JPH10276296A - Contact type color image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable miniaturization without practical degradation in read picture quality by specifying the position relation among 'Selfoc<(> R<)> ' lens, image reading plane and light receiving element corresponding to the conjugate length of lens. SOLUTION: Respective LED 3A-3C light emission in R, G and B as three primary colors of light are used one by one but corresponding to the conjugate length (TC) of 'Selfoc<(> R<)> ' lens 51 concerning the intermediate wavelength zone between R and G, namely, light in orange, for example, the mutual relational positions of image reading plane 53, 'Selfoc<(> R<)> ' lens 51 and image sensor chip 52 are set. Namely, the conjugate length TC is TC for the light in orange, and the image reading plane 52 at a 1st focal position F1 specified by this TC and the main side of image sensor chip 52 at a 2nd focal position F2 are respectively positioned. Thus, the contact type color image sensor is sealed for preventing the read picture quality from being practically lowered by using the 'Slfoc<(> R<)> ' lens having a comparatively long rod lens length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type color image sensor capable of reading a color image.

[0002]

2. Description of the Related Art Regardless of whether a color image can be read or a monochrome image can be read, a contact type image sensor generally has the following configuration. That is, as shown in FIG. 24 of the present application, the light source device B is placed on the image reading surface 90 made of a transparent glass 91 or the like on which the read original G is closely conveyed to the front side.
And the reflected light from the read original is focused on the light receiving element on the image sensor chip 52e via the SELFOC lens 51e. The image sensor chip 52e has, for example, 8 dots / m
When an image is read at a reading density of m, the light receiving elements are semiconductor chips integrally formed on the main surface at intervals of 0.125 mm. In one image sensor chip 52e, for example, 64 light receiving elements are formed at equal intervals. For example, in order to read an original of A4 width, a light receiving element of 1728 dots required for reading is required. A series of 27 image sensor chips are arranged in a row.

The selfoc lens 51e is formed by inserting a number of special rod lenses extending in the optical axis direction into an opaque holder resin, and has a specific focal length called a conjugate length (TC). The selfoc lens 51e has a function of forming an image existing at one focal position defined by the conjugate length at the same focal length on the other focal position at the same erect magnification. When a contact image sensor is configured, the relationship between the selfoc lens 51e, the image sensor chip 52e, and the image reading surface 90 is as follows.
With the Selfoc lens 51e interposed therebetween, the image reading surface 90 is set at one focal position, and the main surface of the image sensor chip 52e is set at the other focal position. However, since the image reading surface is formed of a member having a refractive index n of about 1.4 to 1.5, such as a transparent glass as described above, the focal length at one of the focal positions is equal to that of the transparent glass. It is extended by an amount corresponding to the distance obtained by multiplying the thickness by (n-1). In this specification, the focal length or focal position or conjugate length is:
As described above, the term includes a distance substantially extended by transmitting light through glass or the like.

Since the light receiving elements on each image sensor chip are arranged in a straight line, the image reading surface has
A linear read line L is set. That is, the image of the original conveyed on the image reading surface 90 is read line by line in the reading line L.

In the case of reading a color image, the light source 3e is provided with three primary colors of light, R (red) and G.
Light sources of three colors (green) and B (blue) are arranged. The three primary colors of light are complementary to the three primary colors C (cyan), M (magenta), and Y (yellow). That is, R light is absorbed by C color, G light is absorbed by M color, and B light is absorbed by Y color. In the operation as a color image sensor, the R, G, and B light sources are sequentially turned on, and the C color component becomes G due to the reduction rate of the reflected light from the original on the reading line L when the R light is irradiated. The M color component is determined by the reduction rate of the reflected light from the document when the light is irradiated, and the Y component is determined by the reduction rate of the reflected light from the document when the B light is irradiated.
Read sequentially.

[0006]

By the way, the nominal conjugate length (TC ₀ ) expressed in the specification of the selfoc lens is described above.
Is for light in a specific wavelength range. However, when configuring a color image sensor, R,
G and B light sources of three colors are used.
The actual conjugate length for G and B light is different from the above-mentioned nominal conjugate length. Generally, due to the refraction characteristics of light,
The actual conjugate length (focal length) of the selfoc lens is longer in the case of light having a short wavelength and in the case of light having a long wavelength in the latter case than in the former case. Therefore, when configuring a color image sensor, for example, the nominal conjugate length (TC
_If the positional relationship between the selfoc lens, the image reading surface, and the main surface of the image sensor chip is defined in accordance with ₀ ), light sources having different wavelengths are turned on for specific light for determining the nominal conjugate length. In this case, the aberration is enlarged, and the read image is blurred. This leads to a reduction in the quality of a read color image.

In general, a selfoc lens having a longer rod lens length as shown in FIG. 2B has a shorter rod lens length and a shorter conjugate length as shown in FIG. 2A. The difference in conjugate length when the light wavelength ranges are different is small. Therefore, at present, as a means for solving the above-described problem in forming a color image sensor, a self-lens for reading a monochrome image having a short rod lens length as shown in FIG. A selfoc lens having a long rod lens length as shown in FIG. 2B is used as a selfoc lens for reading a color image.

However, the use of a selfoc lens having a long rod lens length as described above is not suitable for use in FIG.
Obviously, in view of the structure of the contact type image sensor described in (1), it is impossible to meet the demand for downsizing of this type of contact type color image sensor. In addition, the cost of the SELFOC lens itself increases, and the amount of light reaching the light receiving element from the document reading surface decreases, which causes a problem that the performance of the image sensor is deteriorated.

The present invention was conceived under the circumstances described above, and is capable of responding to a demand for downsizing without substantially deteriorating the quality of a read image. It is an object of the present invention to provide a contact type color image sensor configured as described above.

[0010]

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

That is, in the contact type color image sensor according to the present invention, an image reading surface on which a read original is closely conveyed, a plurality of light receiving elements arranged in a line, and illumination of the read original on the image reading surface. R for
A contact type color image sensor comprising: G and B light sources; and a selfoc lens disposed between the image reading surface and the light receiving element for focusing an image of a read document on the image reading surface onto the light receiving element. And a positional relationship between the selfoc lens, the image reading surface, and the light receiving element is defined corresponding to a conjugate length of the selfoc lens for an intermediate wavelength range between R and G. It is characterized by having.

In other words, regarding the relationship between the selfoc lens, the image reading surface, and the light receiving element, the image reading surface is located at the first focal position of the selfoc lens for an intermediate wavelength range between R and G. The light receiving elements are respectively arranged at the second focal position.

