JPH1169081A - Sensor ic and image sensor provided with it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow each photodetector to receive a light only in a desired color passing through a filter. SOLUTION: In the sensor IC where pluralities of photodetectors 1 providing an output of a signal in response to a light receiving amount on chip substrates formed rectangular as plane view, a plurality of the photodetectors 1 are arranged on the chip substrates as columns in the main scanning direction and three photodetector arrays are arranged in the subscanning direction. Each photodetector array is respectively covered with three kinds of filters that transmit through red, green and blue colors respectively as the red, green and blue photodetector arrays 10R, 10G, 10B, and the surrounding of each color photodetector array is formed to be a light shield through which no light is transmitted. Preferably the light shield part is formed by overlapping at least two kinds among the three kinds of filters 7R, 7G, 7B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image sensor used in an image reading unit or an image scanner of a facsimile apparatus, and a sensor IC used in the image sensor.

[0002]

2. Description of the Related Art As is well known, an image reading apparatus that reads a document in color emits white light from a light source to the surface of the document, and then reflects the reflected light for a red light, a green light, And three types of light receiving elements for blue light. The three types of light receiving elements individually detect the amounts of red light, green light, and blue light, and output signals corresponding to the amounts of received color light.

For example, in an image reading apparatus configured to read an image of a document for each line, it is necessary to arrange a plurality of the three types of light receiving elements on the sensor IC in the main scanning direction. Therefore, conventionally, FIG.
As shown in FIG. 3, the light receiving elements 8R for red light, the light receiving elements 8G for green light, and the light receiving elements 8B for blue light are arranged in a line in the main scanning direction such that each of the light receiving elements is repeatedly arranged in a predetermined order. Was arranged in a row. In such a configuration, a total of three light receiving elements 8R, 8G, and 8B for each color constitute one set, and this set is responsible for reading an image of one pixel.

However, in the above-described configuration, a total of three light receiving elements 8R, 8G, and 8B are used to read one pixel of an image. The width S1 of the light receiving elements 8R, 8G, 8B in the main scanning direction must be equal to or less than 1/3 of the width S2 of one pixel. For example, when a read original is read at a reading density of 8 dots / mm, the width S2 of one pixel in the main scanning direction must be 125 μm, and the width of each of the light receiving elements 8R, 8G, 8B in the main scanning direction. 125 μm for S1
/ 3 or less. That is, the light receiving area of each of the light receiving elements 8R, 8G, 8B could not be increased, and the amount of light received by each of the light receiving elements 8R, 8G, 8B was small. For this reason, the output level of the image signal output from each of the light receiving elements 8R, 8G, and 8B decreases, and the image signal becomes susceptible to a noise component, so that the so-called S / N ratio deteriorates and the quality of the read image is improved. It becomes difficult.

[0005] The inventors of the present application have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the following technical idea. That is, as clearly shown in FIG. 7, among the three types of light receiving elements 8R, 8G, and 8B, the same type of light receiving elements are arranged in the main scanning direction, and different types of light receiving elements 8R, 8G, and 8B are used. The inventors have conceived of a configuration in which they are arranged in the sub-scanning direction. In this configuration, the light receiving elements of the same type are arranged in a row in the main scanning direction.
The width of G and 8B in the main scanning direction can be made substantially the same as the width of one pixel, and a large light receiving area in each of the light receiving elements 8R, 8G and 8B can be secured.

[0006]

However, in the above configuration, as shown in FIG. 7, the longitudinal filters 7 that transmit red, green, and blue light, respectively, are used.
R, 7G, and 7B cover the light receiving element rows arranged in the main scanning direction, so that the light receiving elements are red, green, and blue light receiving elements 8R, 8G, and 8B. There was such a problem.

