JPS63288059A - Image sensor - Google Patents

Abstract

PURPOSE:To remove a defect in which the pinholes, etc., of a photosensitive body are easy to be generated, and to obtain large photocurrents by forming first and second electrodes at a specified distance on the photosensitive body on the surface including the photosensitive body and shaping a light-transmitting window for applying irradiation beams from the rear of a substrate. CONSTITUTION:A light-shielding film 2 is formed onto one surface of a transparent substrate 1 consisting of quartz glass, etc., by an opaque thin-film composed of Cr, Si, Ge, Mo, etc., and an insulating film 3 is shaped onto the light-shielding film 2 when the light shielding film 2 is made up of a conductive material. A photosensitive body 4 consisting of group II-VI elements is shaped, and shaped to a beltlike shape through a photoetching method, a conductive film is formed by a conductive material such as Al including the surface of the beltlike photosensitive body 4, and a first electrode 5 having a shape corresponding to the beltlike photosensitive body 4 and a plurality of second electrodes 6 held and disposed on the photosensitive body 4 at spaces of approximately 10mum from the first electrode 5 are formed through the photoetching method in the conductive film. A light-transmitting window 9 for irradiating a draft 8 with irradiation beams 10 from the rear of the transparent substrate 1 is formed into the first electrode 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to, for example, arranging a plurality of photosensors on a transparent substrate, illuminating a VA placed on the transparent substrate from below the transparent substrate, and converting the reflected light into light. This relates to an image sensor that receives light and reads a document.

Conventional technology For reading documents such as facsimiles, attempts are being made to reduce the size, use pumice, and lower the cost by using a fully contact image sensor that does not have an imaging element such as a SELFOC lens between the document and the sensor. There is. A complete contact type image sensor reads the original by placing the image sensor in direct contact with the original, irradiating the original with illumination light from the sensor surface, and reading the reflected light of the illumination light from the original.

The conventional basic configuration and operation will be explained using FIG. 2.

Glass is used as the transparent substrate 11, and a photoreceptor 14 for charge conversion is provided on the surface in the form of a band.
It has a sandwich-type structure sandwiched between two layers 6 and 6, and is brought into close contact with the original M18 with a transparent protective film 17 interposed therebetween. Each photoelectric conversion unit has a photoconductor 14 formed of the first electrode 15, the second electrode 16, and an a-3i film.
Translucent v through n! 19 is provided, irradiation light 20 is introduced from the back side of the transparent substrate 11 opposite to the surface on which the element array is provided, and the irradiation light 20 reaches the surface of the original 18.
reflected light is received. That is, the reflected light is scattered to some extent by the surface of the original document 18 and is received by a sandwich type photoelectric conversion section formed around the transparent window 19.

Problems to be Solved by the Invention In the above charging conversion section, the first electrode 15 on the light incident side
In order to guide the reflected light to the band-shaped photoreceptor 14 sandwiched between the second electrode 16 and the second electrode 16, and read the intensity of the reflected light, a second electrode on the light incident side is used.
The electrode 16 must be a transparent electrode. IT usually consists of indium and tin as transparent electrode materials
Although an O film or the like is used, the production conditions are strict and it is difficult to produce a stable film. In addition, in the sandwich type photoelectric conversion section as described above, in order to prevent carriers generated by light from traveling in the S thickness direction and from disappearing at the electrode section, a semiconductor P I N 41Le or shot L-converter is used. L rehole, tj, and λ·11 blocking structure 4 must be formed in the L CF electric r at the right or wrong γ-. This 411 structure does not allow injection current to flow and detects current only due to carriers generated by light irradiation, so it is not possible to obtain a very large photocurrent. Further, since it is a sandwich type, there are problems such as defects caused by pinholes in the photoreceptor 14 being easily photoelectrically generated.

Since the present invention solves the above problems, it is possible to eliminate defects that are likely to occur due to pinholes in the photoreceptor by eliminating the structure in which the photoreceptor is sandwiched from above and below, and it is also possible to generate a large photocurrent. Signal processing is also good! The object of the present invention is to provide an image sensor capable of performing 11111 images.

Means for Solving the Problems ゛The above-mentioned problems of the conventional art can be solved by forming the photoelectric conversion section using planar parallel electrodes. forming a light-shielding layer while insulating the light-shielding layer, forming a photoreceptor on the surface thereof, and forming first and second electrodes on the surface including the photoreceptor at a predetermined distance apart from each other on the photoreceptor; A light-transmitting window is formed on a part of the first electrode on the photoreceptor and a corresponding part of the light-shielding film for irradiating light from the back surface of the substrate. The original is read by transmitting reflected light into the gap between the first and second electrodes and detecting the intensity of the light.

