens 51 is disposed below the original placing plate 70 so as to face a predetermined image reading area S. The condenser lens 51 illuminates the image reading area S and reflects the light reflected by the area S to a plurality of light receiving elements 52.
For example, a lens array in which a plurality of selfoc lenses (rod lenses) capable of focusing an image of an original K at an erect equal size is arranged in an image reading line direction (main scanning direction) is applied. Is done. Of course, a lens array in which convex lenses are arranged in series may be used instead. The plurality of light receiving elements 52 receive the light converged by the condenser lens 51 and perform photoelectric conversion of the light. The plurality of light receiving elements 52 are arranged in a row extending in the image reading line direction, and are arranged on the surface of the circuit board 6. Has been implemented.

As the light source 2, for example, an LED light source in which an LED chip is resin-packaged is used. The light source 2 is mounted on the surface of one end of the circuit board 6 in the longitudinal direction so as to face the light receiving surface 15 of the light guide member 1. When the image reading apparatus A is used for reading a so-called monochrome image, the light source 2 may be a light source that emits monochromatic light of white or other colors. , Three types of LEDs that emit light of each color of R, G, and B (red, green, and blue) or an LED that emits white light are used. Three types of LED
In the case of using the LED, a light source in which these three LED chips are packaged in one package can be provided. In the present invention, an LED chip without a resin package may be used as a light source, and means for directly bonding this LED chip to the surface of the circuit board 6 may be employed. If such a means is adopted, the cost of parts can be made lower than a means using a light source in which an LED chip is resin-packaged.

The circuit board 6 is made of, for example, epoxy resin or ceramics, and has on its surface a conductive wiring pattern (not shown) for mounting the light receiving elements 52 and the light source 2. ing. As shown in FIG. 7, a connector terminal 65 is attached to the other end of the circuit board 6 in the longitudinal direction. If the connector terminal 65 is attached to the end of the circuit board 6 opposite to the mounting position of the light source 2, it is advantageous in securing a mounting space for the light source 2 on the circuit board 6. When an external control device (not shown) is connected to the connector terminal 65 by wiring, the light receiving element 52 and the light source 2 can be electrically connected to the external control device. Needless to say, the case 4 is appropriately provided with a space (not shown) for avoiding interference with the connector terminal 65.

The circuit board 6 is fitted into a recess 49 provided at the bottom of the case 4 from below the case 4. The attachment 69 is for attaching the circuit board 6 to the case 4, and is externally fitted to the case 4 from below, and the engagement projections 48, 48 provided on the left and right outer surfaces of the case 4. The circuit board 6 is prevented from dropping downward. The attachment 69 is formed by, for example, pressing a thin metal plate, and exhibits appropriate elasticity.

Next, the operation when an image reading operation is performed using the image reading apparatus A will be described.

First, when the light source 2 is caused to emit light in a state where the document K is placed on the document placing plate 70, light is emitted from the light source 2 upward, and the light incident on the light guide member 1 is incident. The light enters the portion 15 upward. Then, the light reaches the inclined surface 16 and is reflected, and proceeds toward the other longitudinal end of the light guide member 1. As described above, the light guide member 1 causes the light traveling in the longitudinal direction to be reflected by the concave portion 14 of the second side surface 10B in a form close to scattered reflection, thereby emitting the light from various parts of the first side surface 10A. Of the light scattered and reflected by the second side surface 10B, most of the light is reflected by the inclined surface portion 11 of the third side surface 10C in the direction of the fourth side surface 10D, in other words, in the direction approaching the image reading area S. And then the first side 10A
Out to the outside. Moreover, the first side surface 10A is
It is biased in the width direction of the light guide member 1 with respect to the second side surface 10B, and is closer to the image reading area S than the second side surface 10B. Therefore, the light emitted from the first side surface 10A can be appropriately and efficiently applied to the image reading area S. When the illuminance of the image reading area S decreases, the quality of the read image deteriorates. However, the image reading device A can prevent such a problem from occurring.