That is, in the above configuration, since only the respective light receiving element rows are covered by the three types of filters 7R, 7G, 7B, the filters 7R, 7
In some cases, a part of the light emitted to a portion not covered with G and 7B enters from a portion other than the light receiving surface and reaches a pn junction in the light receiving element. That is, since the light receiving element is integrally formed on the surface of a chip-shaped substrate made of silicon or the like, light irradiated to a portion other than the light receiving surface of the light receiving element easily reaches the pn junction. I was Since the light reaching the pn junction in this manner does not pass through the filters 7R, 7G, and 7B, it also includes light other than the desired color, and the carriers generated by this light are output as noise components together with the image signal. Would. Therefore, there has been a problem that the quality of a read image is deteriorated due to mixing of noise components.

The present invention has been conceived in view of the above circumstances, and has as its object to allow each light receiving element to receive only light of a desired color that has passed through a filter.

[0009]

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

That is, according to a first aspect of the present invention, there is provided a sensor IC including a chip-shaped substrate having a rectangular shape in a plan view and a plurality of light-receiving elements for outputting a signal corresponding to the amount of received light. A plurality of light receiving elements are arranged in a row in the main scanning direction on the chip-shaped substrate, and the light receiving element rows are arranged in three rows in the sub scanning direction.
Each of the light receiving element rows is covered with three types of filters that transmit light of red, green, and blue, respectively, to form light receiving element rows for red, green, and blue, respectively. A sensor IC is provided in which a portion around the light receiving element row for each color is a light blocking portion through which light does not pass.

In the sensor IC according to the present invention, red, green, and blue light receiving elements that output signals corresponding to the amounts of received red light, green light, and blue light, respectively, are arranged in a row in the main scanning direction. The light receiving element rows are arranged in the sub-scanning direction. That is, as described above, in the sensor IC having the above-described configuration, it is possible to arrange light receiving elements having substantially the same width as the width of a pixel assigned to each light receiving element, and to secure a large light receiving area of each light receiving element. In addition, the influence of noise components is reduced
Can improve the S / N ratio of the signal output from the.

Further, in the sensor IC, since a portion around each of the light receiving element rows is a light shielding portion, only light of a desired color that has passed through each of the filters covering each light receiving element is subjected to each of the light receiving elements. The light is received by the light receiving element. In other words, the light applied to the portion around each of the light receiving element rows is absorbed by the light-shielding portion to prevent the light from reaching the chip-shaped substrate, and the light other than the desired color that does not pass through the filter is emitted. This avoids reaching the pn junction in each light receiving element. As described above, in the sensor IC, the light other than the desired color that does not pass through the filter is received by each of the light receiving elements and is prevented from being output together with the image signal as a noise component.

Normally, a wire bonding pad, such as a serial cable, is provided on the chip-shaped substrate to establish electrical continuity using wires and the like with a wiring pattern formed on a circuit board on which the sensor IC is mounted. A plurality of pads to which an IN signal is input, a pad to which a clock signal is input, and a pad to which an analog image signal is output are formed. Further, when the sensor IC is mounted on the circuit board, whether or not the sensor IC is mounted at a predetermined position is detected using, for example, an optical sensor. In such a case, On the chip-like substrate, a recognition mark used for detecting the position of the sensor IC by an optical sensor or the like is formed.
Therefore, these pad formation regions or recognition mark formation regions must not be covered by the filters.

In a preferred embodiment, the light shielding portion is formed by overlapping at least two of the three types of filters.

In the sensor IC, the light-shielding portion is formed by a filter that covers each of the light-receiving element rows. That is, in forming the light-shielding portion, the light-shielding portion can be formed by using a filter that is a light-receiving element for each color of the light-receiving element without preparing another member or the like. When at least two of the above three types of filters are overlapped, for example, when a red filter is overlaid on a blue filter,
Only the red light is transmitted by the red filter, the red light is absorbed by the blue filter, and a portion where the two types of filters, the blue filter and the red filter, are overlapped can be used as a light blocking portion without transmitting the light. of course,
Needless to say, the light-shielding portion can be formed by superposing two types of filters of different colors other than these or by superposing three types of filters.

In a preferred embodiment, each of the filters is formed of a thin film colored red, green, and blue, and each of the filters has a predetermined light receiving element to be covered by the filter. A window extending longitudinally in the main scanning direction may be formed so as not to cover the light receiving element rows other than the row.