In a preferred embodiment, the contact-type color image sensor is formed by a casing, a surface of a transparent cover glass attached to one surface of the casing, and an image reading surface on which a document to be read is closely transported; A plurality of light receiving elements arranged in a line on a main surface of a plurality of image sensor chips mounted on a substrate mounted on the other surface side, and reading on the image reading surface provided in the casing; R, G, and B light sources for illuminating a document, and a selfoc lens disposed between the image reading surface and the light receiving element for focusing an image of the read document on the image reading surface onto the light receiving element. And the positional relationship between the Selfoc lens, the image reading surface, and the light receiving element is In correspondence with the conjugation length of the SELFOC lens for the intermediate wavelength region of R and G are set, and the distance between the image reading surface and the light-receiving element is a 12mm or less.

FIG. 1 shows a nominal conjugate length TC ₀ = 9.1 mm.
10 is a graph showing a relationship between TC and resolution for each of R, G, and B color lights for a selfoc lens (at λ = 570 nm). The R color light has a wavelength λ = 650 nm, G
The color light has a wavelength λ = 525 nm, and the B color light has a wavelength λ = 47.
0 nm. As can be seen from this graph, for R color light, TC _RED = around 9.6 mm, for G color light, around TC _GREEN = 8.8 mm, and for B color light, around TC _BLUE = 8.5 mm, respectively. The resolution becomes the maximum (65%). Then, for each color, when TC deviates from the value at which the resolving power becomes maximum as described above, the resolving power decreases. Here, the resolving power is a concept that the image blur increases as its value decreases.

In the present invention, the selfoc lens, the image reading surface, and the light receiving element are arranged so as to correspond to the conjugate length at which the resolving power of the selfoc lens in the intermediate wavelength range between R and G is maximized. The positional relationship between them is defined. For example, in the graph of FIG. 1, assuming a TC-resolution characteristic for orange light that is an intermediate wavelength color between R and G, the resolution becomes maximum near TC = 9.2 mm as indicated by a broken line in the figure. . In the present invention, when a contact type color image sensor is configured using the above-described Selfoc lens, the distance between the image reading surface and the light receiving element is set in accordance with the above TC = 9.2 mm. You do it.

As can be seen from FIG. 1, when TC = 9.2 mm, the resolving power for R-color light and the resolving power for G-color light slightly decrease from the maximum value (65%), but are maintained at high levels. On the other hand, the resolving power for the B color light is reduced to about 37%. This, however, has little adverse effect on the reading quality of color images for the reasons described below.

That is, as described above, the R color light is used as a light source for reading the C color component on the read document, the G color light is used as the M color component, and the B color light is used as a light source for reading the Y color component. The image of the C color component, the image of the M color component, and the image of the Y color component thus read are superimposed to reproduce a color image. However, since the Y color is weak, the Y color image is slightly Even if the resolution is reduced, that is, even if the image is slightly out of focus, if the resolution of the C color image and the M color image is maintained at a predetermined level or more, the resolution of the final color image is maintained. Is not noticeably reduced.

In the present invention, when the selfoc lens is arranged as described above, the resolving power for B color light is reduced. However, since this is for reading the Y color component in the read original, the color image sensor reads the Y color component. The quality of the resulting final color image is not unnecessarily degraded.

Therefore, according to the present invention, even when a contact-type color image sensor is formed using a selfoc lens having a relatively short rod lens length, it is possible to substantially avoid a reduction in image reading quality. be able to. The fact that such a selfoc lens having a short rod lens length can be used means that R, G, B
This also means that it is possible to easily and miniaturize the contact type color image sensor without increasing the output of the light source beyond a predetermined value. In addition, it is possible to solve the problem that the cost of the selfoc lens itself is increased as in the case of a collar selfoc lens having a long rod lens length.

In a preferred embodiment, the above R,
The G and B light sources are mounted on the substrate, and a light guide member for guiding light emitted from the light source to the image reading surface is provided in the casing.

With this configuration, the R, G, and B light sources can be mounted on the same substrate as the substrate on which the image sensor chip as the light receiving element is mounted, so that the electrical configuration of the image sensor is simplified. Become.

In a preferred embodiment, each of the R, G, and B light sources has one point light source disposed at the center in the longitudinal direction of the substrate, and the light guide member has the R, G, and B light sources. The light emitted from the G and B light sources is configured to be dispersed and emitted to a region extending in the longitudinal direction of the casing on the image reading surface.

With this configuration, since the light from the point light source is dispersed along the reading line, the amount of light at each part of the reading line tends to decrease. As described above, in the present invention, Since a selfoc lens having a short rod lens length and high light transmission efficiency can be used as the selfoc lens, the image reading performance of the image sensor does not decrease. Further, since one light source for each of R, G, and B is used, the cost of the light source is also reduced. Further, since the light from the point light source arranged at the center in the longitudinal direction of the substrate is dispersed in the longitudinal direction of the casing, it is possible to make the entire length of the casing the shortest dimension corresponding to the reading length. This also contributes to downsizing of this type of contact type color image sensor.

Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0025]

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

FIG. 3 is a sectional view of a main part showing an embodiment of the contact type color image sensor A according to the present invention. FIG. 4 is a sectional view taken along line X1-X1 in FIG. FIG.
FIG. 4 is a sectional view taken along line X2-X2 in FIG. FIG.
FIG. 4 is a cross-sectional view illustrating a state in which the image reading device A illustrated in FIG. 3 is assembled. FIG. 7 shows the image reading device A shown in FIG.
FIG. 3 is an exploded perspective view of FIG.

As shown in FIG. 7, the image reading apparatus A includes a casing 4, a cover glass 4A, a circuit board 6 on which a large number of light receiving elements (image sensor chips) 52 for reading images are mounted, The three LEDs 3 (3A to 3C) mounted on the board 6, a plurality of attachments 69 for attaching the circuit board 6 to the bottom of the casing 4, a selfoc lens array 51, and light emitted from the LEDs 3 A first light guide member 1 and a second light guide member 2 for guiding to a predetermined position are provided. Further, the contact type color image sensor A includes a first light reflecting plate 8A, a second reflecting plate 8B, and a first light reflecting plate 8A for preventing light from leaking from the first light guiding member 1 or the second light guiding member 2. A fixing member 7A and a second fixing member 7B are also provided. The first fixing member 7A is provided with a plurality of light shielding plate portions 72.

