JP2000324298A - Color line image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To acquire the RGB colors via a single reading operation using an almost white light source and to increase the reading speed of an original by means of a monochromatic photosensor chip by forming the RGB color filters at the positions, where the beams forming an image on the photosensor chip do not mutually interfere. SOLUTION: A lens array 3 prescribes the reading surface of an original put on a transparent panel via this panel, the original is irradiated with the light of an almost white light source and forms a correct reading image of the original on the path of the light reflected on the transparent panel. Monochromatic photosensor chips 7a to 7c are placed on a transparent circuit board 4 to apply the photoelectric transformed to the image information that is formed into an image on the array 3 via a transparent conductive material 11. The three RGB color filters 10a to 10c are formed on the opposite surface of the substrate 4, which correspond to the chips 7a to 7c respectively. With such a constitution, a small and fast color image sensor which is hardly affected by resolution, aberration, etc., can be obtained by means of a lens of a single system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color line image sensor used for facsimile machines, copiers, scanners, and the like, and more particularly to a color line image sensor requiring space saving, such as a portable or home use. Things.

[0002]

2. Description of the Related Art A conventional monochromatic line image sensor is mainly of a reduced optical type using a CCD type photo sensor chip. However, due to the fact that it takes time to adjust the optical axis during assembly and is not suitable for saving space, there is a growing demand for a contact type line image sensor using a MOS photosensor chip, and the usage applications are expanding rapidly. It is getting.

On the other hand, a color line image sensor needs to separate information of one pixel of a document into three colors of R (red), G (green), and B (blue) and read the information as information for each color component. Therefore, a photo sensor three times as large as the monochrome type is required.

Here, the CCD-type photosensor chip can easily form a large number of photosensors in a narrow area because it is easy to make the photosensors narrower in pitch and smaller in size. Has been used as an area sensor for cameras. Also, with the improvement of the color filtering technology, it is possible to form R, G, and B filters in accordance with the size of the light receiving window of the photosensor.

Therefore, by combining these techniques, a total of R rows provided with R filters, G rows provided with G filters, and B rows provided with B filters are provided for one original reading line. A CCD type color photosensor chip in which three rows of photosensors are formed at a narrow pitch is manufactured.

If this chip is used, a CCD reduced optical type color line image sensor can be manufactured in almost the same manner as in monochrome, while maintaining the optical system (light source, reduction lens, mirror) as one system. At present, the image sensor occupies the majority in the field of color.

On the other hand, in the case of the MOS type photo sensor chip, it is difficult to narrow the pitch of the photo sensor because the output transmission system of the photo sensor is different from that of the CCD type.
Chips with rows of photosensors are not currently available on the market. Here, as a color line image sensor using a MOS type chip for monochrome, a method in which three light sources of RGB are prepared and one original is sequentially illuminated with light sources of each color and read, that is, a light source switching method is considered. ing.

[0008]

In the case of a CCD type reduction optical type color line image sensor, it takes time to adjust the optical axis at the time of assembly as in the case of monochrome.
There is a problem that it is not suitable for saving space.

On the other hand, in the case of a MOS-type contact type color line image sensor, a method using a MOS-type chip in which three rows of RGB photosensors are arranged in one chip has not been found in the market as described above. Since there is no such record, there are many unknowns in terms of chip yield, quality, reliability, and cost.

Further, the light source switching method using the RGB light sources has the advantage that the monochrome sensor chip can be used as it is, the lens can be one system, and the external dimensions can be reduced to almost the same size as the conventional monochrome line image sensor. However, since it is necessary to read one original with light sources of the respective colors, the reading speed is three times or more as compared with the related art, and there is a problem that the usability is extremely deteriorated.

Further, RG is used for the monochrome sensor chip.
It is conceivable that a three-line color line image sensor is configured by disposing each filter of B and mounting these chips on a substrate as close as possible.

However, since the sensor chip and the substrate are generally electrically contacted by wire bonding, the gap between adjacent sensor chip rows must be at least 1.5 mm. Then, since a single lens system deteriorates characteristics such as resolution and aberration, a plurality of lenses are required. For this reason, the external dimensions of the product become large, and the accuracy of optical axis adjustment becomes strict.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color line image sensor using a monochrome photosensor chip without lowering the reading speed.

