JP2000349957A - Color image sensor and image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color image sensor that efficiently and uniformly leads light from a light source a read face. SOLUTION: This color image sensor is provided with a prism 21, that is formed to be nearly a sector where an end face 21 at a short-side opposes a white light radiation face 7a of a white light emitting diode 7, an end face 21b of a long-side opposes a read face 23 of a read original, a front face 21f and a rear face 21g placed at both ends in a cross direction have a curved face, in such a way that the white light emitted from the white light emitting diode 7 is collected on the read face 23 of the read original, a semiconductor color sensor 9 that has a plurality of red light receiving sections, blue light receiving sections and green light receiving sections respectively, receives the while light reflected in the read face by each light receiving section to simultaneously output a red read image signal, a blue read image signal and a green read image signal, and a rod lens array 19 that forms an image reflected in the read face to each light receiving section of the semiconductor color sensor 9 as an erect and unmagified image.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image sensor for reading an image on a read document by moving relative to the read document at least in the sub-scanning direction, and an image reading apparatus including the color image sensor.

[0002]

2. Description of the Related Art Among conventional color image sensors, a serial type color image sensor has a wiring board 51, a light emitting diode array 52, a prism 53, a lens 54, a mirror 55, a lens 56, and a wiring board as shown in FIG. 57, a semiconductor monochrome sensor 58, and flexible cables 59 and 60. Then, as shown in FIG. 28, the light emitting diode array 52 includes two green light emitting diodes 52G and two blue light emitting diodes 5G.
2B and one red light emitting diode 52R.

In this conventional serial type color image sensor, red light emitting diodes 52 R, green light emitting diodes 52 G, and blue light emitting diodes 52 B of a light emitting diode array 52 are selectively turned on sequentially, and the light is read by a prism 53 to a reading surface 65. And the reflected light from the reading surface 65 is reduced by the lens
The path is changed, and the light is further reduced by the lens 56 and enters the light receiving surface of the semiconductor monochrome sensor 58. Accordingly, the semiconductor monochrome sensor 58 outputs a read image signal corresponding to the amount of received light to the outside via the wiring board 57, the flexible cable 60, and a connector (not shown). The driving signal of the light emitting diode array 52 is
It is supplied from outside through a connector, a flexible cable 60, a wiring board 57, and a flexible cable 59. The power and various control signals of the semiconductor monochrome sensor 58 are supplied from the outside via a connector, a flexible cable 60, and a wiring board 57.

However, in such a conventional serial type color image sensor, although the prism 53 is provided, its shape has not been sufficiently examined, so that light from the light emitting diode array 52 can be read sufficiently sufficiently. Light could not be collected on the surface 65. In addition, since reading is performed by repeatedly turning on the red light emitting diode 52R, the green light emitting diode 52G, and the blue light emitting diode 52B sequentially, there is a problem that the reading speed is low. In addition, there is a problem that banding is likely to occur due to the temperature characteristics of the red light emitting diode 52R. Furthermore, because of the adoption of the reduction optical system,
Banding is likely to occur due to image distortion of the lenses 54 and 56, and there has been a problem that high assembly accuracy is required to reduce this problem. In addition, since the structure is complicated and the number of parts is large, there is a problem that parts costs and assembly costs are high.

On the other hand, among the conventional color image sensors, a contact type line color image sensor includes:
There is known a configuration in which a transparent long light guide is provided, light from a light source is incident on an end face of the light guide, and the light is guided to a reading surface.

However, in such a conventional contact-type line color image sensor, it is difficult to guide the light from the light source to the reading surface with sufficient efficiency and uniformity. In this case, the shape of the light guide becomes complicated, and high precision is required for manufacturing, so that the cost of parts increases.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been devised in view of the above circumstances, and provides a color image sensor and an image reading apparatus capable of efficiently and uniformly guiding light from a light source to a reading surface. The task is to provide.

