JPH0448781A - Image sensor integrated with light source and its manufacture - Google Patents

Abstract

PURPOSE:To prevent a flare by which an output is generated at a photodetector only by turning on an EL light-emitting element and to reduce a dark output by a method wherein a gas layer is laid on the photodetector side of the EL light-emitting element and interface states on both side faces of a transparent substrate are set so as to be the same. CONSTITUTION:The whole surface of an insulating substrate 1 is coated with an adhesive in which spherical spacers 31 have been mixed and dispersed; an adhesive layer 30 is formed; a transparent substrate 2 is arranged in such a way that light-incident windows 26 are faced with individual photodetectors 10; a uniform pressure is exerted on the transparent substrate 20. Both are bonded. Since the film thickness of metal electrodes 25 is made thick, the depth of grooves of the light-incident windows 26 can be made deep. The adhesive does not creep to the side of a dielectric 24 of the light-incident windows 26 and a gas layer 40 can be formed at this part. The whole of reflected light which is reflected totally on the side face of a source document 100 on the transparent substrate 2 out of light emitted to the side of the source document from a light-transmitting layer 23 is again reflected totally at the interface between the transparent substrate 2 and the gas layer 40 and is not incident on the individual photodetectors 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (Prior Art) Conventionally, a contact type image reading device used in a facsimile, a scanner, etc. uses a fluorescent lamp light source, an image sensor having an original width, and an image sensor that captures light reflected from the original into an image. It consists of a same-magnification optical system that forms an image on the sensor, and the light signal from the reflected light according to the density from the original is accumulated as an electrical signal in the light receiving element of the image sensor arranged in a straight line, and this electrical signal is transmitted in a time series. This is to obtain an image signal corresponding to one line (main scanning direction) of the document. According to this image reading device, the size of the device can be reduced compared to a method using a reduction optical system, but there is a limit to how small the device can be made because a rod lens array, etc. is used as the same-magnification optical system. There was a drawback.

Therefore, an ultra-compact light source-integrated image sensor has been proposed that uses an EL light emitting element as a light source and integrates the EL light emitting element and a contact type image sensor.

For example, as shown in FIG. 4, this light source integrated image sensor includes a plurality of light receiving elements 10 arranged in a line on an insulating substrate 1, and an EL light emitting element formed on a transparent substrate 2 made of glass or the like. 20 are arranged to face each other with a translucent adhesive layer 30 in between.

The light emitted from the EL light emitting element 20 illuminates the surface of an original (not shown) placed on the side of the repulsion light element of the transparent substrate 2, and the reflected light enters the light receiving element 10.

(Problem to be Solved by the Invention) According to the light source integrated image sensor having the structure described above, the refractive index n2 (about 1°5) of the transparent glass substrate 2,
The refractive index n3 (about 1.4) of the general adhesive layer 30 and the refractive index n of air satisfy n2≧n>n, which is 1.0. Since it is considered that air exists between the transparent substrate 2 and the document surface (the document is not in complete contact with the transparent substrate 2), the angle of the light emitted from the EL light emitting element 20 is determined by the following formula. 03 or more will be totally reflected by the surface of the transparent substrate 2 on the document side.

θ, -s in -' (n+ /n,) Also, among the totally reflected light, the light below the angle θ shown by the following formula is the light that is not totally reflected at the interface and is formed on the EL light emitting element 20. The light passes through the entrance window 26 and enters the light receiving element 10 .

θ2-s s n -' (n3 / n2) Since the total internal reflection mentioned above occurs regardless of the presence or absence of the original, E
Just by lighting the L light emitting element 20, a part of the EL emitted light always enters the light receiving element 10 (flare), and the dark output of the light receiving element 10 becomes higher than the ground level, narrowing the dynamic range of the light receiving element 10. However, there was a problem in that it was inconvenient when reading multiple gradations.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a structure and manufacturing method thereof that prevents flare in which an output is generated in a light receiving element simply by lighting up an EL light emitting element in an image sensor with an integrated light source. shall be.