[0014]

In order to solve this problem, a color line image sensor according to the present invention comprises a transparent plate defining a reading surface of an original, and a reading surface of the original placed on the transparent plate. A light source for irradiation, a lens array arranged on a path of light reflected from the transparent plate, and erectly forming an image of a read document, and a lens array mounted on a transparent circuit board via a transparent conductor and connected to the lens array. A plurality of monochrome photosensor chips that read photoelectrically converted image information, and a plurality of photosensor chips on a transparent circuit board on a light path from the lens array to the photosensor chip on a surface opposite to a mounting surface of the photosensor chip. The configuration has three color filters of red, green, and blue formed corresponding to the photosensor chips, respectively.

Thus, it is possible to increase the reading speed of the original while using the photosensor chip for monochrome.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to a first aspect of the present invention is directed to a transparent plate for defining a reading surface of a document, a light source for illuminating the reading surface of the document placed on the transparent plate, and a transparent plate. A lens array that is arranged on the path of reflected light from the camera and erectly forms an image of a read document, and is mounted on a transparent circuit board via a transparent conductor, and photoelectrically converts image information formed on the lens array. A plurality of monochrome photosensor chips, and a plurality of photosensor chips on the light path from the lens array to the photosensor chip on the surface opposite to the mounting surface of the photosensor chip on the transparent circuit board. Red, green and blue 3
This is a color line image sensor having a color filter for colors, and has an effect that the original reading speed can be increased while using a photosensor chip for monochrome.

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG. In these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

FIG. 1 is a sectional view showing a color line image sensor according to an embodiment of the present invention, and FIG. 2 is an enlarged sectional view showing a main part of the color line image sensor of FIG.

As shown in FIGS. 1 and 2, the color line image sensor of the present embodiment is formed of, for example, glass on one side of a frame 9 made of, for example, aluminum or the like. A transparent plate 2 for defining a reading surface is provided. Further, inside the transparent plate 2, a light source 1 made of, for example, a cold cathode tube of substantially white light and irradiating a document placed on the transparent plate 2 is attached.

On the path of the reflected light of the light emitted from the light source 1 to the original on the transparent plate 2, a lens array 3 for erectly forming an image read from the original and an image formed on the lens array 3 Monochrome photosensor chips 7a to 7c for reading information by photoelectrically converting the information are arranged. On the other side of the frame 9, such a photo sensor chip 7a
A transparent circuit board 4 made of glass or the like, which is mounted with, for example, flip chips, is mounted. Circuit components 6 for driving the photosensor chips 7 a to 7 c are provided on the transparent circuit board 4 via the flexible circuit board 5.

The photosensor chips 7a to 7c are sealed with a black potting resin 8 such as silicon.

On the surface of the transparent circuit board 4 opposite to the surface on which the photosensor chips 7a to 7c are mounted, red (R),
Green (G) and blue (B) color filters 10a to 10c
From the lens array 3 to the photosensor chips 7a to 7c
Are formed on the path of the light traveling toward (the broken line in FIG. 2). The mounting surface of the photosensor chips 7a to 7c on the transparent circuit board 4, for example, ITO (In)
-Sn-Oxides) or the like,
A predetermined circuit pattern is formed facing the color filters 10a to 10c by the green film 12 and the metal film 13 such as silica. The circuit pattern is formed using a film forming technique such as sputtering.

Here, the metal film 13 having such a circuit pattern is electrically connected to the electrode pads 14a to 14c of aluminum or the like by using a gold bump bonding technique. The sensor chips 7a to 7c are electrically connected. The photo sensor chips 7a to 7c have photo sensor arrays 15a to 15c for photoelectrically converting image information.

Here, the photo sensor chips 7a to 7c
Are mounted on the transparent circuit board 4 substantially linearly in the main scanning direction in a required number according to the reading width of the document.

A land 16 electrically connected to the metal film 13 is provided at a predetermined position on the flexible circuit board 5, and the flexible circuit board 5 on which the circuit components 6 are mounted and the transparent circuit board 4 are connected. The electrical contact is made between the land 16 and the metal film 13 by an anisotropic conductive sheet, solder, conductive resin, gold bump, solder bump, or the like.