In the above-described sensor IC, a light-shielding portion is formed by using each of the above-described filters, for example, as follows. First, each light receiving element to be a green and blue light receiving element row is provided by a red filter in which a window is formed at each part corresponding to the light receiving element row to be a green light receiving element row and a blue light receiving element row. The light receiving element row to be the light receiving element row for red is covered so that the row faces the window. Then, by a green filter having a window formed at each part corresponding to a light receiving element row to be a red light receiving element row and a blue light receiving element row, a red light receiving element row and a blue light receiving element row covered with a red filter are provided. The light receiving element array to be a green light receiving element array is covered such that the light receiving element array to be the light receiving element array faces each of the windows. Further, the blue light filters having windows formed at respective portions corresponding to the light receiving element rows to be the light receiving element rows for red and green light allow the light receiving element rows for red and blue light to pass through the window section. The light receiving element row to be the blue light receiving element row is covered so as to face each other.

That is, in the above configuration, each light receiving element row is covered with one kind of filter to form a light receiving element row for each color, and the portion around these light receiving element rows is three kinds of filters. Covered by As described above, in the present invention, the portion around each of the light receiving element rows is covered with three types of filters, as if covered by a black filter. Is a light shielding portion. Of course, the order in which the filters are superimposed is not limited to the order described above. Also, the three types of filters configured as described above are overlapped in advance,
In this state, the respective light receiving element rows may be covered.

In a preferred embodiment, each of the filters is made of a photosensitive resin colored red, green and blue, respectively.

When each of the above filters is formed of a photosensitive resin, the filters are formed through substantially the same steps as so-called photoetching. Hereinafter, the case where the red filter is formed will be briefly described. First, a photosensitive resin colored red and diluted with a solvent is uniformly applied on a chip-like substrate on which a light receiving element is formed, and then prebaked to evaporate a solvent component. Then, a portion corresponding to a portion to be a green and blue light receiving element row on the upper surface of the photosensitive resin is covered with a mask which is made not to transmit ultraviolet rays, and is irradiated with ultraviolet rays (exposure). This is processed with a predetermined processing solution (development), and a red filter is formed in a part other than a part to be a green and blue light receiving element row. Further, post-baking is performed in order to increase the degree of polymerization of the photosensitive resin and to harden it. Hereinafter, a green filter and a blue filter are formed by the same operation. Of course, the portion around each of the light receiving element rows is, for example, 3
Different types of filters are superimposed to form a black light-shielding portion.

According to a second aspect of the present invention, there is provided an image sensor comprising any one of the sensor ICs described in the first aspect.

Since the image sensor having the above configuration includes any one of the sensor ICs described in the first aspect, the effect of any one of the sensor ICs described in the first aspect is enjoyed. It goes without saying that you can do it. That is, in the above-described sensor IC, the light-receiving area of each of the light-receiving elements mounted on the chip-shaped substrate can be set to be large, and a light-shielding portion is formed in a portion around each of the light-receiving element rows, so that noise components can be reduced. It is possible to output a small image signal, that is, an image signal having a good S / N. Therefore, in the image sensor including the sensor IC, the image signal obtained by the reflected light from the original image reflects the original image well, and the quality of the read image can be improved.

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

[0024]

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 sensor IC according to the present invention, and FIG. 2 is an exploded perspective view of the sensor IC.

As shown in FIGS. 1 and 2, the sensor IC 5 includes a long rectangular chip-shaped substrate 50, a plurality of light receiving elements 1 integrally formed on the surface of the chip-shaped substrate 50, Are provided with three types of filters 7R, 7G, and 7B, each of which has light receiving elements 1 for red, green, and blue for light receiving elements 1R, 1G, and 1B.

Although not shown, a wire bonding pad, such as a serial cable, is provided on the chip-shaped substrate 50 for achieving electrical continuity using wires and the like with a wiring pattern formed on a circuit board on which the sensor IC 5 is mounted. A plurality of pads to which an IN signal is input, a pad to which a clock signal is input, and a pad to which an analog image signal is output are formed. The sensor I
When C5 is mounted on the circuit board, the sensor I
Whether or not C is placed at a predetermined position is detected using, for example, an optical sensor or the like, but the chip-shaped substrate has a recognition used for detecting the position of the sensor IC using an optical sensor or the like. A mark (not shown) is formed.