The casing 4 is made of, for example, a synthetic resin, and is formed in an elongated box shape having an open upper surface.
The cover glass 4A is mounted so as to close the upper surface opening of the casing 4, and the surface thereof forms an image reading surface on which a read document is conveyed in close contact.
As shown in FIGS. 4 and 5, the original G is conveyed in close contact with the platen roller 9 on the image reading surface 53 of the cover glass 4A.

FIG. 8 is a front view of the first light guide member 1. FIG. 9 is a plan view of the first light guide member 1. FIG.
0 is a sectional view taken along line X3-X3 in FIG. FIG.
FIG. 9 is a sectional view taken along line X4-X4 in FIG. FIG.
FIG. 9 is a sectional view taken along line X5-X5 in FIG.

The first light guide member 1 is, for example, a PMMA
The first transparent member 10 obtained by molding an acrylic transparent resin such as that described above occupies the main part. The first light guide member 1 is an elongated rod having a certain dimension in the longitudinal direction, and has a first side surface 10A and a 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. The first side surface 10A and the second side surface 10B oppose each other in the vertical thickness direction, and preferably, the width of the first side surface 10A is smaller than the width of the second side surface 10B. The third above
The side surface 10C and the fourth side surface 10D face each other in the width direction of the first light guide member 1.

The first side surface 10A is a portion serving as a light emitting surface of the first light guide member 1 as described later, and is preferably a mirror-like plane. In addition, the third side 1
OC and the fourth side surface 10D are also mirror-like planes. The mirror-like plane does not necessarily need to be a surface whose surface is actively polished. For example, when the first light guide member 1 is resin-molded using a mold, A relatively smooth surface obtained by resin molding is also included in the concept of a mirror-like plane. If the surface of the transparent member is a mirror-like flat surface, it is possible to reflect all light incident on the surface at an angle larger than the total reflection critical angle specified by the material of the transparent member, Light incident at an angle smaller than the reflection critical angle can be transmitted.

At the center of the first side surface 10A in the longitudinal direction, there is provided a substantially V-shaped concave portion 11 as viewed from the front. The recess 11 forms two inclined surfaces 11a, 11a, and these two inclined surfaces 11a, 11a are also mirror-like. In the present embodiment, the two inclined surfaces 11a, 11a are convex curved surfaces, and the boundaries between the upper portions of the inclined surfaces 11a, 11a and other regions of the first side surface 10A are sharp. It is formed so as not to have an edge shape. The inclined surfaces 11a, 11a are shown in FIG.
As shown in FIG. 3, the light source is a part that reflects light emitted from the LED 3 and incident on the inside of the first light guide member 1 so as to travel toward both ends in the longitudinal direction of the first light guide member 1. A curved surface is formed by connecting a series of surfaces that totally reflect the light emitted from the LED 3 as a point light source.

A concave portion 16 is formed at the center in the longitudinal direction of the second side surface 10 B, and the portion where the concave portion 16 is formed is a light incident portion 15. The recess 16 is LE
It has a size that allows D3 to be placed inside it,
The cross section has a substantially trapezoidal shape that becomes narrower as it goes to the back so as to facilitate the insertion positioning of the LED 3. The recess 16 faces the center of the recess 11.

In a region other than the light incident portion 15 of the second side surface 10B, a plurality of concave portions 14 are provided at appropriate intervals. The region between the plurality of concave portions 14 is a mirror-shaped flat portion 13. The plurality of concave portions 14
Is a part that plays a role in causing the traveling angle of light traveling inside the first light guide member 1 to rapidly change and emit the light from the first side surface 10A, and has, for example, an arc-shaped cross section and a curved inclined surface 14a. have. Also, the second side surface 10B
Is formed as an inclined surface that gradually reduces the thickness of the first light guide member 1 from the center in the longitudinal direction to both ends in the longitudinal direction. If the second side surface 10B is formed as such an inclined surface, light traveling from the central portion in the longitudinal direction to both ends in the longitudinal direction of the first light guide member 1 can be efficiently incident on the inclined surface 14a. Is preferable.

The third side surface 10C is provided with a plurality of holes 18 at appropriate intervals in the longitudinal direction.
The plurality of holes 18 are formed in a long hole shape elongated in the longitudinal direction of the first light guide member 1. As described later, the plurality of holes 18 are used to attach the second fixing member 7B to the first light guide member 1. On the other hand, a concave portion 19 is provided at each of both longitudinal end portions of the first side surface 10A. The recess 19 is used to connect the first light guide member 1 and the second light guide member 2 to each other, as described later.

The first light guide member 1 plays a role of dispersing the light emitted from the LED 3 into a band extending in the longitudinal direction of the read line L of the image reading surface 53 and emitting the light from the first side surface 10A. Specifically, as shown in FIG.
In a state where the LED 3 is arranged in the recess 16,
When the LED 3 emits light, the light enters the first light guide member 1 from the light incident portion 15 at an appropriate spread angle. Most of the light reaches the two inclined surfaces 11a, 11a facing the light incident portion 15. However, since these inclined surfaces 11a, 11a are inclined with respect to the longitudinal direction of the first light guide member 1, the inclined surfaces 11a
The incident angle of light that directly reaches the first and the second transparent members 10a and 11a can be made larger than a predetermined total reflection critical angle specified by the material of the first transparent member 10. Therefore, the first light guide member 1
Most of the light that has entered inside can be prevented from transmitting through the inclined surfaces 11a and 11a and exiting as it is.

In FIG. 13, most of the light incident on the first light guide member 1 from the light incident portion 15 is totally reflected by the inclined surfaces 11a, 11a. You will go in the direction. Then, the first side surface 10
A, the first light guide member 1 reaches both ends in the longitudinal direction of the first light guide member 1 while repeating total reflection at each of the second side surface 10B, the third side surface 10C, and the fourth side surface 10D. Second side surface 10
When light is incident on B, the light is totally reflected in each plane portion 13. On the other hand, the inclined surface 1 of the concave portion 14
Most of the light incident on 4a is reflected in a form close to scattered reflection, and the course of the light is rapidly changed. Then, the possibility of incidence on the first side surface 10A at an incident angle smaller than the critical angle for total reflection is increased. Therefore, most of the light reflected by the inclined surface 14a and traveling in the direction of the first side surface 10A passes through the first side surface 10A and is emitted to the outside of the first light guide member 1. Therefore, even though the light incident portion 15 is provided at the central portion in the longitudinal direction of the first light guide member 1, it is possible to emit light almost uniformly from the entire longitudinal length region of the first side surface 10A.

