JPH1169082A - Sensor ic, sensor ic wafer and line image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the technology of enhancing a read image in the case of reading a color original image and to reduce the manufacture cost of the line image sensor and the sensor IC used for the line image sensor. SOLUTION: In the sensor IC 5 where a plurality of photodetectors 1 providing an output of a signal in response to a light receiving amount on chip substrates 50 formed rectangular as plane view, pluralities of the photodetectors 1 are arranged on the chip substrates 50 as columns in the main scanning direction and three photodetector arrays 10R, 10G, 10B are arranged in the subscanning direction. Each of the photodetector array 10R, 10G, 10B is respectively covered with three kinds of filters 7R, 7G, 7B that transmit through red, green and blue colors, respectively, and have a length almost corresponding to the length of light receiving element arrays 10R, 10G, 10B as red, green and blue photodetector arrays.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a line image sensor used for an image reading section or an image scanner of a facsimile apparatus, a sensor IC used for the same, and a sensor IC wafer on which a plurality of sensor ICs are formed.

[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 red light, green light, or the like.
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 line by line, it is necessary to arrange a plurality of the above three types of light receiving elements in the main scanning direction. Therefore, conventionally, as shown in FIG. 11, each of the red light receiving element 8R, the green light receiving element 8G, and the blue light receiving element 8B is repeatedly arranged in a certain order. Are arranged in a line in the main scanning direction. In such a configuration, a total of three light receiving elements 8R, 8G, and 8B for each color light constitute one set, and this set is responsible for reading an image of one pixel.

The light receiving elements 8R, 8G, 8B for each of the above color lights
The light receiving elements integrated on the surface of a chip-shaped substrate made of silicon etc. are separated by a red filter that transmits red light, a green filter that transmits green light, and a blue filter that transmits blue light. The cover is configured to receive light of the color assigned to each of them by covering.

[0005]

However, in the above configuration, since a total of three light receiving elements 8R, 8G, and 8B are responsible for reading one pixel of an image, the original image is read at the same magnification. In this case, each of the light receiving elements 8R, 8
The width S1 of G, 8B in the main scanning direction must be equal to or less than 1/3 of the width S2 of one pixel in the main scanning direction. For example, when a read original is read at a reading density of 8 dots / mm, the width S1 of one pixel in the main scanning direction is 125.
μm, and the width S2 of each light receiving element in the main scanning direction must be set to 125/3 μm or less. That is, the light receiving area of each of the light receiving elements 8R, 8G, 8B cannot be increased, and
The amount of light received at R, 8G, and 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.

The width S of each light receiving element in the main scanning direction is
As described above, 2 must be 125/3 μm or less, and the filter covering each light receiving element is also
Correspondingly, the width must be less than 125/3 μm. Since the light receiving elements are arranged in a row in the main scanning direction close to each other, it is difficult to cover the light receiving elements with such an extremely narrow filter. Moreover, it is more difficult to select a desired light receiving element from a light receiving element group arranged close to each other and cover it with a desired filter. Therefore, in order to surely perform such an operation, it is necessary to tolerate a decrease in the yield, and also to tolerate a cost increase.

Further, in the sensor IC employed in the image reading apparatus, each of the light receiving elements is covered by a filter piece having a width of 125/3 μm or less. When an external force, heat, or the like is applied, there is a risk that the filter piece may be separated from the light receiving element.

The present invention was conceived under the circumstances described above, and provides a technique for improving the quality of a read image when reading an original image in color.
Line image sensor and sensor I used therefor
The object is to reduce the manufacturing cost of C.

[0009]

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

That is, according to the first aspect of the present invention, a sensor in which a plurality of light receiving elements for outputting a signal corresponding to the amount of received light are integrally formed on a chip-shaped substrate having a rectangular shape in plan view. An IC wherein a plurality of light receiving elements are built on the chip-shaped substrate so as to be arranged in a row in the main scanning direction, and the light receiving element rows are arranged in three rows in the sub scanning direction. And each of the light receiving element rows transmits light of each color of red, green, and blue, and is formed into three types of strips having a length substantially corresponding to the length of each light receiving element row. A sensor IC is provided, which is covered with a filter and includes light receiving element arrays for red, green, and blue, respectively.