Particularly, in the present embodiment, the light incident portion 15 and the first side surface 10 of the transparent member 10 constituting the light guide member 1
Since parts other than A are covered with the light reflecting members 17, 3A, 3B, light leakage to the outside of the light guide member 1 can be eliminated or reduced, and the image reading area S
Can be further improved in light irradiation efficiency. Third
First light reflecting member 3 surrounding side surface 10C and fourth side surface 10D
A and the side surfaces 30c and 30d of the second light reflecting member 3B are incident on the third side surface 10C and the fourth side surface 10D at an angle smaller than a predetermined critical angle for total reflection.
C and 10D are scattered and reflected, and the light arriving at the third side surface 10C and the fourth side surface 10D is scattered and reflected, thereby forming the first side surface 10C.
Light can easily reach all the points A, which is preferable in achieving a uniform light amount distribution of light emitted from the first side surface 10A.

FIG. 9 is a sectional view showing another example of the image reading apparatus according to the present invention. In the drawings after FIG. 9, the same parts as those in the above embodiment are denoted by the same reference numerals,
The description is omitted for convenience.

The image reading device Aa shown in FIG. 9 is configured as a contact image sensor. This image reading device Aa has the same basic configuration as the image reading device A of the previous embodiment, but the upper surface of the case 4a has an original made of transparent glass for arranging the original K opposite thereto. The mounting plate 70a is mounted. A platen roller 98 for transporting the document K in the sub-scanning direction is appropriately provided at a position facing the document placing plate 70a. When the image reading device Aa is configured as a so-called handy scanner type contact image sensor, the platen roller 98 is not provided and the case 4
The user will hold a by hand as it is. The basic configuration of the image reading device Aa is the same as that of the image reading device A of the previous embodiment.
Light emitted from the light source 2 mounted on the circuit board 6 can be appropriately guided to a predetermined image reading area S by the light guide member 1. As described above, the image reading device according to the present invention is not limited to the flatbed type image sensor, and may be configured as a contact type image sensor.

FIGS. 10 to 12 are explanatory views showing other examples of the main structure of the image reading apparatus according to the present invention.

In the configuration shown in FIG. 10, both ends in the longitudinal direction of the transparent member 10 constituting the light guide member 1B are connected to the light incident portions 15,
The two light sources 2 facing the light incident portions 15 are mounted on both ends in the longitudinal direction of the circuit board 6 on which a light receiving element (not shown) is mounted. According to such a configuration, the light emitted from each of the two light sources 2, 2 is made to enter the light guide member 1B from each of the two light incident portions 15, 15, and is formed by the inclined surfaces 16, 16. By reflecting the light, the light guide member 1B can be advanced to the center in the longitudinal direction from both ends. Then, light can be emitted from various parts of the first side surface 10A. As described above, in the present invention, a light incident portion may be provided at each of both ends in the longitudinal direction of the light guide member. According to such a configuration, as much light as possible can be made to enter the light guide member as much as the number of light sources can be increased, and the amount of light emitted from the first side surface 10A can be increased.

In the structure shown in FIG. 11, the light guide member 10 constituting the light guide member 1C has a light incident portion 15 at a longitudinally intermediate portion thereof. Light source 2 is mounted. In the first side surface 10A of the light guide member 1, a concave portion 18 having a substantially V-shaped cross section having two inclined surfaces 18a, 18a is formed at a position facing the light incident portion 15. . The inclined surface 1
8a, 18a, the outer surface of each
A light reflecting layer 3C is provided to prevent the light from passing through a and 18b from leaking to the outside. According to such a configuration, when the light emitted from the light source 2 enters the light guide member 1C from the light incident portion 15, the light is transmitted to both ends in the longitudinal direction of the light guide member 1C by the inclined surfaces 18a and 18b. Proceed in the direction of the part. Then, the inclined surfaces 18a, 1
Light will be emitted from each part of the first side surface 10A except for the portion 8b. As described above, in the present invention, the light incident portion may be provided at the middle portion in the longitudinal direction of the light guide member. In such a case, for example, as shown in FIG.
5 may be provided at a plurality of locations in the longitudinal middle part of the light guide member 1D. With such a configuration, the number of light sources 2 can be easily increased, and the first side surface 1 of the light guide member 1D can be increased.
The amount of light emitted from OA can be easily increased.