The light receiving element 1 is constituted by, for example, a phototransistor or the like, which performs a photoelectric conversion function, and outputs an analog image signal having a voltage level corresponding to the amount of received light. In addition, each of the light receiving elements 1
Are integrally formed so as to be arranged in a row in the main scanning direction of the chip-shaped substrate 50, and the light receiving element rows 10 are arranged in three rows in the sub-scanning direction.

The above three types of filters 7R, 7G, 7B
Are thin films that pass only red light, green light, and blue light of predetermined wavelengths, respectively.
R, 7G, 7B, each light receiving element row 10R, 10G,
10B, each light receiving element row 10R, 10R
G, 10B are light receiving elements NR for red, green, and blue.
NG and NB.

The red filter 7R has a light receiving element array 1 to be green and blue light receiving element arrays NG and NB.
Windows 7RG, 7RB extending longitudinally in the main scanning direction are formed at portions corresponding to 0G, 10B. Similarly, windows 7GR and 7GB are formed in the green filter 7G at positions corresponding to the light receiving element rows 10R and 10B to be the light receiving element rows NR and NB for red and blue, respectively.
The blue filter 7B includes light receiving element rows 10R and 10G to be red and green light receiving element rows NR and NG.
Windows 7BR and 7BG are respectively formed in portions corresponding to.

The three types of filters 7R, 7G, and 7B configured as described above include, for example, the red filter 7R,
Each of the light receiving element rows 10R, 10G, and 10B is superposed in the order of the green filter 7G and the blue filter 7B so that the light receiving element rows NR, NG, and N for red, green, and blue light.
B.

Specifically, first, the light receiving element rows 10G and 10B to be green and blue light receiving element rows NG and NB are respectively connected to the window portions 7RG and 7RG of the red filter 7R.
The light receiving element row 10R to be the red light receiving element row NR is covered by the red filter 7R so as to face from 7RB. The green light-receiving element array N is provided by the green filter 7G such that the light-receiving element array NR for red and the light-receiving element array 10B to be NB for blue respectively face the windows 7GR and 7GB of the green filter 7G.
The light receiving element row 10G to be G is covered. Further, the light receiving element array 10B to be the blue light receiving element array NB by the blue filter 7B such that the light receiving element arrays NR and NG for red and green respectively face the windows 7BR and 7BG of the blue filter 7B. Is covered.

Thus, each light receiving element row 10R, 1R
0G and 10B are one type of filters 7R and 7R, respectively.
G, 7B, light receiving element rows NR, N for each color
G, NB, and these light receiving element rows NR, N
The parts around G and NB are three types of filters 7R and 7R.
G, 7B. As described above, the portion around the light receiving element rows NR, NG, NB for the respective colors is covered by the three types of filters 7R, 7G, 7B, as if covered by a black filter. A portion around the light receiving element rows NR, NG, NB for the respective colors is a light shielding section 70.

As is apparent from the above description, in the sensor IC 5, the light-shielding section 70 is formed by each of the light receiving element rows N
It is formed using filters 7R, 7G, 7B covering R, NG, NB. That is, in the present invention,
In forming the light-shielding portion 70, filters 7R and 7 using the light-receiving elements 1 as light-receiving elements 1R, 1G, and 1B for each color without preparing another member or the like.
The light-shielding portion 70 can be formed using G and 7B.

As described above, the chip-shaped substrate 50
Are formed with a wire bonding pad and a recognition mark, but these formation regions must be protected from being covered by the filters 7R, 7G, and 7B. Of course, the order in which the above-mentioned 7R, 7G, 7B are superimposed is not limited to the above-described order, and the three types of filters 7R, 7G, 7B configured as described above are used.
It is needless to say that three of the light receiving element rows 10R, 10G, and 10B may be covered in advance in this state.