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, in the sensor IC having the above configuration, it is possible to arrange light receiving elements having substantially the same width as the pixel that each light receiving element is in charge of, and to secure a large light receiving area for each light receiving element. The amount of light received can be improved. Thereby, the output level of the image signal output from each of the light receiving elements is improved, the influence of the noise component is reduced, the S / N ratio of the signal output from the sensor IC is improved, and the quality of the read image is improved. Can be increased.

Further, in the above configuration, each of the light receiving element rows is covered by one band-shaped filter having a length corresponding to the length of each light receiving element row.
Unlike the conventional case, it is not necessary to cover each light receiving element with a filter of a size corresponding to the light receiving element. In other words, it is sufficient to cover each light receiving element row with a filter for a desired color, and a single sensor IC may be covered with a total of three filters. Therefore, it is not necessary to select and cover a desired number of light-receiving elements from a group of light-receiving elements arranged very close to three times the number of pixels handled by the sensor IC as in a conventional sensor IC. And productivity can be remarkably improved.

Further, in the above configuration, since each light receiving element row is covered by the filter, compared with the case where each light receiving element is covered by the filter made into fine pieces, it is less affected by external force and heat. Strongly, the risk that the filter covering the light receiving element is peeled off is reduced.

In a preferred embodiment, each of the filters has a width in the sub-scanning direction set to be larger than a width in the sub-scanning direction of each of the light receiving element rows. It covers so that it overlaps.

Since the chip-like substrate is formed of, for example, silicon, even if light incident from a portion other than the light-receiving surface, a part of the light enters the p-type of the light-receiving element.
In some cases, the noise reaches the n-junction and is output as a noise component. In the above configuration, since the light receiving surface of each of the light receiving elements is completely covered by the filter, and the area around the light receiving surface is also covered by the filter, the light is incident around the light receiving surface of the chip-shaped substrate. The transmitted light reaches the pn junction of the light receiving element after passing through the filter. That is, in the above sensor IC,
Even the light irradiated around the light receiving surface is the same as that received by the light receiving element after passing through the filter, and can be output as a read image signal instead of a noise component.

In a preferred embodiment, each of the filters is made of a photosensitive resin colored red, green, and blue, respectively, and each of the filters is colored red, green, and blue, respectively. It may be formed by a thin film formed.

When each of the filters is made of a photosensitive resin, it can be formed, for example, through substantially the same steps as so-called photoetching. The details of the step of forming the filter with the photosensitive resin will be described later, and thus are omitted here.

According to a second aspect of the present invention, there is provided a sensor IC wafer having at least a plurality of the sensor ICs described in the first aspect described above formed at least in the main scanning direction. A dicing line that is cut to obtain a single sensor IC is set between adjacent sensor ICs, and each light receiving element row is covered by each filter for each sensor IC. A sensor IC wafer is provided which is divided at a line portion.

In a preferred embodiment, the width in the main scanning direction of the area where each of the filters is divided is set to be larger than the width of the dicing line in the main scanning direction.

The sensor IC wafer is cut into a single sensor IC by cutting adjacent portions between the sensor ICs. This cutting operation is performed using a diamond blade or a laser. For this reason, when the light receiving element row of each sensor IC is covered by each of the above filters, and the sensor ICs adjacent in the main scanning direction are also covered by a continuous filter and cut off, the sensor ICs of the sensor ICs are cut off. The end of the filter faces the end. For this reason, the end of the filter is likely to peel off under the influence of external force or the like, and the end of the filter may be peeled off together when cutting with, for example, a diamond blade. I am concerned.

In the sensor IC wafer having the above configuration, the width in the main scanning direction of the area where each of the filters is divided is set to be larger than the width of the dicing line in the main scanning direction, that is, the blade width. The end of the filter of a single sensor IC, which is obtained by cutting the sensor IC wafer, is located at a position slightly shifted inward from the end of the sensor IC. For this reason, in the sensor IC obtained in this way, since the end of the filter does not face the end of the sensor IC, it is possible to avoid a situation in which the end of the filter is peeled off due to an external force or the like. ing. Further, since the filter itself is not cut, the end of the filter is not peeled off at the time of cutting.

According to a third aspect of the present invention, a circuit board, a sensor IC mounted on the circuit board, and a light converging device for converging light reflected from a read original emitted from a light source onto the sensor IC. And a member, wherein the sensor IC is any one of the sensor ICs described in the first aspect or the sensor is any one of the sensors described in the second aspect. I
A line image sensor is provided, wherein a sensor IC obtained from a C wafer is used, and a plurality of sensor ICs are arranged in a row in the main scanning direction of the circuit board.