FIGS. 13 to 17 are sectional views showing other examples of the light guide member applied to the image reading apparatus according to the present invention.

The light guide member shown in FIG.
The entire surface of 0C is an inclined surface. Thus, in the present invention, either the configuration in which the entire surface of the third side surface is inclined, or the configuration in which only a part of the third side surface is inclined as described in the above embodiment, may be used.

The light guide member shown in FIG.
0D is a plane that is not inclined with respect to the second side surface 10B. Even with such a configuration, light can be efficiently emitted from the first side surface 10A in a predetermined oblique direction by the light reflecting action of the third side surface 10C which is an inclined surface,
The object of the present invention can be achieved.

The light guide member shown in FIG.
The chamfered inclined surface 93 is provided near the lower portion of the first and fourth side surfaces 10D.
a, 93b. According to such a configuration, when the light that has entered the light guide member from the light source 2 at a large spread angle reaches the inclined surfaces 93a and 93b, the incident angle with respect to the inclined surfaces 93a and 93b is increased. Can be. Therefore, it is possible to reduce a possibility that light is transmitted to the outside of the light guide member.

The light guide member shown in FIG.
Is a curved inclined surface. The fourth side surface 10D is also a curved inclined surface. As described above, in the present invention, when a predetermined surface is an inclined surface, this surface may be formed not only in a plane but also in a curved shape. In the present invention, instead of such a smooth curved surface,
For example, a plane in which a plurality of minute planes having different inclination angles are connected in series may be used.

The light guide member shown in FIG.
And the second side surface 10B are not parallel to each other,
0A is an inclined surface inclined with respect to the second side surface 10B. If the first side surface 10A is formed as such an inclined surface, the first side surface 10A can directly face a desired image reading region located obliquely above the first side surface 10A, and the light irradiation efficiency to the image reading region can be further improved. Can be enhanced. Of course, as described above, the first side surface 10
A and the second side surface 10B are not parallel, the first side surface 1
It is possible to appropriately emit light from various places of 0A.

As described above, the specific shape of the light guide member used in the image reading device of the present invention can be variously changed in design, and light guide members having various shapes other than those described above can be used. is there. Further, as understood from the above-described embodiment, the light guide member used in the present invention has at least a first side surface, a second side surface, a third side surface, and a fourth side surface. In addition, it may be formed in a polygonal column shape having another side surface such as the fifth side surface or the sixth side surface. Further, the cross-sectional shape of the light guide member does not necessarily have to be the same at various places.

In addition, the specific configuration of each part of the image reading apparatus according to the present invention can be variously changed in design.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a light guide member according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a partially omitted sectional view showing an example of the image reading apparatus according to the present invention.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

7 is an exploded perspective view of the image reading device shown in FIG.

FIG. 8 is a cross-sectional view showing an example of a means for fixing and holding the light guide member on the light reflection member.

FIG. 9 is a sectional view showing another example of the image reading apparatus according to the present invention.

FIG. 10 is an explanatory diagram showing another example of a main structure of the image reading apparatus according to the present invention.

FIG. 11 is an explanatory view showing another example of a main structure of the image reading apparatus according to the present invention.

FIG. 12 is an explanatory diagram showing another example of a main part structure of the image reading apparatus according to the present invention.

FIG. 13 is a sectional view showing another example of the light guide member used in the image reading device according to the present invention.

FIG. 14 is a sectional view showing another example of the light guide member used in the image reading device according to the present invention.

FIG. 15 is a cross-sectional view showing another example of the light guide member used in the image reading device according to the present invention.

FIG. 16 is a sectional view showing another example of the light guide member used in the image reading device according to the present invention.