FIGS. 15A and 15B show the second light guide member 2, wherein FIG. 15A is a plan view thereof and FIG. 15B is a front view thereof. FIG. 16 is a sectional view taken along line X6-X6 in FIG. FIG. 17 is a cross-sectional view taken along line X7-X7 in FIG.

The main part of the second light guide member 2 is a second transparent member 20 obtained by molding an acrylic transparent resin such as PMMA of the same material as the first light guide member 1. I have. The size of the second light guide member 2 in the longitudinal direction is substantially the same as the size of the first light guide member 1, and as is well shown in FIG. 16 and FIG. 2, a first side surface 20A, a second side surface 20B, a third side surface 20C, and a fourth side surface 20D extending in the longitudinal direction.
It has. Each of these four side surfaces 20A to 20D has a mirror surface. The first side surface 20A and the second side surface 20B face each other in the thickness direction of the second light guide member 2, and a part of the area of the second side surface 20B is, as shown in FIG. 4 and FIG. The first light guide member 1 serves as a light incident portion 25 for allowing light to enter the second light guide member 2 from the first side surface 10A. On the other hand, a partial area of the first side surface 20A is
And a light emitting surface that emits light toward. As shown in FIG. 16, the first side surface 20A and the second side surface 20B are provided with appropriate steps H1 and H2. The step H1 is provided for the purpose of making a part of the first light reflection plate 8A adhere to the first side surface 20A of the second light guide member 2 as shown in FIG. Further, the step H2 serves to avoid interference between the second light guide member 2 and the SELFOC lens array 51. Therefore,
The steps H1 and H2 do not necessarily need to be formed in the second light guide member 2.

The third side surface 20C and the fourth side surface 20D are opposed to each other in the width direction of the second light guide member 2, and are inclined surfaces inclined at a predetermined angle. As shown in FIG.
The third side surface 20C is a light reflection surface that reflects the light that has entered the second light guide member 2 from the light incident portion 25 in the direction of the fourth side surface 20D. On the other hand, the fourth side surface 20D is
The light reflected from the third side surface 20C is converted to the second light.
This is a light reflection surface that reflects light in the direction of the image reading surface 53 above the light guide member 2 and emits light from a partial area of the first side surface 20A. The third side surface 20C is provided with a plurality of holes 27 at appropriate intervals along the longitudinal direction.
Each of the plurality of holes 27 has a long hole shape elongated in the longitudinal direction of the second light guide member 2, and has a first hole therein as described later.
The projection 71A of the fixing member 7A is fitted.

Each of the two longitudinal end portions of the second side surface 20B is provided with a downwardly projecting portion 23. The convex portion 23 can be fitted (press-fitted) into the concave portion 19 of the first light guide member 1, and by this fitting operation, the light incident portion 25 of the second light guide member 2 and the first light guide member 1 can be fitted. The second light guide member 2 and the first light guide member 2 are arranged so that the first side surface 10A faces each other.
It is possible to connect the light guide member 1 to each other.

At the substantially central portion in the longitudinal direction of the second side surface 20B, two convex portions 24, 24 are provided so as to protrude downward at predetermined intervals. Therefore, when the second light guide member 2 and the first light guide member 1 are connected to each other, as shown in FIG. The first side surface 10A and the light incident portion 25 are prevented from coming into face-to-face contact with each other over a wide area because the first side surface 10A comes into contact with the first side surface 10A of the light guide member 1. That is, an air layer serving as the gap Sa is formed between the first side surface 10A and the light incident portion 25. When the first side surface 10A and the light incident portion 25 are in close contact with each other, light traveling in the first light guide member 1 emits light from the first side surface 10A.
At the time of incidence on A, there is a possibility that the light may enter the inside of the second light guide member 2 irrespective of the angle of incidence, but if the air layer is formed as described above, The first
Light incident on the side surface 10A at an angle larger than the predetermined critical angle for total reflection can be reliably totally reflected by the first side surface 10A.

Projections 29, 29 are provided on the end surfaces of both ends of the second light guide member 2 in the longitudinal direction. On the other hand, as is clearly shown in FIGS. 3 and 7, recesses 40, 40 into which the protrusions 29, 29 can be fitted (press-fitted) are formed on the upper surfaces of both ends in the longitudinal direction of the casing 4. Is provided. That is, the second light guide member 2 is positioned and fixed with respect to the casing 4 by fitting the respective protrusions 29 into the respective recesses 40 of the casing 4. Also, as shown in FIGS.
Another protruding portion 28 projects downward at the center in the longitudinal direction of the second side surface 20B of the second light guide member 2. When the second light guide member 2 is accommodated and arranged in the casing 4, as shown in FIGS. 4 and 5, the projection 28 fits into a recess 41 provided in the casing 4. By doing so, the second light guide member 2 is positioned in the longitudinal direction.

The first light guide member 1 and the second light guide member 2
Is housed and arranged inside the casing 4 below the cover glass 4A. The first light guide member 1 includes a selfoc lens array 51 and an image sensor chip 52.
The light incident portion 15 is provided on one side of the arrangement space of the LED 3 (3A to 3A) mounted on the circuit board 6.
It faces downward so as to face C). On the other hand, the second light guide member 2 is provided on the first side surface 1 of the first light guide member 1.
The light emitted from substantially the entire length range of 0A is disposed below the image reading surface 53 so as to be sequentially reflected by the third side surface 20C and the fourth side surface 20D to be guided to the image reading surface 53.

FIG. 18 shows a developed state of the first light reflecting plate 8A, and FIG. 18A is a plan view. FIG.
FIG. 3A is a cross-sectional view taken along line X8-X8 in FIG. 3A, and FIG. 3C is a cross-sectional view taken along line X9-X9 in FIG. FIG. 19 is a perspective view showing a state where the first light reflecting plate 8A is assembled in a three-dimensional manner.

The first light reflecting plate 8A is provided with the first light guide member 1
And a member for preventing light from leaking through the inside of the second light guide member 2. The surface of the first light reflection plate 8A is white so that the light reflection efficiency is increased. The first light reflection plate 8A can be formed by a thin synthetic resin sheet 80 cut into a predetermined shape as shown in FIG. This sheet body 80
Are substantially the same as the longitudinal dimensions of the first light guide member 1 and the second light guide member 2.
A plurality of bending lines N for three-dimensionally assembling 0 are provided.