In a preferred embodiment, the light converging member is configured to form an image of reflected light from the original on the sensor IC at an equal size of an erect image.

In the above line image sensor, the sensor I
Since any one of the sensor ICs described in the first aspect described above or any one of the sensor IC wafers described in the second aspect described above is used as C, Any of the effects described in the first aspect and the second aspect can be enjoyed. That is, the sensor IC described in the first aspect is
Compared to conventional sensor ICs, it can be manufactured at a higher yield, at lower cost, and can improve the quality of a read image. Therefore, in a line image sensor using this,
The manufacturing cost can be reduced, and a high quality read image can be obtained. Further, in the line image sensor using the sensor IC described in the second aspect, it is possible to enjoy the effect that the end portion of the filter covering the light receiving element row is hardly peeled off.

[0025] Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

[0026]

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. As is clearly shown in FIG. 1, the sensor IC 5 includes a long rectangular chip-shaped substrate 50 and a surface of the chip-shaped substrate 50. And a plurality of light receiving elements 1 integrally formed with the light receiving elements 1 and light receiving elements 1R, 1G, and 1B for red light, green light, and blue light.
The filters 7R, 7G, and 7 are provided.

Although not shown, the chip-shaped substrate 50 has a wire bonding pad, such as a serial cable, for establishing 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 C5 is placed at a predetermined position is detected using, for example, an optical sensor or the like.
At 0, a recognition mark (not shown) used for detecting the position of the sensor IC 5 by the optical sensor is formed.

The light receiving element 1 is constituted by, for example, a phototransistor which exhibits 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 are arranged in three rows in the sub-scanning direction.

The above three types of filters 7R, 7G, 7B
Are made of, for example, a photosensitive resin colored red, green, and blue, respectively, which allows only red light, green light, and blue light of predetermined wavelengths to pass therethrough. Also,
Each of the filters 7R, 7G, and 7B is formed in a band shape having a length substantially corresponding to the length of each of the light receiving element rows 10R, 10G, and 10B in the main scanning direction. 7B is set to be larger than the width of each of the light receiving elements 1 in the sub-scanning direction. Each of the light receiving element rows 10R, 10G, 10B is covered with these band-shaped filters 7R, 7G, 7B, and the light receiving elements NR, NG, NG for red, green, and blue, respectively.
NB.

As described above, the sensor IC 5 having the above configuration is
Red, green, and blue light receiving elements 1R, 1 that output signals corresponding to the amounts of received red light, green light, and blue light, respectively.
G and 1B are arranged in a row in the main scanning direction, and the light receiving element rows NR, NG, and NB are arranged in three rows in the sub-scanning direction. That is, in the sensor IC 5 having the above-described configuration, it is possible to arrange the light receiving elements 1 having substantially the same width as the pixels assigned to the respective light receiving elements 1, and to secure a large light receiving area of each light receiving element 1. The amount of light received by the light receiving element 1 can be improved.
As a result, the output level of the image signal output from each of the light receiving elements 1 is improved, the influence of noise components is reduced, and the S / S of the signal output from the sensor IC 5 is reduced.
By improving the N ratio, the quality of the read image can be improved.

In the above configuration, each of the light receiving element rows N
R, NG, and NB are light receiving element rows NR, NG,
Since it is covered by one band-shaped filter 7R, 7G, 7B having a length corresponding to the length of NB,
It is not necessary to cover each light receiving element 1 with a filter of a size corresponding to this, as in the related art. That is, the band filters 7R, 7R for the desired color are provided for each light receiving element row NR, NG, NB.
G and 7B, and three sensors 7R, 7G and 7B in total for one sensor IC 5. Therefore, like a conventional sensor IC, the work of selecting and covering a desired light receiving element 1 from a group of light receiving elements 1 arranged very close to three times the number of pixels handled by this sensor IC is not required. There is no need, and productivity can be significantly improved.

Further, in the above configuration, each light receiving element row N
Since each of R, NG, and NB is covered by the filters 7R, 7G, and 7B, compared to the case where each light receiving element 1 is covered by a filter made of fine pieces, the light receiving element 1 is more resistant to external force, heat, and the like. The risk that the filters 7R, 7G, 7B covering the light receiving element 1 are peeled off is reduced.