As described above, the sensor IC 5 has the light receiving elements 1R, 1G, 1B for red, green, and blue arranged in rows in the main scanning direction, and these light receiving element rows NR, NG. , NB are arranged in the sub-scanning direction. That is, in the sensor IC 5 having the above configuration, the light receiving elements 1R, 1G, and 1B having substantially the same width as the width of the pixel assigned to each of the light receiving elements 1R, 1G, and 1B can be arranged. By securing a large light receiving area of 1G and 1B, the so-called S / N ratio of the signal output from the sensor IC 5 can be improved.

In the sensor IC 5, a portion around each of the light receiving element rows NR, NG, NB is a light shielding portion 7.
Since it is set to 0, only light of a desired color that has passed through the filters 7R, 7G, 7B covering the light receiving elements 1 is received by the light receiving elements 1R, 1G, 1B. . In other words, each of the light receiving element rows N
Light radiated to portions around R, NG, and NB is absorbed by the light-shielding portion 50 to prevent light from reaching the chip-shaped substrate 50, and the filters 7R, 7G, and 7B
Light other than the desired color that does not pass through the light receiving elements 1R, 1R
This avoids reaching the pn junction in G, 1B. As described above, in the sensor IC 5, light other than the desired color that does not pass through the filters 7R, 7G, and 7B is received by the light receiving elements 1R, 1G, and 1B, and is output together with an image signal as a noise component. Have been avoided.

In the above-described embodiment, the light-shielding portion 70 is formed by overlapping the three types of filters 7R, 7G, and 7B. However, the three types of filters 7R, 7G,
The light-shielding portion 70 may be formed by superposing two types out of 7B. For example, when the blue filter 7B is superimposed on the red filter 7R, the blue filter 7B
Only blue light is transmitted, and this blue light is absorbed by the red filter 7R, and a portion where two types of filters, the red filter 7R and the blue filter 7B, are superposed does not transmit light and can be used as the light shielding portion 70. . Of course, it is needless to say that the light shielding portion 70 can also be formed by overlapping two types of filters of different colors other than these.

The above three types of filters 7R, 7G,
7B may be formed of a photosensitive resin colored red, green, and blue, respectively. The method of forming the three types of filters using the photosensitive resin has already been described, and thus the details are omitted here.

Next, the image sensor 1 having the sensor IC 5 will be described with reference to FIGS.

FIG. 3 is a cross-sectional view of an image sensor having the above-described sensor IC, and FIG. 4 is a plan view of a circuit board on which a plurality of the sensor ICs are mounted in a longitudinal direction. The image sensor A is configured as a so-called contact type image sensor A that can read a document image in color.

As shown in FIG. 3, the image sensor A
Are a case 2, a glass plate 3, a circuit board 4, a cold cathode tube 7,
The circuit board 4 includes a light reflection holder 75 and a lens array 9, and a control chip 6 and a plurality of sensor ICs 5 are mounted on the circuit board 4.

The case 2 is made of a synthetic resin, for example, and is formed in a relatively elongated box shape extending in a certain direction. The glass plate 3 is for placing a document (not shown) to be read facing the front surface (upper surface) of the glass plate 3 and is fitted so as to close the upper opening of the case 2. At a position facing the surface of the glass plate 3,
A platen roller that can be driven and rotated (not shown) is arranged,
The document is sandwiched between the platen roller and the surface of the glass plate 3, and is transported in the sub-scanning direction (the left-right direction in FIG. 3) by the rotation of the platen roller.

The cold cathode tube 7 serves as a white light source, and is provided in the case 2 in a shape extending in the main scanning direction of the contact type image sensor A. An electric circuit (not shown) such as an inverter circuit for driving the cold cathode tube 7 is provided in the case 2.
It is located in the right place. Further, the light source is not limited to the cold cathode tube 7, and three types of LEDs that emit red light, green light, and blue light, respectively, or a white LED may be adopted. Of course, when these LEDs are used as the light source, the configuration of the image sensor A must be appropriately changed in design.