As shown in FIG. 19, the first light reflecting plate 8A is formed by bending the sheet member 80 along each of the bending lines N, so that the first light guiding member 1 and the second light guiding member 2 are formed. Is formed in a shape capable of covering a predetermined outer surface of the. Further, side pieces 80a, 80a are provided at both ends in the longitudinal direction of the first light reflection plate 8A, and by folding the side pieces 80a, 80a, respectively, as shown in FIG. The end face 10F (10
E). In FIGS. 18 and 19, an elongated through hole 82 is provided at a predetermined position in the longitudinal center of the first light reflecting plate 8A. The through holes 82 are holes through which the light shielding plate 72 of the first fixing member 7A is inserted. When the light-shielding plate 72 is thin, the through-hole 82 may be formed as a narrow through-hole such as a score line. If provided, each of the plurality of light shielding plate portions 72 may be formed as a perforated through hole that allows individual insertion. A plurality of other through-holes 83a and 83b are provided in a portion corresponding to the regions 80c and 80f of the first light reflection plate 8A at appropriate intervals in the longitudinal direction. The plurality of through holes 83a and 83b are formed by the first fixing member 7A and the second
A hole through which the protrusions 71A and 71B of the fixing member 7B are inserted.

In FIG. 7, the second light reflecting plate 8B is
It is formed of a white sheet member similar to the first light reflection plate 8A, and is a member for preventing light from transmitting through the fourth side surface 20D of the second light guide member 2.
Therefore, the shape and size of the second light guide member 2
Is similar to the fourth side surface 20D. This second light reflection plate 8B
Is sandwiched between the fourth side surface 20D of the second light guide member 2 and the inner wall surface of the casing 4 facing the fourth side surface 20D, as best seen in FIGS. 2
It is in close contact with 0D. FIG. 20A is a plan view of the first fixing member 7A, and FIG. 20B is a front view thereof. FIG. 21 is a cross-sectional view taken along line X10-X10 in FIG. FIG. 22 is a view showing the state of X11-X in FIG.
It is sectional drawing in alignment with line 11.

The first fixing member 7A is made of the same material as the first light guiding member 1 and the second light guiding member 2, and is made of, for example, P
It is made of acrylic synthetic resin such as MMA. However, the overall color is white with high light reflection efficiency. The first fixing member 7A is provided on one side surface portion 73A of the fixing member main body 70A formed in a substantially plate shape having substantially the same length as the entire length in the longitudinal direction of the first light guide member 1 and the second light guide member 2.
A plurality of flat projection-like light shielding plate portions 72 are provided in a protruding manner.

The plurality of light shielding plate portions 72 are provided in a stripe shape in a plan view so as to be spaced from each other so as to form a gap between them. The light shielding plate portion 72 has a white surface like the other portions of the first fixing member 7A, and has a surface that scatters and reflects received light.

As shown in FIG. 5, the first fixing member 7A inserts each of the projections 71A into each of the through holes 83a of the first light reflection plate 8A, and inserts the distal end thereof. The second light guide member 2 is attached to the second light guide member 2 by being further fitted into each of the holes 27. By attaching the first fixing member 7A, the first
A predetermined region of the light reflecting plate 8A is pressed by one side surface portion 73A of the fixing member main body 70A and is in close contact with the fourth side surface 10D of the first light guide member 1 and the third side surface 20C of the second light guide member 2. . In the state where the first fixing member 7A is mounted, the plurality of light shielding plate portions 72 are connected to the first light reflection plate 8.
A of the first side surface 1 of the first light guide member 1
0A and the light incident portion 25 of the second light guide member 2. As shown in FIG. 3, the plurality of light shielding plate portions 72 are opposed to the concave portions 11 of the first light guide member 1.

As shown in FIG. 5, the fixing member main body 70A includes a first light guide member 1 and a second light guide member 2 covered with a first light reflection plate 8A.
The first light reflection plate 8A is formed into a shape and a size that can be fitted into the gap S1 on one side of the first light reflection plate 8A that can be generated when the first light reflection plate 8A is accommodated in the inside. Therefore, in a state where the first fixing member 7A is disposed at a predetermined position in the casing 4, the first light guide member 1 and the second light guide member 2 are disposed on one side of the first light reflection plate 8A. The gap (gap S1) that causes rattling can be filled by the first fixing member 7A.

FIG. 23 shows the second fixing member 7B.
FIG. 1A is a front view. FIG. 3B is a cross-sectional view taken along line X12-X12 in FIG. FIG. 3C is a cross-sectional view taken along line X13-X13 in FIG.

The second fixing member 7B is, like the first fixing member 7A, provided with the first light guiding member 1 and the second light guiding member 2.
And the whole color is white, which has high light reflection efficiency. This second fixing member 7B is
One side surface 73B of the fixing member main body 70B formed in a plate shape having substantially the same overall length in the longitudinal direction as the light guide member 1 and the second light guide member 2 is provided at appropriate intervals in the longitudinal direction. This is provided with a plurality of projections 71B.

As shown in FIG. 5, the second fixing member 7B inserts each of the projections 71B into each of the through holes 83b of the first light reflection plate 8A, and inserts the distal end thereof. The first light-guiding member 1 is attached to the first light-guiding member 1 by further fitting into the holes 18. By the attachment of the second fixing member 7B, a predetermined area of the first light reflecting plate 8A is moved to one side portion 7 of the fixing member main body 70B.
3B, the third side surface 10 of the first light guide member 1
C is adhered. In this case, the first light reflecting plate 8A is formed by the upper surface 73C of the fixing member main body 70B.
May be brought into close contact with a part of the second side surface 20B of the second light guide member 2. The fixing member main body 70B
Is the first light guide member 1 covered by the first light reflection plate 8A.
The first light-reflecting plate 8A is formed into a shape and a size that can be fitted into the space S2 on the other side, which can occur when the first light-reflecting plate 8A and the second light-guiding member 2 are accommodated inside the casing 4. Therefore, when the second fixing member 7B is arranged at a predetermined position in the casing 4, the first light guide member 1
The gap (gap S2) that causes rattling of the second light guide member 2 can be filled by the second fixing member 7B.

4 to 7, the selfoc lens array 51 converges light reflected from a region along the read line L of the original G placed on the image reading surface 53, and makes the light reflected by the read line L. The image sensor chip 52 on the circuit board 6 erects an image along the erecting unit.
This is for forming an image. A plurality of light receiving elements are integrally formed on the main surface of the image sensor chip 52, and are necessary for reading an image at a predetermined reading density by the plurality of image sensor chips 52 arranged in tandem. An appropriate number of light receiving elements are formed in a line.