Conventionally, the chip-shaped substrate 50
Is formed of, for example, silicon or the like, so that even if the light is incident from a portion other than the light receiving surface, part of the light reaches the pn junction of the light receiving element and is output as a noise component. was there. In the sensor IC 5, the light receiving surface of each light receiving element 1 is completely covered by each of the filters 7R, 7G, and 7B, and the area around the light receiving surface is also covered by each of the filters 7R, 7R.
Since it is covered by 7G and 7B, the light incident around the light receiving surface reaches the pn junction of the light receiving element after passing through the filters 7R, 7G and 7B. That is, in the sensor IC5, even if the light is irradiated around the light receiving surface, the filters 7R, 7G, 7
This is the same as that received by the light receiving element 1 after passing through B, and can be output not as a noise component but as a read image signal.

In the above embodiment, each of the filters 7R, 7G, 7B is formed of a photosensitive resin. However, the present invention is not limited to this. Each of the filters 7R, 7G, 7B may be formed of a thin film colored in a predetermined color. It may be.

FIG. 2 is a plan view of a principal part of the sensor IC wafer according to the present invention, and FIG. 3 is an enlarged view of a region surrounded by a chain line C in FIG.

The sensor IC wafer 20 is formed in a notched disk shape by, for example, silicon or the like, and a plurality of sensor ICs 5 are formed vertically and horizontally. That is, FIG.
And as best seen in FIG. 2, individual sensor ICs
The light receiving elements 1 are integrally formed in three rows in each of the regions to be 5, and each of the light receiving elements 1 is, for example, a photosensitive resin or a thin film colored in a predetermined color. Light receiving elements 1R, 1G,
1B. The sensor IC wafer 20 has an adjacent portion between the sensor ICs 5 (a portion indicated by a two-dot chain line in FIG. 1,
The individual sensor ICs 5 are cut off at dicing lines 21 set in the shaded portions in FIG. 2) as shown in FIG.

This cutting operation is performed using, for example, a diamond blade or a laser. Therefore, each sensor I
When the light receiving element rows NR, NG, and NB of C5 are covered and the sensor ICs 5 and 5 adjacent in the main scanning direction are covered by the continuous filters 7R, 7G, and 7B and cut off, The ends of the filters NR, NG, and NB face the ends of the sensor IC5. Therefore, the filters NR, NG, N
There is a concern that the ends of B will be easily peeled off, and that the ends of the filters NR, NG, NB will be peeled off together when cutting with, for example, a diamond blade.

As is clearly shown in FIG. 2, the sensor IC wafer 20 has the sensor ICs adjacent to each other in the main scanning direction.
The filters 7R, 7G, and 7B are formed in the same straight line, respectively. However, in the portion where the dicing line 21 is set, the filters 7R, 7G, and 7B are formed.
Is divided. In addition, each of the filters 7R, 7R
The width of the area where G and 7B are separated in the main scanning direction is set to be larger than the width of the dicing line 21.

That is, the sensor IC wafer 2 having the above configuration
0, the width in the main scanning direction of the area where each of the filters 7R, 7G, and 7B is divided is set to be larger than the width of the dicing line 21 in the main scanning direction, that is, the blade width. Filters 7R, 7G, 7B of sensor IC5 obtained by cutting wafer 20
The end of the sensor I, as best seen in FIG.
It will be located at a site that has shifted slightly inward from the end of C5. For this reason, the sensor IC thus obtained
5, the ends of the filters 7R, 7G, 7B are sensor ICs.
Since the end portions of the filters 5R, 7G, and 7B are not affected by external force and the like, the end portions of the filters 7R, 7G, and 7B are prevented from coming off. Also, the filter 7R,
Since the 7G and 7B are not cut, the ends of the filters 7R, 7G and 7B are not peeled off at the time of cutting.

The above filters 7R, 7G, 7B
Is formed of a photosensitive resin or a thin film as described above. Hereinafter, the case where the filters 7R, 7G, and 7B are formed of the photosensitive resin will be described with reference to FIGS. This will be briefly described with reference to FIG.