(Means for Solving the Problems) In order to solve the problems of the conventional example described above, the invention according to claim 1 provides a method using a plurality of light-receiving elements formed on an insulating substrate and a light-emitting element formed on a transparent substrate. and are arranged to face each other with a light-transmitting layer in between, and the light from the light emitting element is irradiated onto the document surface arranged on the repulsion light element side of the transparent substrate, and the reflected light is incident on the light receiving element. The light integrated image sensor is characterized in that part or all of the light-transmitting layer on the light-receiving element is removed, and a gas layer facing the light-emitting element is interposed.

Further, a method of manufacturing a light source integrated image sensor according to a second aspect of the present invention is characterized by comprising the following steps.

In the light receiving element forming step, a light receiving element is formed on an insulating substrate.

As a light emitting element forming step, a transparent electrode, a dielectric layer 1 light emitting layer, a dielectric layer, and a metal electrode are sequentially laminated on a transparent substrate, and a light entrance window is provided on the metal electrode to form an EL light emitting element.

In the adhesion process, an adhesive is applied onto the insulating substrate on which the light receiving element is formed, and while the gas layer is maintained on the dielectric layer side of the light entrance window, the light receiving element and the EL light emitting element are placed opposite each other to the light entrance window. Glue as shown.

(Function) According to the present invention, a gas layer is interposed on the side of the EL light emitting element and the light receiving element, and the interface state on both sides of the transparent substrate is set to be the same. All the light totally reflected at the substrate interface is totally reflected again at the interface between the EL light emitting element and the gas layer, and does not enter the light receiving element side.

(Example) An example of the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional explanatory diagram of a light source-integrated image sensor according to an embodiment taken along the main scanning direction.

This light source-integrated image sensor consists of an image sensor in which a large number of light receiving elements 10 are formed in a line on an insulating substrate 1, and an EL light emitting element 20 formed on a transparent substrate 2, which are bonded together using a transparent material. It is configured with a chemical layer 30 sandwiched therebetween.

The image sensor includes a large number of individual electrodes 11 . A band-shaped photoconductive layer 12 covering the individual electrodes 11. Strip-shaped common electrodes 13 are sequentially laminated to form a photoconductive layer 1.
2 between the individual electrodes 11 and the common electrode 13 constitutes each light receiving element 10.

The EL light emitting element 20 includes a transparent electrode 21. on a transparent substrate 2 having a substrate thickness of 100 μm. Insulating layer 22゜Light emitting layer 23. Insulating layer 24. It is constructed by sequentially stacking metal electrodes 25. The metal electrode 25 is provided with a rectangular light incident window at a position corresponding to each light receiving element 10 so that the light emitted from the light emitting layer 23 is reflected on the document surface 100 and the reflected light is incident on the light receiving element 10. 26 is formed with an opening.

Further, the film thickness of the metal electrode 25 is a normal film thickness (0.5~
1 μm) to be thicker (about 3 μm), and the light entrance window 2
6, a thin (about 3 μm) gas layer 40 filled with a low refractive index material is interposed between the adhesive layer 30 and the insulating layer 24. The gas layer 40 contains air (refractive index 1.000), argon (refractive index 1.0003), nitrogen (refractive index 1.0003), and helium (refractive index 1.000).
04), neon (refractive index 1.00007), or other gas having a refractive index of approximately 1600 is filled.

The adhesive layer 30 contains a mixture of spherical spacers 31, and maintains a constant distance between the EL light emitting element 20 and the light receiving element 10 (about 90 μm in this embodiment).

Next, a method of manufacturing the above-mentioned light source integrated image sensor will be explained.