Function: With the above configuration, carriers generated by light travel in a direction parallel to the WA thickness, so a large photocurrent can be obtained, and it is also less susceptible to defects such as pinholes in the photoreceptor. Therefore, the yield during mass production can be improved, and characteristics can be easily made uniform. Furthermore, there is no need to form a transparent electrode, which has a rough composition and is difficult to create, and there is no need to create a blocking structure, so the creation process is simpler and less expensive than when creating a charging converter up to PIN411. It becomes possible to realize an inexpensive image sensor.

Example An embodiment of the present invention will be described below based on the drawings.

In FIG. 1, a light-shielding film 2 is formed on one surface of a transparent substrate 1 such as quartz glass using an opaque thin film of Cr, Si, Qe, Mo, etc., and if this light-shielding film v2 is a conductive material, this An insulating film 3 is formed on the light shielding film 2. On top of that, a-3i or CdSe, CdS, CdTe, Zn5
e.

ZnTe! , a photoreceptor 4 made of a II-W group element such as ZnS is formed, and this is shaped into a band shape by photolithography.
A conductive film is formed from a conductive material such as 8Ω on the surface of the strip-shaped photoreceptor 4, and this electrical film is formed into a first electrode 5 having a shape corresponding to the strip-shaped photoreceptor 4 by photolithography. ,
A plurality of second electrodes 6 are formed on the photoreceptor 4 so as to maintain an interval of about 10 μm on the first electrode 5 . The photoelectric conversion section constructed in this way is exposed to the original 8 via the protective film 7. A light-transmitting window 9 for irradiating illumination light 10 onto the original 8 from the surface of the transparent substrate 1 is formed in the first electrode 5.

When light is irradiated into the above-mentioned gap of about 10μ, the electrical resistance of the photoreceptor 4 in the gap changes, and the first electrode 5 and the second electrode
By applying a voltage between the electrodes 6, this change in electrical resistance can be detected by the current value.

Therefore, by irradiating the original M8 with light and guiding the reflected light from the original 8 to the gap, the original 8 can be read. By forming a plurality of electrodes 6 and sequentially switching applied voltages using a switching circuit, the device operates as an image sensor.

In this embodiment, the band-shaped photoreceptor 4, the insulating film 3, and the light-shielding film 2 formed under the electrode are removed by photoetching or the like in correspondence with the position of the window formed in the first electrode 5, and the light-transmitting window is removed. form 9. In addition, when the image sensor section created in this way is used by directly attaching it to the document 8, the first electrode 5 and the second electrode 6 of the charging conversion section will wear out, so it is necessary to protect them. Therefore, SiO2, 8iN is applied to the surface.

Transparent protection W1 such as 5iON, SiC, diamond film, etc.
7 is formed.

Effects of the Invention According to the present invention, since the charge conversion portion of the complete contact type image sensor is formed of a flat electrode, the manufacturing becomes easy and the Vi degree of the manufacturing is improved. In addition, compared to electrodes that sandwich the photoreceptor from above and below, it is less susceptible to defects such as pinholes in the photoreceptor, has uniform characteristics, and improves mass productivity. Furthermore, since the planarized photoelectric conversion section can receive a large photocurrent, signal processing is also intermediate. Therefore, it is possible to reduce the cost including the peripheral circuits.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are a plan view of a main part showing an image sensor according to an embodiment of the present invention, a sectional view thereof taken along line A-A, and FIG.
A) and (b) are a plan view J3 of main parts of a conventional image sensor and a sectional view taken along line B-8 thereof. 1... Transparent substrate, 2... Light shielding film, 3... Insulating film,
4... Band-shaped photoreceptor, 5... First electrode, 6... Second electrode, 7... M retention film, 8... Document, 9... Transparent window, 10... ...Irradiation light. Agent Yoshihiro MorikiFigure 2

Claims (1)

[Claims] 1. Form an electrically insulated light-shielding layer on a substrate, form a photoreceptor on the surface, and place a predetermined distance above the photoreceptor on the surface including the photoreceptor. forming first and second electrodes separated from each other, and irradiating a part of the first electrode on the photoreceptor and a corresponding part of the light shielding film with irradiation light from the back surface of the substrate; An image sensor with a transparent window. 2. The image sensor according to claim 1, wherein a plurality of second electrodes are formed, and a plurality of light-transmitting windows are formed accordingly. 3. The image sensor according to claim 1, wherein the photoreceptor is made of amorphous silicon or a II-VI group element. 4. The image sensor according to claim 1, wherein the first electrode and the second electrode are formed of the same material.