In the present invention, the selfoc lens array 51 and the image reading surface 53 on the cover glass 4A are
It is characterized by a positional relationship with the main surface of the image sensor chip 52, which will be further described later.

The LEDs 3 (3A to 3C) include R
Chip-shaped LEDs that emit light of each color (red), G (green), and B (blue) are used. Each of the LEDs 3 is the first
The light guide member 1 is mounted on the surface of the circuit board 6 so as to be located in the recess 16. Also, the sequence is the first
The light guide members 1 are arranged in a line in the width direction.

The circuit board 6 is made of, for example, glass epoxy or ceramics, and has a surface provided with a wiring pattern (not shown) for mounting the large number of image sensor chips 52 and one set of LEDs 3. ing. As is well shown in FIG. 5, the circuit board 6 includes:
The casing 4 is fitted into the concave portion 46 provided at the bottom of the casing 4 from below the casing 4. Each of the two attachments 69, 69 is for attaching the circuit board 6 to the casing 4, is fitted to the casing 4 from below, and is provided on the left and right outer surfaces of the casing 4. The hooking of the engagement projections 48 prevents the circuit board 6 from dropping downward. Each of the attachments 69 is formed by, for example, pressing a thin metal plate, and exhibits appropriate elasticity.

In the contact type color image sensor A, as shown in FIG. 6, the first light guide member 1, the second light guide member 2, the first light reflection plate 8A, the first fixing member 7A, and the Each part of the two fixing members 7B can be assembled integrally. That is, the first light guide member 1 and the second light guide member 2 can be connected to each other by the fitting action of the convex portion 23 and the concave portion 19. The first light guide member 1 and the second
After covering a predetermined outer surface area of the light guide member 2 with the first light reflecting plate 8A, the projections 71A and 71B of the first fixing member 7A and the second fixing member 7B are connected to the through holes 8 of the first light reflecting plate 8A.
3a and 83b, and the hole 2 of the second light guide member 2
7 and the hole 18 of the first light guide member 1, the above members can be assembled integrally.

The assembly of the components relating to the light source device as described above is integrally inserted into the casing 4 to complete the assembly of the contact type color image sensor A. Then, the protrusion 29 of the second light guide member 2
The positioning and fixing of the first fixing member 7 and the concave portion 40 of the casing 4 are achieved by the fitting operation of the first fixing member 7 and the first fixing member 7.
Since A and the second fixing member 7B fill the predetermined gaps S1 and S2 in the casing 4, the positioning and fixing of the first light guide member 1 or the second light guide member 2 becomes more reliable.

The through holes 83a and 83b and the hole 2
Each of the projections 71 and 18 has a long hole shape extending in a predetermined direction. Therefore, even if a slight dimensional error occurs in the formation position, the projections 71A and 71B can be appropriately fitted to them. is there. When assembling the second fixing member 7B to the first light guide member 1, if there is a possibility that the projection 28 of the second light guide member 2 and the second fixing member 7B may interfere with each other, By providing a concave portion 75 in the fixing member 7B in advance and making a part of the second fixing member 7B thin,
It is possible to assemble the fixing member 7B efficiently.

Therefore, at the time of assembling and manufacturing the contact type color image sensor A, the predetermined components of the light source device may be integrally assembled and inserted into the casing 4 as described above. It will be. In this case, as shown in FIG. 6, the edge portion 74a at the lower end of the first fixing member 7A and the edge portion 74b at the lower end of the second fixing member 7B are chamfered in a tapered shape.
By providing a and 76b, the operation of inserting the component into the casing 4 can be performed smoothly. Such an effect can also be expected by providing the chamfered portion 76c in the casing 4 at a portion corresponding to the edge portion 74b of the second fixing member 7B, for example.

When the parts of the light source device are inserted into the casing 4, the projections 29 of the second light guide member 2
The positioning and fixing can be achieved by the fitting action between the housing 4 and the recess 40 of the casing 4. In addition, the first fixing member 7A and the second fixing member 7B fill predetermined gaps S1 and S2 in the casing 4. As a result, the positioning and fixing of the first light guide member 1 and the second light guide member 2 become more reliable. Therefore, the components of the light source device can be accurately positioned and held in the casing 4 without necessarily fixing the components with an adhesive or the like. It is possible to arrange them at appropriate positions in relation to each other.

In the above configuration, the image reading surface 53
The color image located on the reading line L of the original G conveyed in close contact is divided into C color component, M color component, and Y color component, and the LEDs 3A, 3B, and 3C of three colors are sequentially turned on.
The image is read by the image sensor chip 52. That is, when the R color LED 3A is turned on, the C color component image is lighting the G color LED 3B, the M color component image is turning on the B color LED 3C,
Images of the Y color component are read. Such a reading operation is repeated for each line in the main scanning direction while transporting the original G in the sub-scanning direction.

Incidentally, the contact type color filter according to the present invention is described.
In the image sensor A, the selfoc lens 51
Image reading surface 53 on cover glass 4A and circuit board
6, the main surface of each image sensor chip 52 (the light receiving element is
Light of the SELFOC lens 51 between the
The axial positional relationship is set as follows. Sand
That is, as described above, the present invention provides a color image sensor.
Therefore, the three primary colors of light are used as the light source in the light source device.
R, G, and B light emitting LEDs 3A, 3B, 3C
Is used, the intermediate wavelength range between R and G, ie,
For example, the above-mentioned Selfoc lens 5 for orange light
The image reading surface 53 and the self
Phases of occ lens 51 and image sensor chip 52
The correlation position is set. That is, in FIG.
The director TC is the TC for orange light.
As can be seen, the first focal position defined by this TC
Place F ₁The image reading surface 53 has a second focal position F_TwoTo
The main surface of the image sensor chip 52 is positioned
Can be

As described above, the refraction characteristics of light differ depending on the wavelength range. As for the SELFOC lens 51, light having a shorter wavelength (for example, blue or purple) has a shorter conjugate length TC, and light having a longer wavelength (for example, red) has a longer conjugate length TC. Since the focal position is determined by the conjugate length TC, the resolution of the image read by the image sensor chip 52 decreases as the image reading surface 53 and the main surface of the image sensor chip 52 deviate from the respective focal positions.