A plurality of individual electrodes (chrome patterns) 11 are arranged on the insulating substrate 1 in the left-right direction in FIG. Amorphous silicon (
a-5i)12. Band-shaped transparent electrodes (ITO) 13 are sequentially stacked to form light-receiving elements 10 arranged in an array.

A transparent electrode 21 made of ITO, In, O, 5nO7, etc. is formed on the transparent substrate 2. Y, Ol, Si, N,.

Insulating layer 22 made of BaTiOs or the like. A light emitting layer 23 made of ZnS:Mn or the like. Insulating layer 24 as above. Transparent metal electrodes 25 made of metal such as aluminum are sequentially laminated to form an E
An L light emitting element 20 is formed, and the metal electrode 25 is etched by photolithography to form a light entrance window 26 corresponding to the light receiving element 10. At this time, the metal electrode 25 is deposited thicker than usual (about 3 μm).

Adhesive in which spherical spacers 31 (for example, Micro Pearl SP manufactured by Tsukiki Fine Chemical Co., Ltd.) are mixed and dispersed (
Made by Toray Silicone J CR6123, Made by Sumira Chemical
5X2016 etc.) on the entire surface of the insulating substrate 1 to form an adhesive layer 30, and the transparent substrate 2 is arranged so that the light incidence window 26 faces each light receiving element 10.
Adhesion of both is performed by applying uniform pressure on the 0. At this time, since the thickness of the metal electrode 25 was increased, the light incidence window 26
The depth of the groove can be increased, the adhesive does not penetrate to the dielectric 24 side of the light entrance window 26, and a gas layer 40 is formed in this part. The spherical spacer 31 is made of true spherical hard plastic particles and has heat resistance and insulation properties.

The gas retained in the gas layer 40 depends on the environment in which the bonding process is performed. That is, the gas layer 40
To form an air layer, the bonding process may be performed in a dry air environment. In addition, in order to create a gas layer other than air, the insulating substrate 1 and transparent substrate 2 are placed in a glove box, and -
After creating a vacuum, the glove box may be filled with a desired gas (argon, nitrogen, helium, etc.), and the bonding process may be performed therein.

Finally, the adhesive is cured at 150° C. for 1 hour.

According to the light source integrated image sensor described above, the gas layer 40 is interposed on the light receiving element side 10 of the EL light emitting element 20, and the interface state on both sides of the transparent substrate 2 is set to be the same, so that the light emitting layer 23 Of the light emitted toward the document 100 side, all of the reflected light that is totally reflected on the document side surface of the transparent substrate 2 (the top surface of the transparent substrate 2) is reflected at the interface between the transparent substrate 2 and the gas layer 40 (the bottom surface of the transparent substrate 2). It is totally reflected again at each light receiving element 10.
It is designed so that it does not enter.

Further, since the thickness of the gas layer 40 is set to be a thin layer of about 3 μm, the light 200 that is reflected by the document 100 and passes through the gas layer 40
(containing image information of the original) is refracted at the interface between the gas layer 40 and the adhesive layer 30, and this refracted light is prevented from reaching a position far away in the main scanning direction. As a result, when focusing on one light-receiving element 10, the light that has passed through the light-incidence window far away from the light-incidence window 46 directly above this light-receiving element, that is, unnecessary light that should not originally be incident on the light-receiving element of interest, is the relevant light. It is possible to prevent the light from entering the light-receiving element of interest and to prevent the resolution (MTF) of the light-receiving element from decreasing.

Further, according to this embodiment, among the reflected light from the original 100, light having an incident angle larger than the angle θ1 described above cannot reach the light receiving element 10 (it is totally reflected on the lower surface of the transparent substrate 2), Resolution (MTF) can be improved.

FIG. 2 shows another embodiment of the present invention, in which parts having the same configuration as in FIG. 1 are given the same reference numerals.

In this embodiment, the metal electrode 25 of the EL light emitting element 20 has a normal thickness (0.5 to 1 μm), and a band-shaped gas layer 40 is formed on the light receiving element 10.