In order to solve the above problems, the present invention provides:
The following technical measures have been taken:

According to a first aspect of the present invention, there is provided a color image sensor for reading an image on a read document by moving at least in a sub-scanning direction with respect to the read document, the white light emitting diode emitting white light. The front and back faces are substantially fan-shaped, with the short side end face facing the white light emitting surface of the white light emitting diode, the long side end face facing the reading surface of the document to be read, and located at both ends in the thickness direction. However, a prism having a curved surface shape that condenses the white light emitted from the white light emitting diode on the reading surface of the read document, a light receiving portion for red, a light receiving portion for blue, and a light receiving portion for green are provided. And a semiconductor color sensor that outputs a red read image signal, a blue read image signal, and a green read image signal simultaneously by receiving white light reflected on the reading surface by each light receiving unit. , The white light reflected by up surface, in the light receiving portions of the semiconductor color sensor, characterized by comprising a lens for forming in erecting, color image sensor.

According to a preferred embodiment, the white light emitting diode, the prism, and the semiconductor color sensor each include one.
The image reading unit reads the image on the read original by moving relative to the read original in both the main scanning direction and the sub-scanning direction.

According to another preferred embodiment, the lenses are rod lens arrays.

According to another preferred embodiment, the lens is a pair of convex lens arrays arranged continuously in the optical axis direction.

According to another preferred embodiment, the white light emitting diode and the semiconductor color sensor are mounted on the same wiring board.

According to another preferred embodiment, the wiring substrate, the prism, and the lens are incorporated in a frame, and the frame includes a pair of first opposing surfaces opposing both end surfaces of the wiring substrate, and a white light emitting surface. 1 facing both ends of the diode
A pair of second opposing surfaces, a gap between the second opposing surface and both end surfaces of the white light emitting diode is set smaller than a gap between the first opposing surface and both end surfaces of the wiring board, The position of the white light emitting diode is regulated by the second facing surface, thereby positioning the wiring board.

According to another preferred embodiment, a transparent cover is provided between the prism and the lens and the reading surface, and the cover is formed integrally with the prism.

According to a second aspect of the present invention, there is provided an image reading apparatus having the color image sensor according to claim 2, wherein the semiconductor color sensor comprises a red light receiving section, a blue light receiving section, and a green light receiving section. The light receiving units of the same color are arranged in a line at a first predetermined pitch in the main scanning direction, with the light receiving units for use in the main scanning direction spaced apart from each other by a predetermined distance in the sub-scanning direction. Sub-scanning direction driving means for relatively reciprocating the sensor and the sub-scanning direction at a second predetermined pitch;
A main scanning direction in which the read document and the color image sensor are relatively moved in the main scanning direction at a third predetermined pitch at the end of one forward movement and one end of one backward movement by the sub-scanning direction driving means. The driving means and the read image signals of the respective colors output from the semiconductor color sensor are arranged such that a red read image signal, a blue read image signal, and a green read image signal of the same pixel on the read document become one set. An image reading apparatus is provided, comprising: an image processing unit that ignores a read image signal of a line in which one or more of the three colors cannot be obtained in combination.

According to the present invention, the prism is substantially fan-shaped, with the short side end face facing the white light emitting surface of the white light emitting diode, and the long side end face facing the reading surface of the document to be read. Since the front and back located at both ends in the thickness direction are formed into a curved shape so as to converge the white light emitted from the white light emitting diode on the reading surface of the read original, the white light from the white light emitting diode can be efficiently emitted. In addition, the light can be uniformly collected on the reading surface.

[0018] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0019]

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

FIG. 1 is a plan view of a serial type color image sensor as an example of a color image sensor according to the present invention, FIG. 2 is a front view thereof, FIG. 3 is a right side view thereof, and FIG.
Is a left side view, FIG. 5 is a bottom view, and FIG. 6 is a rear view. FIG. 7 is a cross-sectional view taken along the line AA of FIG. 2, and a wiring board 3 is mounted on the lower surface of the frame 1 of the serial type color image sensor. A glass plate 5 is mounted on the upper surface of the frame 1. On the wiring board 3, a white light emitting diode 7 as a light source for reading a read document and a semiconductor color sensor 9 for outputting read image signals of red, green, and blue corresponding to the image of the read document are mounted. And the clip connector 11 is attached.