FIG. 17 is a sectional view showing another example of the light guide member used in the image reading device according to the present invention.

FIG. 18 is a perspective view illustrating an example of a conventional image reading apparatus.

FIG. 19 is an explanatory diagram showing the operation of the linear light source device applied to the conventional image reading device shown in FIG.

[Explanation of symbols]

 1, 1A to 1D Light guide member 2 Light source 3A First light reflection member 3B Second light reflection member 4, 4a Case 6 Circuit board 10 Transparent member 10A First side surface 10B Second side surface 10C Third side surface 10D Fourth side surface 10E, 10F End surface 15 Light incident portion 16 Inclined surface 18 Concave portion 51 Condensing lens 52 Light receiving element 70, 70a Document mounting plate A, Aa Image reading device K Document S Image reading area

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Norihiro Imamura Inventor No. 21 Saizou Mizozakicho, Ukyo-ku, Kyoto-shi ROHM Co., Ltd.

Claims (9)

[Claims] A plurality of light receiving elements arranged in a row in an image reading line direction so as to be able to receive light traveling from a predetermined image reading area; a circuit board on which the plurality of light receiving elements are mounted; A light guide member made of a transparent member having a constant length disposed on one side of an optical path from the image reading area to the plurality of light receiving elements, and a light source,
The light guide member includes a plurality of side surfaces extending in the image reading line direction, a first side surface and a second side surface separated in the thickness direction of the light guide member, and a third side surface separated in the width direction of the light guide member. An image reading device having a side surface and a fourth side surface, wherein the light source is mounted on a common surface of the circuit board on which the plurality of light receiving elements are mounted, and The light guide member is disposed such that a part of the second side surface faces the light source, and light incident into the light guide member from a part of the second side surface is reflected by the plurality of side surfaces. The light guide member is formed so as to emit to the outside from the entire area or substantially the entire area of the first side face while traveling in the longitudinal direction, and the entire or a part of the third side face of the light guide member is From the direction of the second side surface, The light traveling in the thickness direction of the member, characterized in that an inclined surface that faces the reflective capable the second side in the direction toward the image reading region via the first aspect, the image reading apparatus. 2. The inclined surface of the third side surface is a flat surface, a curved surface,
The image reading device according to claim 1, wherein the image reading device is a surface in which a plurality of planes having different angles stepwise are connected in series. 3. The entire surface or a part of the fourth side surface,
3. An inclined surface inclined in the same direction as the inclined surface of the third side surface, wherein the first side surface is arranged to be closer to the image reading area than the second side surface. An image reading device according to claim 1. 4. An outer surface of the light guide member, except for a part of a second side surface facing the light source and a whole or part of a region excluding the first side surface, is covered with a light reflection member.
The image reading device according to claim 1. 5. The image reading device according to claim 4, wherein the light reflecting member is a member that scatters and reflects the received light. 6. The light guide member according to claim 1, wherein a longitudinal end of a second side surface of the light guide member is a light incident portion facing the light source, and a position of the first side surface facing the light incident portion is the light incident portion. The image reading device according to any one of claims 1 to 5, further comprising an inclined surface that reflects light that has entered the light guide member from the light incident portion toward a central portion in the longitudinal direction of the light guide member. apparatus. 7. The light guide member according to claim 1, wherein a middle portion in the longitudinal direction of the second side surface is a light incident portion facing the light source, and a position of the first side surface opposed to the light incident portion is the light incident portion. A concave portion having a substantially V-shaped cross section and having two inclined surfaces for reflecting light incident into the light guide member from the light incident portion toward both ends in the longitudinal direction of the light guide member is provided. Item 1
6. The image reading device according to any one of claims 5 to 5. 8. The light source according to claim 1, wherein the light source is an LED light source that emits white light or monochromatic light of any other color, or an LED light source that combines LEDs that emit light of R, G, and B colors. The image reading device according to any one of the above. 9. The image reading device according to claim 1, wherein said light source is an LED chip directly bonded to said circuit board.