[0068] As described previously with reference to FIG. 1, the nominal conjugate length TC ₀ is certain SELFOC lens 9.1 mm, R color light, the conjugate length TC of the G color light and the B color light, respectively 9.6mm, 8.8mm, 8.5
mm, and there is a maximum difference of 1 mm or more in the air distance between them. In the present invention, the positional relationship between the image reading surface 53, the selfoc lens 51, and the image sensor chip 52 is not set in accordance with the conjugate length of any of these R, G, and B light sources, but R The setting is made in correspondence with the conjugate length of the intermediate color between the color and the G color.
For example, the conjugate length TC of the selfoc lens for orange light is approximately 9.2 mm. Of course, the TC is because the distance in the air, such as the embodiment depicted in FIG. 4, the first focus position F ₁ of the SELFOC lens 51 is formed by the surface of the glass cover 4A having a predetermined thickness, and If the second light guide member 2 exists between the selfoc lens 51 and the glass cover 4A, the image reading surface 53 is read from the selfoc lens 51 in consideration of the refractive index of these members. It goes without saying that the distance to is determined.

Referring to FIG. 1, when TC = 9.2 mm, the resolving power for R-color light and the resolving power for G-color light slightly decrease from the maximum value (65%), but are maintained at high levels. On the other hand, the resolving power for the B color light is reduced to about 37%. However, this has almost no adverse effect on the reading quality of the color image.

That is, as described above, the R color light is the C color component on the read document, the G light is the M color component, and the B light is the Y color component.
Used as a light source for reading color components. The image of the C color component, the image of the M color component,
The color image is reproduced by being superimposed on the image of the Y color component. However, since the Y color is a weak color, even if the Y color image has a slightly reduced resolution, that is, the image is slightly blurred. Even if the resolution of the C-color image and the M-color image is maintained at a predetermined level or more, the resolution of the final color image does not decrease visually.

In the present invention, as described above, the self-contact lens having a relatively short rod lens length is used to hermetically seal the contact-type color image sensor which does not substantially lower the read image quality. . Also,
Selfoc lenses with a short rod lens length have good light transmission efficiency, so that a predetermined reading performance can be achieved without increasing the output of the light source beyond a predetermined value,
In the embodiment shown in the figure, since the above-described configuration is adopted as the light source device, as described below, one LED 3 is provided at an intermediate portion in the longitudinal direction of the casing 4.
Despite the arrangement of A, 3B, and 3C, it is possible to efficiently irradiate a sufficient amount of light while averaging light at various locations in the longitudinal direction of the image reading surface 53.

That is, the three-color LEDs 3A, 3B, 3C
When any one of them emits light, as described with reference to FIG.
Light entering the inside at an appropriate spread angle travels toward both ends in the longitudinal direction of the first light guide member 1 while repeating total reflection, and is dispersed. In the course of such light, the inclined surface 14 of the concave portion 14 of the second side surface 10B is formed.
The light arriving at a is suddenly changed its course and is incident on the first side surface 10A at an angle smaller than a predetermined total reflection critical angle, so that the light exits from the first side surface 10A to the outside. Will be done. When light travels inside the first light guide member 1, each side surface 1 of the first light guide member 1
When light is incident on 0A to 10D at an angle smaller than the predetermined total reflection critical angle, the light is transmitted to the outside of the first light guide member 1 as it is. However, the side faces 10B to 10D other than the first side face 10A of the first light guide member 1 and the end faces 10E and 10F are the first face.
Since the light is covered by the light reflecting plate 8A, such transmission of light is appropriately prevented. Therefore, the first light guide member 1 efficiently guides light to the entire length region in the longitudinal direction, and emits a large amount of light in a band shape from various parts of the entire length region of the first side surface 10A.

Next, the light emitted from the first side surface 10A enters the inside of the second light guide member 2 from the light incident portion 25, and is thereafter reflected by the third side surface 20C and the fourth side surface 20D. The light is emitted from a partial area of the first side surface 20A and guided to the image reading surface 53. In this case, a part of the outer surface of the second light guide member 2 is also used as the first light reflecting plate 8.
Since the light is covered by A, it is possible to prevent light incident on the inside of the second light guide member 2 from leaking to other parts in the casing 4 as much as possible. Therefore, most of the light emitted from the first side surface 10A of the first light guide member 1 is efficiently guided to the image reading surface 53, and the illuminance of the image reading surface 53 can be increased. Since the first fixing member 7A and the second fixing member 7B located outside the first light reflecting plate 7A are white, which is hard to transmit light, the first fixing member 7A and the second fixing member 7B may temporarily transmit light through the first light reflecting plate 8A. This light can be reflected by the first fixing member 7A and the second fixing member 7B to the inside of the first light guide member 1 and the second light guide member 2 to prevent light leakage more thoroughly. It is possible to In particular, the protrusions 71A of the first fixing member 7A and the second fixing member 7B,
Since 71B is opaque white, for example, light traveling inside the first light guide member 1 and the second light guide member 2 is appropriately prevented from leaking to the outside through the projections 71A and 71B. Can be done.

On the other hand, although the first light guide member 1 causes the light emitted from the LED 3 to travel in the longitudinal direction,
There is a tendency that the amount of light emitted from the formation region S of the concave portion 11 of the first side surface 10A facing the LED 3 is larger than the amount of light emitted from other regions of the first side surface 10A. However, most of the light emitted from the concave portion 11 is blocked and scattered and reflected by the light-shielding plate portion 72 located above the concave portion 11, so that the light incident portion 25 starts from the portion facing the concave portion 11. 2 The amount of light entering the light guide member 2 can be reduced. Therefore, it is possible to suppress the light from being intensively incident on the specific portion of the light incident portion 25, and to appropriately uniform the light amount distribution in the longitudinal direction of the reading line on the image reading surface 53. The light shielding plate 72
By scattering and reflecting the light emitted from the first side surface 10A, an effect of dispersing the light to the longitudinal end side of the first light guide member 1 is also exerted. Therefore,
It is possible to more reliably prevent light from intensively entering a specific portion of the light incident portion 25. Since the plurality of light shielding plate portions 72 are provided at appropriate intervals, by changing the size and number of the intervals,
The uniformity of the light amount distribution can be set to an optimal state.