FIG. 4 is a view for explaining a step of covering a light receiving element integrally formed with each sensor IC of the sensor IC wafer with a red filter, and FIG. 5 is a view showing a state of FIG. 3 (b). FIG. 2 is a plan view showing a region corresponding to a region surrounded by a dashed line C in FIG. 1. FIG. 6 is a view for explaining a step of covering a light receiving element integrally formed with each sensor IC of the sensor IC wafer with a green filter.
FIG. 4 is a view for explaining a step of covering a light receiving element integrally formed with each sensor IC of the sensor IC wafer with a blue filter. In the present embodiment, red,
The case where the filters 7R, 7G, and 7B are formed in the order of green and blue will be described.

First, a sensor IC wafer 20 which is formed in a notched disk shape by, for example, silicon and has a plurality of sensor ICs 5 vertically and horizontally formed with a light receiving element, a wiring pattern and the like formed at a predetermined portion. After the cleaning, as shown in FIG. 4A, a red colored photosensitive resin is uniformly applied to one surface of the sensor IC wafer 20 to form a red coating film 70R. This step is performed by, for example, a so-called spinning method using a red coating solution obtained by diluting polyvinyl cinnamate to a predetermined viscosity with an organic solvent or the like, and mixing a substance to be a red component.

Subsequently, as described above, the red coating film 70R
Is prebaked on the sensor IC wafer 20 on which is formed. That is, the sensor IC wafer 20 is
After drying at about 0 ° C., the remaining solvent component is evaporated to increase the hardness of the red coating film 70R.

Next, as shown in FIG. 4B, a mask 71R having a predetermined portion as a window 74R through which ultraviolet light is transmitted is brought into close contact with the red coating film 70R.
By irradiating ultraviolet rays having a wavelength of about 365 nm from above 1R, the red coating film 70R at the portion corresponding to the window 74R is polymerized and cured (exposure). As shown in FIGS. 4B and 5, the mask 71R is formed by forming a light-shielding film 73 on a glass plate 72 with a metal or the like, and the mask 71R is brought into close contact with the red coating film 70R. In this state, the pattern is formed such that the portion to be the red light receiving element row NR faces the window 74R. And as best seen in FIG.
In the mask 71R, a light-shielding film 73 is formed in a portion corresponding to the area between the sensor ICs 5 and 5 adjacent to each other in the main scanning direction formed on the sensor IC wafer 20, and the red filter is formed on the sensor IC wafer 20. When the 7R is formed, the red filter 7R is separated from each other between the sensor ICs 5 adjacent in the main scanning direction.

Subsequently, after the mask 71R is removed, a portion of the red coating film 70R that has not been irradiated with ultraviolet rays is dissolved using a predetermined processing solution (development).
Furthermore, after removing the dissolved unnecessary portion by rinsing, by performing a so-called post-bake to evaporate the organic solvent contained in the processing solution and increase the hardness,
As shown in FIG. 4C, a red filter 7R is formed at a portion to be the light receiving element row NR for red. Needless to say, the red filter 7R is divided at a portion between the adjacent sensor ICs 5.

Hereinafter, the green filter 7 goes through substantially the same steps.
The G and blue filters 7B are formed. That is, first, as shown in FIG.
After the cleaning of the sensor I by the spinning method,
A green coating film 70G is formed on the C wafer 20. Of course, the green coating film 70G is also formed on the red filter 7R.
Is formed. Next, as shown in FIG. 6B, after the sensor IC wafer 20 is pre-baked, an exposure process is performed using a mask 71G having a window 74G formed in a portion to become the green light receiving element row NG. Further, by performing a developing process, a rinsing process, and a post-bake, FIG.
A green filter 7G is formed as shown in FIG. As shown in FIG. 7A, after successive cleaning, a blue coating film 70B is formed on the sensor IC wafer 20 by a spinning method, and exposure is performed using a mask 71B as shown in FIG. 7B. By performing the processing, and further performing the developing processing, the rinsing processing, and the post-baking, a blue filter 7G as shown in FIG. 7C is formed.

As described above, the sensor IC wafer 2
At 0, a red filter 7R, a green filter 7R, and a blue filter 7R are respectively formed, and the respective light receiving element rows 10R, 10G, and 10B of the sensor ICs 5 are provided with a red light receiving element row NR and a green light receiving element row, respectively. NG, blue light receiving element array NB. In the above-described exposure process, the light shielding film 7 is formed on a portion corresponding to the area between the sensor ICs 5 and 5 adjacent to each other in the main scanning direction formed on the sensor IC wafer 20.
Since the masks 71R, 71G, and 71B on which the first and second filters 3R, 7G, and 7B are formed are used between the sensor ICs 5 adjacent in the main scanning direction, as shown in FIG. Is in a state of being divided.