This light source-integrated image sensor is manufactured by forming an EL light emitting element 20 on a transparent substrate 2 in a normal process, and using an emulsion-thick screen mask 50 (see FIG. 3(a)) in which two band-shaped openings 51 and 51 are formed. ) is placed on an insulating substrate 1, an adhesive 30' mixed with a spacer similar to the above embodiment is applied, and printed using a squeegee 60 to form a rectangular groove 32 corresponding to the light receiving element array ( Figure 3(b))
.

In FIGS. 3(a) and 3(b), the photoconductive layer 12 and common electrode 13 of the light receiving element 10 are omitted.

The hardness of the squeegee 60 is preferably high so that the thickness of the adhesive layer 30 can be set by the thickness of the screen mask. Further, the thickness of the screen mask 50 is 5 to 30 μm thicker than the diameter of the spherical spacer.

Then, the insulating substrate 1 and the transparent substrate 2 on which the light-receiving elements 10 are formed are placed so that the groove portion 32 (where no adhesive is printed) is located on the light-receiving element array, and the light-incidence window 2 of the EL light-emitting element 20 Pressure is applied uniformly from above the transparent substrate 2 so that the light receiving element corresponds to the angle of 1°, and the two are bonded together. As in the previous embodiment, the type of gas filled in the gas layer 40 is determined by the environment in which this bonding step is performed.

Further, a metal mask may be used instead of the screen mask 50.

(Effects of the Invention) According to the present invention, a gas layer is interposed on the light receiving element side of the EL light emitting element, the interface state on both sides of the transparent substrate is set to be the same, and light is emitted from the EL light emitting element to the original side. EL
By simply turning on the light-emitting element, it is possible to prevent flare caused by output from the light-receiving element, reduce dark output, and widen the dynamic range. Furthermore, by bringing the dark output close to the ground level, the burden on the dark output correction circuit can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an explanatory cross-sectional view showing one embodiment of the present invention, Fig. 2 is an explanatory cross-sectional view showing another embodiment, and Figs. FIG. 4 is a cross-sectional view of a conventional light source integrated image sensor. 1... Insulating substrate 10... Light receiving element 11... Individual electrode 12... Photoconductive layer 13... Common electrode 2... ...Transparent substrate 20...EL light emitting element 21...Transparent electrode 22...Insulating layer 23...Light emitting layer 24...Insulating layer 25 ...Metal electrode 26...Light entrance window 30...Adhesive layer 40...Gas layer Applicant: Fuji Xerox Co., Ltd. Agent Patent attorney Sakamoto Kiyotaka Agent Patent Attorney Tsu Funa
Nobuhiro Figure 2 □ f main scanning direction □ main scanning direction Figure 3 (0) 3rd cause (b)

Claims (2)

[Claims] (1) A large number of light-receiving elements formed on an insulating substrate and a light-emitting element formed on a transparent substrate are arranged to face each other with a light-transmitting layer in between, and light from the light-emitting elements is transmitted to the transparent substrate. In a light source-integrated image sensor in which a document surface placed on a repulsion light element side of a substrate is irradiated and the reflected light enters the light receiving element, part or all of the light-transmitting layer on the light receiving element is removed. An image sensor integrated with a light source, characterized in that a gas layer facing the light emitting element side is interposed. (2) A light receiving element forming step of forming a light receiving element on an insulating substrate, and a transparent electrode, a dielectric layer, a light emitting layer, a dielectric layer,
A light emitting element forming step in which metal electrodes are sequentially laminated and a light entrance window is provided on the metal electrodes to form an EL light emitting element; and an adhesive is applied onto the insulating substrate on which the light receiving element is formed to form a dielectric layer of the light entrance window. A method for manufacturing an image sensor integrated with a light source, comprising: adhering the light receiving element and the light incident window of the EL light emitting element so that they face each other while maintaining a gas layer on the body layer side.