The frame 1 has a light guide hole 13 extending from the upper surface of the wiring board 3 to the lower surface of the glass plate 5, and a through hole extending from the lower surface of the glass plate 5 to the upper surface of the wiring substrate 3 adjacent to the light guide hole 13. A hole 15 and bolt holes 17a and 17b for assembling each component of the frame 1 are formed. The upper half portion of the light guide hole 13 and the through hole 15 communicate with each other. A rod lens array 19 is mounted in the upper half of the through hole 15. The upper end surface of the rod lens array 19 is close to the lower surface of the glass plate 5. A prism 21 is provided in the light guide hole 13. The white light emitting diode 7 is located at the lower end of the light guide hole 13, and the semiconductor color sensor 9 is located at the lower end of the through hole 15. The lower end surface of the prism 21 is close to the white light emitting surface 7a of the white light emitting diode 7, and the upper end surface of the prism 21 is close to the lower surface of the glass plate 5.

Each component of the frame 1 is made of black resin. The dimensions of the frame 1 in the present embodiment are shown in FIG.
And as shown in FIG. 2, the length is 19 mm and the width is 16 m
m, height is 17.2 mm. White light emitting diode 7
For example, a GaN-based white light emitting diode having a phosphor layer or a ZnSe-based white light emitting diode having no phosphor layer can be used.

FIG. 8 is a plan view of the wiring board 3, on which passive components 25 and 27 are mounted in addition to the white light emitting diode 7 and the semiconductor color sensor 9. The wiring board 3 is further provided with a plurality of terminals 29.

FIG. 9 is an enlarged plan view of the semiconductor color sensor 9. On the surface of the semiconductor color sensor 9, a red light receiving portion 31R, a green light receiving portion 31G, and a blue light receiving portion 31B are provided. Are formed in plurality. The light receiving units 31R, 31G, and 31B are arranged in a row at a predetermined pitch P along the main scanning direction, that is, the longitudinal direction of the semiconductor color sensor 9 for each color. And the light receiving unit 3
The interval between 1R and the light receiving portion 31G and the interval between the light receiving portion 31G and the light receiving portion 31B are 2P, which is twice the pitch P. Each of the light receiving sections 31R, 31G, and 31B has a structure in which the light receiving surface of the photodiode is covered with a color filter. The semiconductor color sensor 9 includes, in addition to the photodiode described above,
A field effect transistor for outputting electric charges accumulated in each photodiode, a shift register for sequentially turning on the field effect transistors, and the like are provided. In the present embodiment, the light receiving units 31R, 31G, 31B
Are provided, each of which corresponds to a reading density of 600 dpi.

FIG. 10 is a front view of the prism 21 and FIG.
Is a plan view, FIG. 12 is a right side view, FIG. 13 is a left side view, FIG. 14 is a rear view, and FIG. 15 is a bottom view. The prism 21 is substantially fan-shaped and has an end surface 21a on the short side.
Are opposed to the white light emitting surface 7 a of the white light emitting diode 7, and the end surface 21 b on the long side is opposed to the reading surface 23. The prism 21 has a pair of protrusions 21c and 21d integrally protruding at both ends of an upper end portion of the front, and a single protrusion 21e integrally protruding at the center of the rear surface. These protrusions 21c, 21d, 21e are used for positioning and holding the prism 21 with respect to the frame 1, as shown in FIG.