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

FIG. 8 is a cross-sectional view of a line image sensor provided with the sensor IC having the above configuration, and FIG. 9 is a plan view of a circuit board on which a plurality of the sensor ICs are mounted in the longitudinal direction. The line image sensor A is configured as a so-called contact type line image sensor A that can read a document image in color.

As shown in FIG. 8, the line image sensor A includes a case 2, a glass plate 3, a circuit board 4, a cold cathode tube 7, a light reflection holder 75, and a lens array 9. The circuit board 4 includes a control chip 6
And a plurality of sensor ICs 5 are mounted.

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. 8) 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 so as to extend in the main scanning direction of the contact type line image sensor A. An electric circuit (not shown) such as an inverter circuit for driving the cold-cathode tube 7 is provided at an appropriate place in the case 2. Further, the light source is not limited to the cold-cathode tube 7, but three types of LEDs emitting red light, green light, and blue light, respectively, or a white LED.
May be adopted. Of course, these LEs as light sources
When D is adopted, the configuration of the line image sensor A must be appropriately changed in design.

The light reflecting 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 shown in FIG. 9, 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 FIG. 1, the sensor IC 5 has a plurality of light receiving elements 1 integrally formed on the upper surface of the chip-shaped substrate 50, and a light receiving element row 10R extending in the main scanning direction. , 10G, and 10B are arranged in three rows in the sub-scanning direction. Each of the light receiving element rows 10R, 10G, 1
0B indicates that the surface has a red filter 7R and a green filter 7R.
G, covered by a blue filter 7B, are light receiving element arrays NR, NG, NB for red, green, and blue. Each of the light receiving element rows NR, NG, NB is, for example, 9
When the original image is read at a reading density of 8 dots / mm, the light receiving elements 1 in the longitudinal direction of the light receiving element rows NR, NG, NB are read. The pitch between them is 125 μm. When the line image sensor A is configured to be able to read an A4 width document at a reading density of 8 dots / mm, the number of the light receiving elements 1 in each of the light receiving element rows NR, NG, NB is 96. The sensor ICs 5 are arranged on the circuit board 4 in a total of 18 rows. In addition,
As described above, the chip-shaped substrate 50 of the sensor IC 5
Are formed with a plurality of wire bonding pads (not shown), and these pads are electrically connected to predetermined portions of the wiring pattern formed on the circuit board 4 via wires. .

Next, the line image sensor A having the above configuration
The use example and the operation of will be described with reference to FIG. FIGS. 10A to 10D are explanatory diagrams showing the operation of reading an original image using the line image sensor, and FIGS. 10E to 10H show images obtained by the reading operation. FIG. 4 is an explanatory diagram showing states of signals.

First, as shown in FIG. 10A, an original K is arranged on the surface of the glass plate 3 of the line image sensor A, and white light is emitted from the cold cathode tube 7 to the surface of the original K. . This white light is reflected by the surface of the document K and then converged by the respective SELFOC lenses 90 of the lens array 9 to the same size as the erect, and the three light receiving element arrays NR and N
The light is received by the respective light receiving elements 1R, 1G, 1B of G and NB. According to this first reading operation,
As shown in FIG. 3E, the first line L1 of the original K
With respect to the image signal of red light by the light receiving element 1R,
For the second line L2, an image signal of green light is obtained by the light receiving element 1G, and for the third line L3, an image signal of blue light is obtained by the light receiving element 1B. In addition,
In (e) to (h), the portions indicated by black circles indicate portions where image reading has already been performed.

Next, as shown in FIG. 6B, the document K is further fed by a predetermined pitch in the sub-scanning direction, 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 original K, all three color light components of red light, green light and blue light are subjected to three types of light receiving elements 1R and 1R.
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 line image sensor A configured as described above, the image of the original K is obtained despite the fact that a large number of light receiving elements 1R, 1G, 1B are arranged as three light receiving element rows NR, NG, NB. Can be performed appropriately.