Next, the operation of the color line image sensor having such a configuration will be described.

The substantially white light emitted from the light source 1 passes through the transparent plate 2 and reaches the surface of the document to be read whose position is defined by the transparent plate 2. Then, reflected light is generated from the document surface with image information of the document.

A part of the reflected light passes through the lens array 3 to form an erect image on the surface including the photosensor arrays 15a to 15c. Then, the imaged information is photoelectrically converted by the columns of the photosensor arrays 15a to 15c and is extracted as an electric signal. At this time, by adjusting the thickness of the transparent circuit board 4 and the formation position of the color filters 10a to 10c, the light reaching the row of the photosensor array 15a reaches only the red color filter 10a and reaches the row of the photosensor array 15b. The light passes only through the green color filter 10b, and the light reaching the column of the photosensor array 15c passes through only the blue color filter 10c. Therefore, each photo sensor array 15a-1
In the column 5c, information of only the red component, the green component, and the blue component can be extracted as signals.

The transparent circuit board 4 and the transparent conductor 1
Since No. 1 is employed, the reflected light, which is the image information of the original, is not blocked at all, and information with good reproducibility can be obtained.

Here, each photo sensor array 15a-1
Since the information read simultaneously by 5c is different line information in the document, the correction is performed based on the pitch of each of the photosensor arrays 15a to 15c and the resolution in the reading sub-scanning direction.

The electric signal photoelectrically converted by each of the photosensor arrays 15a to 15c is applied to a flexible substrate 5 on which a circuit component 6 is mounted on a transparent circuit board 4 through signal lines formed by a transparent conductor 11 and a metal film 13. After being subjected to processing such as amplification and gain adjustment, it is delivered to the set side as the output of the color line image sensor.

As described above, according to the present embodiment, the color filters 10a to 10c of the RGB colors are formed at positions where the light beams forming the images do not interfere with each other on the photosensor chips 7a to 7c of each sensor chip row. Therefore, by using the substantially white light source 1, color information of each color can be obtained by one reading operation. As a result, it is possible to increase the document reading speed while using the photosensor chips 7a to 7c for monochrome.

Also, according to the present embodiment, by mounting the photosensor chips 7a to 7c on the transparent circuit board 4, the gap between the adjacently arranged sensor chip rows is reduced to about 0 mm.
Since the lenses can be brought close to each other, the lenses are integrated into one system, and can be used with little influence from resolution, aberration, and the like.

Further, according to the present embodiment, the external dimensions can be made substantially equal to those of the conventional monochrome line image sensor.

[0035]

As described above, according to the present invention, by using a substantially white light source, color information of each color can be obtained by one reading operation, so that a monochrome photo sensor chip can be used. An effective effect that it is possible to increase the document reading speed can be obtained.

As a result, an advantageous effect is obtained that a small and high-speed color line image sensor can be provided at low cost.

Further, according to the present invention, by mounting the photosensor chip on the transparent circuit board, it becomes possible to make the gap between the adjacent sensor chip rows close to about 0 mm. And the resolution,
An effective effect is obtained in that it can be used with little influence from aberrations and the like.

Further, according to the present invention, there is obtained an advantageous effect that the external dimensions can be made substantially equal to those of the conventional monochrome line image sensor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a color line image sensor according to an embodiment of the present invention;

FIG. 2 is an enlarged sectional view showing a main part of the color line image sensor of FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Light source 2 Transparent plate 3 Lens array 4 Transparent circuit board 7a-7c Photosensor chip 10a-10c Color filter 11 Transparent conductor

Claims (1)

[Claims] A transparent plate defining a reading surface of the document; a light source for irradiating a reading surface of the document placed on the transparent plate; and a light source disposed on a path of light reflected from the transparent plate; A lens array for erect imaging of a read image of a document; and a plurality of monochrome photosensors mounted on a transparent circuit board via a transparent conductor, and photoelectrically converting and reading image information formed on the lens array. A red chip formed corresponding to each of the plurality of photosensor chips on a path of light from the lens array to the photosensor chip on a surface of the transparent circuit board opposite to a mounting surface of the photosensor chip; Green, blue 3
A color line image sensor comprising a color filter.