FIG. 16 is an explanatory view of the optical path of white light passing through the prism 21 as viewed from the side of the prism 21. FIG.
Represents the optical path of white light passing through the prism 21
FIG. 2 is an explanatory diagram viewed from the front side of FIG. As is clear from FIG. 16, the front surface 21 f and the rear surface 21 g located at both ends in the thickness direction of the prism 21 are formed into a curved surface shape such that the white light emitted from the white light emitting diode 7 is condensed on the reading surface 23. ing. That is, the front surface 21f and the back surface 21g of the prism 21 reflect white light traveling from the inside of the prism 21 toward the outside toward the inside of the prism 21 at the front surface 21f or the back surface 21g, and the reading surface 2
3 is formed in a curved surface. FIG.
As can be seen from FIG. 2, both side surfaces 21h and 21i along the radial direction of the prism 21 are provided with white light traveling from the inside of the prism 21 to the outside.
The light is reflected to the inside of the prism 21 by i, and is formed on a flat surface facing the reading surface 23. Therefore, FIG.
As shown in FIG. 8, the amount of white light passing through the prism 21 and irradiating the read document becomes substantially uniform over the entire reading width.

FIG. 19 is an enlarged sectional view of the bottom of the color image sensor. In FIG. 19, the clip connector 11 is omitted for easy understanding. The frame 1 includes a pair of first opposing surfaces 1a and 1b facing both end surfaces 3a and 3b of the wiring board 3, and a pair of second opposing surfaces 1c and 1a facing both end surfaces 7b and 7c of the white light emitting diode 7. 1d. A gap C1 between the end face 7b of the white light emitting diode 7 and the second facing face 1c of the frame 1,
The total C1 + C2 of the gap C2 between the end face 7c of the white light emitting diode 7 and the second facing face 1d of the frame 1 is the gap C between the end face 3a of the wiring board 3 and the first facing face 1a of the frame 1.
3 and a gap C4 between the end face 3b of the wiring board 3 and the first opposing face 1b of the frame 1 is smaller than the total C3 + C4.

Next, the operation will be described. The white light emitted from the white light-emitting diode 7 passes through the prism 21 and the glass plate 5 and irradiates the reading surface 23 of the read document. At this time, the white light from the white light-emitting diode 7 is favorably condensed on the reading surface 23 by the prism 21 and has a substantially uniform light amount distribution over the entire reading width. Therefore, the white light from the white light emitting diode 7 is uniformly guided to the reading surface 23 without any loss, and the reading surface
Irradiate 3.

The white light reflected on the reading surface 23 of the read original passes through the glass plate 5 and is incident on the rod lens array 19, is condensed by the rod lens array 19, and is received by the light receiving sections 31R and 31G of the semiconductor color sensor 9. , 31B. At this time, the rod lens array 19 forms an image on the reading surface 23 of the read document on the surface of the semiconductor color sensor 9 at an erect equal magnification.

When white light is incident on the light receiving sections 31R, 31G, and 31B, the semiconductor color sensor 9 causes the red read image signal and the green read image signal corresponding to the amount of light incident on the light receiving sections 31R, 31G, and 31B. And the blue read image signal. Of course, the read image signals of each color are received by the light receiving units 31R, 31 arranged at the pitch P in the main scanning direction.
It is sequentially output for each pixel corresponding to G and 31B.

At this time, the read original is stationary. Then, the read original is fed by the pitch P in the sub-scanning direction, and the next line is read.

By repeating the above operation, a portion corresponding to the reading width of the serial type color image sensor in one page of the read document is read over all the lines.

Thereafter, the serial type color image sensor is moved in the main scanning direction by a distance corresponding to the reading width, and each line is read. At this time, the read original is sent in the reverse direction along the sub-scanning direction.

By repeating the above operation, the reading of one page of the read document is completed.

That is, as shown in FIG.
In the cycle of sec, the read image signal of each color corresponding to one line of the read width of the serial type color image sensor is output. The output of the read image signal of each color is performed in synchronization with a clock signal of a predetermined cycle.
A read image signal of each color corresponding to 304 pixels is output during the period of msec. Each time the serial type color image sensor moves in the main scanning direction, the drive voltage of the white light emitting diode 7 is adjusted and the charge accumulated in the photodiode of the semiconductor color sensor 9 is discharged for 2.5 msec.