The light reflection holder 75 is provided with the cold cathode fluorescent lamp 7.
And a portion of the white light with a high reflectivity so that white light emitted from the cold-cathode tube 7 is efficiently guided to a predetermined image reading area D on the surface of the glass plate 3. It also has a function of reflecting light in the direction of D. The light emitted from the cold-cathode tube 7 is applied to the surface of the document opposed to the surface of the glass plate 3 in the form of a band or a line extending in the main scanning direction.

The lens array 9 has a plurality of selfoc lenses 90 held in a block-shaped lens holder 91 extending in the main scanning direction. The plurality of selfoc lenses 90 are arranged in a row in the main scanning direction. It is arranged in a shape. The lens array 9 is provided between a region of the glass plate 3 to which light is irradiated and the sensor IC 5, and reflects light reflected from an original placed on the glass plate 3 to a plurality of sensor ICs 5. It plays the role of focusing on the light receiving elements 1R, 1G, 1B. In this case, the light receiving elements 1R, 1
On G and 1B, the original image is formed at the same magnification as the original.

The circuit board 4 is attached to the lower surface of the case 2 so as to close the opening of the lower surface of the case 2. As is clearly shown in FIG. 4, the circuit board 4 is provided with a connector terminal portion 40 for making electrical wiring connection with the outside of the circuit board 4. The control chip 6 and the plurality of sensor ICs 5 are connected to each other, or the control chip 6
And a wiring pattern (not shown) for conducting a plurality of sensor ICs 5 to the connector terminal portion 40.

As described with reference to FIGS. 1 and 2, the sensor IC 5 has a plurality of light receiving elements 1 integrally formed on the surface of the chip-shaped substrate 50 and a light receiving element extending in the main scanning direction. The element rows 10R, 10G, and 10B are arranged in three rows in the sub-scanning direction. Each light receiving element array 10
R, 10G and 10B have red filters 7R on the surface,
Light receiving element rows NR, NG, NB for red, green, and blue covered by green filter 7G and blue filter 7B
It has been. Each of the light receiving element rows NR, NG, NB is
For example, 96 light receiving elements 1 are integrally formed, and when reading an original image at a reading density of 8 dots / mm, each of the light receiving element rows NR, N
The pitch between the light receiving elements 1 in the longitudinal direction of G and NB is 125 μm. The image sensor A is A
In the case where a document having a width of 4 can be read at a reading density of 8 dots / mm, the light receiving element rows NR, N
Sensor I in which the number of light receiving elements 1 of G and NB is 96
A total of 18 C5s are arranged on the circuit board 4. As described above, a plurality of wire bonding pads (not shown) are formed on the chip-shaped substrate 50 of the sensor IC 5. Electrical continuity is established with the part via a wire.

Next, an example of use and operation of the image sensor A having the above configuration will be described with reference to FIG. FIGS. 5A to 5D are explanatory diagrams showing a reading operation state of a document image using the image sensor.
(E)-(h) is an explanatory view showing a state of an image signal obtained by these reading operations.

First, as shown in FIG. 5A, an original K is placed on the surface of the glass plate 3 of the image sensor A,
The surface of the document K is irradiated with white light from the cold cathode tube 7.
This white light is reflected by the surface of the document K, and then converged by the selfoc lenses 90 of the lens array 9 to the same size as the erect, and the light receiving elements 1R, 3R of the three light receiving element rows NR, NG, NB are arranged. The light is received by 1G and 1B. According to the first reading operation, FIG.
As shown in the figure, for the first line L1 of the document K, an image signal of red light is received by the light receiving element 1R, for the second line L2, an image signal of green light is received by the light receiving element 1G, and further, for the third line L3. A blue light image signal is obtained by the light receiving element 1B. In addition, FIG.
In (h), the portions indicated by black circles indicate portions where image reading has already been performed.

Next, as shown in FIG. 5B, the document K is fed further in the sub-scanning direction by a predetermined pitch, and then a second reading operation is performed. In the second reading operation, as shown in FIG. 7F, an image signal of red light is provided by the light receiving element 1R for the second line L2 of the document K, and a light receiving element 1G is provided for the third line L3. As a result, an image signal for green light is obtained, and for the fourth line L4, an image signal for blue light is obtained by the light receiving element 1B. Similarly, as shown in FIG. 3C, when the document K is further fed in the sub-scanning direction by a predetermined pitch in the sub-scanning direction, and then the third reading operation is performed, as shown in FIG. Thus, for the third line L3 of the document K, an image signal for red light is provided by the light receiving element 1R, and for the fourth line L4, an image signal for green light is provided by the light receiving element 1G.
With respect to the fifth line L5, an image signal for blue light is obtained by the light receiving element 1B.