The light incident on the second light guide member 2 is reflected by the third side surface 20C and the fourth side surface 20D located at a predetermined distance from each other, and then guided to the image reading surface 53. In addition, it is possible to increase the optical distance from the first side surface 10A to the image reading surface 53. That is, even when the first light guide member 1 is provided relatively close to the image reading surface 53, it is possible to increase the optical distance of the light emitted to the image reading surface 53. Become. If the optical distance is increased, the variation in the amount of emitted light in the longitudinal direction of the first side surface 10A can be reduced along the optical path. Therefore, even with this,
It is possible to reduce variations in illuminance in the longitudinal direction of the reading line of the image reading surface 53. Further, in the present embodiment, since the fourth side surface 20D is a diffuse reflection surface that scatters and reflects light, the variation in the amount of light in the longitudinal direction of the second light guide member 2 is further reduced by the scatter reflection, and the image reading surface is reduced. It is possible to more completely reduce the variation in the illuminance in the longitudinal direction of the 53 reading lines.

Of course, the scope of the present invention is not limited to the above embodiment. In particular, in the above embodiment, one R, G and B light source is used, While the reading line L
The light source device including the first light guide member and the second light guide member is configured to achieve illumination averaged in the longitudinal direction of the light source device. is not. The main part of the invention of the present application is, in a contact type color image sensor using three color light sources of R, G, and B, a self-focusing lens, which describes a positional relationship among an image reading surface, a selfoc lens, and a light receiving element. Is set as described above in relation to the conjugate length of In the embodiment shown in the figure, the light guide member is interposed between the image reading surface and the selfoc lens. However, in addition to the conventional general structure shown in FIG. The idea of the present invention can also be applied to a case where, for example, a mirror is arranged in the optical path leading to the Fock lens.

[Brief description of the drawings]

FIG. 1 is a graph for explaining the operation of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a Selfoc lens.
(a) is a conventional one generally used for monochrome, and (b) is a commonly used one for color.

FIG. 3 is a sectional view of a main part showing an example of a contact type color image sensor according to the present invention.

FIG. 4 is a sectional view taken along line X1-X1 in FIG. 3;

FIG. 5 is a sectional view taken along line X2-X2 in FIG. 3;

FIG. 6 is a cross-sectional view showing a state in which the contact type color image sensor shown in FIG. 3 is assembled.

7 is an exploded perspective view of the contact type color image sensor shown in FIG.

FIG. 8 is a front view showing an example of a first light guide member.

FIG. 9 is a plan view illustrating an example of a first light guide member.

FIG. 10 is a sectional view taken along the line X3-X3 in FIG.

FIG. 11 is a sectional view taken along line X4-X4 in FIG. 8;

FIG. 12 is a sectional view taken along line X5-X5 in FIG. 8;

FIG. 13 is an explanatory diagram showing an operation of the first light guide member.

FIG. 14 is an explanatory view of a main part showing another example of the first light guide member.

FIG. 15A is a plan view illustrating an example of a second light guide member,
(b) is a front view thereof.

FIG. 16 is a sectional view taken along line X6-X6 in FIG.

FIG. 17 is a sectional view taken along the line X7-X7 in FIG. 15 (b).

18 (a) is a plan view showing an unfolded state of the first light reflecting plate, FIG. 18 (b) is a sectional view taken along line X8-X8 in FIG. 18 (a), and FIG. FIG. 10 is a sectional view taken along line X9-X9 in FIG.

FIG. 19 is a perspective view showing a state where the first light reflection plate is assembled in a three-dimensional shape.

FIG. 20A is a plan view illustrating an example of a first fixing member,
(b) is a front view thereof.

FIG. 21 is a sectional view taken along line X10-X10 in FIG. 20 (b).

FIG. 22 is a sectional view taken along the line X11-X11 in FIG.

FIG. 23 (a) is a front view showing an example of a second fixing member,
(b) is a sectional view taken along line X12-X12 of (a), (c)
FIG. 3A is a cross-sectional view taken along line X13-X13 of FIG.

FIG. 24 is a cross-sectional view illustrating an example of a conventional contact image sensor.

[Explanation of symbols]

 A contact type color image sensor 3 light source 3A, 3B, 3C R, G, B light emitting LED 4 casing 4A cover glass 6 circuit board 51 selfoc lens array 52 image sensor chip (light receiving element) 53 image reading surface TC conjugate length G reading Original L Read line

Claims (5)

[Claims] 1. An image reading surface on which a document to be read is conveyed in close contact, a plurality of light receiving elements arranged in a line, and an R for illuminating the document to be read on the image reading surface.
A contact type color image sensor comprising: G and B light sources; and a selfoc lens disposed between the image reading surface and the light receiving element for focusing an image of a read document on the image reading surface onto the light receiving element. Wherein a positional relationship between the selfoc lens, the image reading surface, and the light receiving element is defined corresponding to a conjugate length of the selfoc lens for an intermediate wavelength range between R and G. A contact type color image sensor. 2. An image reading surface on which a document to be read is conveyed in close contact, a plurality of light receiving elements arranged in a line, and R for illuminating the document to be read on the image reading surface.
A contact type color image sensor comprising: G and B light sources; and a selfoc lens disposed between the image reading surface and the light receiving element for focusing an image of a read document on the image reading surface onto the light receiving element. Wherein the image reading surface is disposed at a first focal position of the selfoc lens and the light receiving element is disposed at a second focal position of the selfoc lens for an intermediate wavelength range between R and G, respectively. A contact type color image sensor. 3. An image reading surface formed by a casing, a surface of a transparent cover glass attached to one surface side of the casing, and on which an original to be read is closely transported.
A plurality of light receiving elements arranged in a line on a main surface of a plurality of image sensor chips mounted on a substrate mounted on the other surface side of the casing, and provided on the image reading surface provided in the casing. R, G, and B light sources for illuminating an original to be read, and a cell disposed between the image reading surface and the light receiving element for focusing an image of the read original on the image reading surface to the light receiving element A contact type color image sensor comprising a Foc lens, wherein a positional relationship between the selfoc lens, the image reading surface, and the light receiving element is such that the selfoc lens for an intermediate wavelength range of R and G And the distance between the image reading surface and the light receiving element is set to 12 mm or less. A contact type color image sensor. 4. The R, G, and B light sources are mounted on the substrate, and a light guide member for guiding light emitted from the light source to the image reading surface is provided in the casing. The contact type color image sensor according to claim 3, wherein 5. The R, G, and B light sources each have one point light source disposed at a central portion in the longitudinal direction of the substrate.
5. The light guide member according to claim 4, wherein the light emitted from the R, G, and B light sources is configured to be dispersed and emitted to a region extending in a longitudinal direction of the casing on the image reading surface. The contact type color image sensor described in the above.