By the way, when the read original is sent in the direction of arrow B in FIG.
Assuming that reading is started when light is received at R, as shown in FIG. 21, in reading at the first time t _1, a red read image signal of the first line and a green read image signal of the third line And the blue read image signal of the fifth line are output from the semiconductor color sensor 9. In reading at the next time t ₂ , the red color read image signal of the second line, the green color read image signal of the fourth line, and the blue color read image signal of the sixth line are output from the semiconductor color sensor 9. . In the reading at the next time t _3, a red read image signal of the third line, a green read image signal of the fifth line, and a blue read image signal of the seventh line are output from the semiconductor color sensor 9. . In the reading at the next time t _4, a red read image signal of the fourth line, a green read image signal of the sixth line, and a blue read image signal of the eighth line are output from the semiconductor color sensor 9. . Similarly, in the read image signals of the respective colors that are simultaneously read, the read image signal of red and the read image signal of green are shifted by two lines, and the read image signal of green and the read image signal of blue are shifted by two lines. It is out of alignment. This is because the light receiving unit 31R and the light receiving unit 31G are arranged with a shift of 2P in the sub-scanning direction, and the light receiving unit 31G and the light receiving unit 31B are arranged with a shift of 2P in the sub-scanning direction.

Also, by reversing the feeding direction of the read original,
When the document is fed in the direction opposite to the direction of arrow B in FIG. 9 and the reading is started when the image of the n-th line of the read document is received by the light receiving section 31B, as shown in FIG. In reading at time t _n, a red read image signal of the (n−4) th line, a green read image signal of the (n−2) th line, and a blue read image signal of the nth line are output from the semiconductor color sensor 9. Is done. In reading at the next time t _{n + 1} , the red read image signal of the (n−5) th line, the green read image signal of the (n−3) th line, and the (n−1) th line
The read color image signal of the line and the semiconductor color sensor 9
Output from In the reading at the next time t _{n + 2} , the red read image signal of the (n−6) th line and the (n−4) th
The green color read image signal of the line and the blue color read image signal of the (n-2) th line are output from the semiconductor color sensor 9. In the reading at the next time t _{n + 3} , the red read image signal of the (n−7) th line, the green read image signal of the (n−5) th line, and the blue read image signal of the (n−3) th line are obtained. Output from the semiconductor color sensor 9. Similarly, in the read image signals of the respective colors that are simultaneously read, the read image signal of red and the read image signal of green are shifted by two lines, and the read image signal of green and the read image signal of blue are shifted by two lines. It is out of alignment. This is because the light receiving unit 31R and the light receiving unit 31G are arranged with a shift of 2P in the sub-scanning direction, and the light receiving unit 31G and the light receiving unit 31B are arranged with a shift of 2P in the sub-scanning direction. Also, the reason why the reading line advances from the nth line to the first line with the passage of time is that the read original is sent in the reverse direction.

Therefore, it is necessary to process the read image signals of the respective colors obtained at the same time and to rearrange the read image signals of the respective colors of red, green and blue into a set for each pixel. This process is executed using a buffer memory or the like after A / D conversion of the read image signal of each color from the semiconductor color sensor 9 by the image reading device. At this time, as shown in the read image signals of the first to fourth lines in FIG. 21 and the read image signals of the nth to nth lines in FIG.
A read image signal of a line in which one or more of the blue colors cannot be obtained is discarded because the three colors cannot be combined. That is, it is necessary to determine the reading start position at the time of reciprocation along the sub-scanning direction in consideration of the discarded line. In FIG. 20, the read image signal of the discarded line is displayed as a dummy (Dummy).

As described above, the prism 21 is substantially fan-shaped, the short side end surface 21a faces the white light emitting surface 7a of the white light emitting diode 7, and the long side end surface 21b is the reading surface 2
3, the front surface 21f and the rear surface 21g located at both ends in the thickness direction are formed into a curved surface so as to converge the white light emitted from the white light emitting diode 7 on the reading surface 23. 7 can be efficiently and uniformly converged on the reading surface 23.