According to the third reading operation, for the third line L3 of the document K, all the red, green, and blue light of the three color light receiving elements 1R, 1R are used.
The light is received by G and 1B, and an effective signal as an image signal of a color image is obtained. Therefore, all reading operations after the third reading operation are valid. More specifically, in the fourth reading operation shown in FIG.
Subsequently, also for the fourth line L4, all image signals of red light, green light, and blue light are obtained, and thereafter, the original K is read in the sub-scanning direction while the original K is fed in the sub-scanning direction. Then, by these reading operations, it is possible to obtain an image signal that receives all the red, green, and blue light of each reading line. The paper feed of the document K may be continuous feed instead of pitch feed.

In the image sensor A configured as described above, although a large number of light receiving elements 1R, 1G, 1B are arranged as three light receiving element rows NR, NG, NB,
The reading operation of the image of the document K can be appropriately performed.

In the image sensor A, since the light receiving element rows NR, NG, NB for the respective colors are arranged in three rows in the sub-scanning direction, the light receiving elements 1R, 1G, 1B are arranged.
The light receiving area of each of the light receiving element rows NR, NG, NB can be set large.
Is formed, it is possible to output an image signal with a small noise component, that is, a good S / N. Therefore, in the image sensor A, the image signal obtained by the reflected light from the original image reflects the original image well, and the quality of the reproduced image can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view of a sensor IC according to the present invention.

FIG. 2 is an exploded perspective view of the sensor IC.

FIG. 3 is a cross-sectional view of an image sensor including the sensor IC.

FIG. 4 is a plan view of a circuit board on which a plurality of the sensor ICs are mounted in a longitudinal direction.

FIGS. 5A to 5D are explanatory diagrams showing a reading operation state of a document image using the image sensor;
(E)-(h) is an explanatory view showing a state of an image signal obtained by these reading operations.

FIG. 6 is an explanatory diagram showing an arrangement of light receiving elements in a conventional sensor IC.

FIGS. 7A and 7B respectively show a red color, a green color,
FIG. 4 is a diagram for explaining a state in which light receiving element rows for blue are arranged in a sub-scanning direction.

[Explanation of symbols]

 Reference Signs List 1 light receiving element 1R light receiving element for red 1G light receiving element for green 1B light receiving element for blue 5 sensor IC 50 chip-shaped substrate 7R red filter 7G green filter 7B blue filter 70 light shielding part A image sensor NR red light receiving element array NG Light receiving element row for green NB Light receiving element row for blue

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

Claims (6)

[Claims] 1. A sensor IC in which a plurality of light receiving elements for outputting a signal corresponding to an amount of received light are integrally formed on a chip-shaped substrate having a rectangular shape in a plan view. The light receiving elements are arranged in a row in the main scanning direction and are built, and the light receiving element rows are arranged in three rows in the sub-scanning direction. Red, green, and blue light-receiving element rows are covered with three types of filters that transmit light of each color of red, green, and blue, respectively. A portion around the light-receiving element row for each of these colors Is a light-shielding portion through which light does not pass. 2. The sensor IC according to claim 1, wherein the light shielding portion is formed by overlapping at least two of the three types of filters. 3. The sensor IC according to claim 1, wherein each of the filters is formed of a thin film colored red, green, and blue. 4. The filter according to claim 3, wherein each of the filters has a window portion extending longitudinally in the main scanning direction so as not to cover a light receiving element row other than a predetermined light receiving element row to be covered by the filter. The sensor IC as described. 5. The sensor IC according to claim 1, wherein each of the filters is formed of a photosensitive resin colored red, green, and blue, respectively. 6. An image sensor comprising the sensor IC according to claim 1.