In the line 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, 1
The light receiving area of G, 1B can be set large, and the light shielding portion 70 is formed around the light receiving element rows NR, NG, NB, so that the noise component is small, that is, S / N. Can be output. Therefore, in the line image sensor A, the image signal obtained by the reflected light from the original image becomes a good reflection of the original image, 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 a plan view of a main part of a sensor IC wafer according to the present invention.

FIG. 3 is an enlarged view of a region surrounded by a dashed line C in FIG. 2;

FIG. 4 is a view for explaining a step of covering a light receiving element integrally formed in each sensor IC of the sensor IC wafer with a red filter.

FIG. 5 is a plan view illustrating the state of FIG. 3B with respect to a region corresponding to a region surrounded by a dashed line C in FIG. 2;

FIG. 6 is a view for explaining a step of covering a light receiving element integrally formed in each sensor IC of the sensor IC wafer with a green filter.

FIG. 7 is a view for explaining a step of covering a light receiving element integrally formed in each sensor IC of the sensor IC wafer with a blue filter.

FIG. 8 is a cross-sectional view of a line image sensor including the sensor IC.

FIG. 9 is a plan view of a circuit board on which a plurality of the sensor ICs are mounted in a longitudinal direction.

FIGS. 10A to 10D are explanatory diagrams showing a reading operation state of a document image using the line image sensor, and FIGS. 10E to 10H are images obtained by the reading operation; FIG. 4 is an explanatory diagram showing states of signals.

FIG. 11 is an explanatory diagram showing an arrangement of light receiving elements in a conventional sensor IC.

[Explanation of symbols]

 Reference Signs List 1 light receiving element 1R light receiving element for red light 1G light receiving element for green light 1B light receiving element for blue light 4 circuit board 5 sensor IC 7 cold cathode tube (as light source) 7R red filter 7G green filter 7B blue filter 9 lens Array (as a light focusing member) 20 Sensor IC wafer 21 Dicing line 50 Chip-shaped substrate 70 Shielding section A Line image sensor NR Light receiving element array for red light NG Light receiving element array for green light NB Light receiving element array for blue light

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

Claims (8)

[Claims] 1. A chip-like substrate having a rectangular shape in a plan view,
A sensor IC in which a plurality of light receiving elements for outputting a signal corresponding to the amount of received light are integrally formed, wherein the plurality of light receiving elements are formed on the chip-shaped substrate so as to be arranged in a row in the main scanning direction. And the light receiving element rows are arranged in three rows in the sub-scanning direction. Each of the light receiving element rows transmits light of each color of red, green, and blue, and It is covered with three types of filters formed in a strip shape having a length substantially corresponding to the length of the light receiving element row, and is used as a red, green, and blue light receiving element row, respectively. Sensor IC. 2. Each of the filters has a width in the sub-scanning direction set to be larger than a width in the sub-scanning direction of each of the light receiving elements, and each of the filters overlaps each of the light receiving elements. The sensor IC according to claim 1, wherein the sensor IC covers. 3. The sensor IC according to claim 1, wherein each of the filters is formed of a photosensitive resin colored red, green, and blue, respectively. 4. The sensor IC according to claim 1, wherein each of the filters is formed of a thin film colored red, green, and blue. 5. A sensor IC wafer having at least a plurality of sensor ICs according to claim 1 formed in a main scanning direction, wherein a sensor IC is provided between adjacent sensor ICs in the main scanning direction. A dicing line that is cut to obtain a single product is set, and each of the light receiving element rows is covered with each of the filters for each of the sensor ICs, and each of the filters is divided at a portion of the dicing line. A sensor IC wafer, characterized in that: 6. The sensor IC wafer according to claim 5, wherein the width in the main scanning direction of the area where each of the filters is divided is set to be larger than the width of the dicing line in the main scanning direction. 7. A line image sensor comprising: a circuit board; a sensor IC mounted on the circuit board; and a light converging member for converging light emitted from a light source and reflected on a read original onto the sensor IC. A sensor IC according to any one of claims 1 to 4, or a sensor IC obtained from a sensor IC wafer according to claim 5 or 6, is used as the sensor IC. Wherein the sensor ICs are arranged in a row in the main scanning direction of the circuit board. 8. The line image sensor according to claim 7, wherein the light converging member is configured to form an image of reflected light from the document on the sensor IC at an erect equal size.