The gap C1 between the end face 7b of the white light emitting diode 7 and the second opposing face 1c of the frame 1, the end face 7c of the white light emitting diode 7 and the second opposing face 1d of the frame 1
The sum C1 + C2 of the gap C2 and the gap C3 between the end face 3a of the wiring board 3 and the first facing face 1a of the frame 1 and the gap C4 between the end face 3b of the wiring board 3 and the first facing face 1b of the frame 1 Is smaller than the sum C3 + C4, the variation in the amount of received light in the light receiving sections 31R, 31G, and 31B of the semiconductor color sensor 9 due to the displacement of the white light emitting diode 7 can be reduced as much as possible. That is, as the light-collecting efficiency of the prism 21 increases, the variation in the amount of received light in the light-receiving units 31R, 31G, and 31B of the semiconductor color sensor 9 due to the displacement of the white light-emitting diode 7 increases. C3 + C4
By making the size smaller than that, the relative positional relationship between the prism 21 and the white light emitting diode 7 can be properly maintained irrespective of the displacement of the mounting position of the white light emitting diode 7 on the wiring board 3. 9
Thus, variations in the amount of received light in the light receiving units 31R, 31G, and 31B can be reduced as much as possible. This is, in particular,
This is effective when the change in the amount of light due to the displacement of the white light emitting diode 7 is larger than the change in the amount of light due to the displacement of the semiconductor color sensor 9.

Further, since one white light emitting diode 7 is used as the light source, the manufacturing cost can be reduced by reducing the number of parts, as compared with the case of using red, green and blue light emitting diodes. . Moreover, there is no problem caused by the combination of the individual differences in the emission wavelength of the light emitting diodes of each color. Furthermore, banding due to the temperature characteristics of the red light emitting diode does not occur.

Further, since the semiconductor color sensor 9 for simultaneously outputting the red read image signal, the blue read image signal, and the green read image signal is used, the read image signal is compared with the case where a monochrome color sensor is used. Speed can be increased.

Further, since the erecting equal-magnification type rod lens array 19 is used for the image forming optical system, banding can be reduced as compared with the case where a reduction optical system is employed. Moreover,
Easy assembly.

Since the read original is reciprocated in the sub-scanning direction to perform bidirectional reading, the reading speed can be increased as compared with the case where reading is performed in only one direction.

Further, since the white light emitting diode 7 and the semiconductor color sensor 9 are mounted on the same wiring board 3, the structure can be simplified and the assembly can be performed easily.

In the above embodiment, the rod lens array 19 is used as the lens of the imaging optical system.
As shown in FIG. 23, two convex lens arrays 35a and 35b may be used instead of the rod lens array 19. The convex lens array 35a and the convex lens array 35b are arranged such that their optical axes coincide with each other. In this case, since the expensive rod lens array 19 is not used, component costs can be reduced.

In the above embodiment, the glass plate 5 and the prism 21 are provided independently of each other. However, as shown in FIG. 24, a prism 37 integrated with a glass plate may be provided. By doing so, the assembly cost can be reduced by reducing the number of parts.

In the above embodiment, the frame 1 is made of a black material. However, as shown in FIG. 25, a frame 39 made of a white material may be used. With this configuration, the white light that has jumped out of the prism 21 can be reflected on the wall surface of the frame 1 and returned to the inside of the prism 21 again, so that the light collection efficiency on the reading surface 23 is further improved. However, in this case, by covering the semiconductor color sensor 9 with the black frame 41, it is possible to prevent white light irregularly reflected on the wall surface of the frame 1 from being incident on the light receiving portions 31R, 31G, 31B of the semiconductor color sensor 9 as much as possible. Is preferred. Of course, the frame 41 is provided with a slit for allowing the white light passing through the rod lens array 19 to reach the light receiving portions 31R, 31G, 31B of the semiconductor color sensor 9.

In the above-described embodiment, the clip connector 11 is mounted on the wiring board 3, but a clip pin 43 may be used instead of the clip connector 11 as shown in FIG. In this way, FPC and FF
C can be soldered, and the cost can be reduced.

In the above embodiment, the light receiving section 3
1R, 31G, 31B, the distance between the light receiving unit 3 of the same color
1R, the light receiving portion 31G, or the light receiving portion 31B is set to be twice as large as the pitch P.
This is because the manufacture of the semiconductor color sensor 9 is easier than doubled, and if the manufacture is possible, the light receiving sections 31R, 31R
The interval between G and 31B may be set to one time of the pitch P. Of course, the interval between the light receiving units 31R, 31G, and 31B may be set to three times or more the pitch P.

In the above embodiment, the read original is reciprocated in the sub-scanning direction. However, the serial type color image sensor may be reciprocated in the sub-scanning direction. Good. Or,
The read document and the serial type color image sensor may be configured to reciprocate along the sub-scanning direction and in directions opposite to each other.

In the above-described embodiment, the serial type color image sensor is moved along the main scanning direction. However, the read original may be moved along the main scanning direction. Alternatively, the read document and the serial type color image sensor may be configured to move in opposite directions along the main scanning direction.

In the above embodiment, the serial type color image sensor has been described, but the present invention may be applied to a line color image sensor. That is, a plurality of white light emitting diodes 7 and a plurality of prisms 21 are juxtaposed in the reading width direction, and a plurality of semiconductor color sensors 9 are juxtaposed in the reading width direction in close contact with each other. It almost matches the width.

In the above embodiment, the semiconductor color sensor 9 having a photodiode as a light receiving element is used. However, a semiconductor color sensor having a photo transistor as a light receiving element may be used.

Further, the color image sensor and the image reading device of the present invention can be used not only for an image scanner but also for a digital copier, an ink jet printer or a word processor having multiple functions.

[Brief description of the drawings]

FIG. 1 is a plan view of a serial type color image sensor as an example of a color image sensor according to the present invention.

FIG. 2 is a front view of a serial type color image sensor as an example of a color image sensor according to the present invention.

FIG. 3 is a right side view of a serial type color image sensor as an example of a color image sensor according to the present invention.

FIG. 4 is a left side view of a serial type color image sensor as an example of a color image sensor according to the present invention.

FIG. 5 is a bottom view of a serial type color image sensor as an example of a color image sensor according to the present invention.

FIG. 6 is a rear view of a serial type color image sensor as an example of the color image sensor according to the present invention.

FIG. 7 is a sectional view taken along line AA of FIG. 2;

FIG. 8 is an enlarged plan view of a wiring board.

FIG. 9 is a partially enlarged plan view of the semiconductor color sensor.

FIG. 10 is a front view of a prism.

FIG. 11 is a plan view of a prism.

FIG. 12 is a right side view of the prism.

FIG. 13 is a left side view of the prism.

FIG. 14 is a rear view of the prism.

FIG. 15 is a bottom view of the prism.

FIG. 16 is an explanatory diagram of an optical path of white light passing through a prism, as viewed from a side surface of the prism.

FIG. 17 is an explanatory diagram of the optical path of white light passing through the prism, as viewed from the front side of the prism.

FIG. 18 is an explanatory diagram of a light amount distribution of white light that irradiates a read original through a prism.

FIG. 19 is an enlarged sectional view of the bottom of a serial type color image sensor as an example of the color image sensor according to the present invention.

FIG. 20 is an explanatory diagram of the operation timing of the semiconductor color sensor.

FIG. 21 is an explanatory diagram of lines that are simultaneously read by light receiving units of each color by a relative movement in a forward direction along a sub-scanning direction.

FIG. 22 is an explanatory diagram of lines that are simultaneously read by light receiving units of each color by relative movement in the reverse direction along the sub-scanning direction.

FIG. 23 is a sectional view of a serial type color image sensor according to another embodiment of the present invention.

FIG. 24 is a sectional view of a serial type color image sensor according to still another embodiment of the present invention.

FIG. 25 is a sectional view of a serial type color image sensor according to still another embodiment of the present invention.

FIG. 26 is a sectional view of a serial type color image sensor according to still another embodiment of the present invention.

FIG. 27 is a schematic configuration diagram of a conventional serial type color image sensor.

FIG. 28 is a plan view of a semiconductor sensor provided in a conventional serial type color image sensor.

[Explanation of symbols]

 1, 39 frame 3 wiring board 5 glass plate 7 white light emitting diode 9 semiconductor color sensor 11 clip connector 13 light guide hole 15 through hole 17a, 17b bolt hole 19 rod lens array 21, 37 prism 23 reading surface 27 terminal 31R light receiving section 31G Light receiving unit 31B Light receiving units 35a, 35b Convex lens array 41 Frame 43 Clip pin

Claims (8)

[Claims] 1. A color image sensor for reading an image on a read original by relatively moving at least in a sub-scanning direction with respect to the original to be read, comprising: a white light emitting diode emitting white light; The end face on the side faces the white light emitting surface of the white light emitting diode, the end face on the long side faces the reading surface of the read document, and the front and back surfaces located at both ends in the thickness direction are the white light emitting diode. A prism having a curved surface shape for converging the white light radiated from the document on the reading surface of the read document, and a plurality of light receiving portions for red, blue, and green, respectively. A semiconductor color sensor that outputs a red read image signal, a blue read image signal, and a green read image signal simultaneously by receiving white light reflected by the reading surface by each of the light receiving units. A color image sensor comprising: a lens that forms white light reflected by the reading surface on each of the light receiving units of the semiconductor color sensor at an erect equal magnification. 2. The apparatus according to claim 1, wherein the white light emitting diode, the prism, and the semiconductor color sensor are provided one each, and the white light emitting diode is moved relative to the read original in both a main scanning direction and a sub scanning direction. The color image sensor according to claim 1, which reads an image on a read document. 3. The color image sensor according to claim 1, wherein the lens is a rod lens array. 4. The color image sensor according to claim 1, wherein the lens is a pair of convex lens arrays arranged continuously in an optical axis direction. 5. The color image sensor according to claim 1, wherein said white light emitting diode and said semiconductor color sensor are mounted on the same wiring board. 6. The wiring board, the prism, and the lens are incorporated in a frame, and the frame includes a pair of first facing surfaces facing both end surfaces of the wiring board, and a frame of the white light emitting diode. A pair of second opposing surfaces opposing both end surfaces, and a gap between the second opposing surface and both end surfaces of the white light emitting diode is formed between the first opposing surface and both end surfaces of the wiring board; 6. The color image sensor according to claim 5, wherein the wiring board is positioned by setting the white light emitting diode to be smaller than the gap of the white light emitting diode and the position of the white light emitting diode is regulated by the second facing surface. 7. A transparent cover body is provided between the prism and the lens and the reading surface, and the cover body is formed integrally with the prism. The color image sensor according to any one of the above. 8. An image reading device having the color image sensor according to claim 2, wherein the semiconductor color sensor includes a light receiving unit for red light, a light receiving unit for blue light, and a light receiving unit for green light. However, the light receiving portions of the same color are arranged in a line at a first predetermined pitch in the main scanning direction in a state where they are spaced from each other by a predetermined distance in the sub-scanning direction. A sub-scanning direction driving means for relatively reciprocating at a second predetermined pitch in the sub-scanning direction; and at the end of one forward movement and one end of the backward movement by the sub-scanning direction driving means, Main scanning direction driving means for relatively moving the read document and the color image sensor at a third predetermined pitch in the main scanning direction; and reading the read image signal of each color output from the semiconductor color sensor to the read document. above Combinations red read image signals and the blue of the read image signal takes the same pixel and a green read image signals are formed so that one pair, one of the three colors 1
An image reading apparatus comprising: an image processing unit that ignores a read image signal of a line that cannot obtain more than a color.