JPS6281056A - Lensless contact type image sensor - Google Patents

Abstract

PURPOSE:To photoelectrically convert efficiently the scattered light in the titled image sensor by forming an dielectric protective layer to the shielding layers, photoelectric transducers split bilaterally with a slit as the center and ladder-type lead electrodes for the transducers. CONSTITUTION:The titled image sensor is constituted by a method wherein light-shielding layers 3 to be formed with an optical slit 2 which introduces the light to be emitted to the sensor in such a transparent substrate 1 as a glass substrate and striplike photoconductive films 4 which are divided by the slit 2 into two on the said shielding layers 3 interposing an insulating protective layer 5 between them are respectively adhered on the substrate 1, the photoconductive films 4 adhered are separated off by element split grooves 8 to form photoelectric transducers 7 in a linearly arranged constitution and furthermore, ladder-type lead electrodes 6 for the converters 7 are formed in order. The light is introduced from under the substrate 1 in the vertical direction. The photoconductive films 4 receive the reflected scattered light, yet the conductivity and resistivity of the films 4 are changed by the light receiving, whereby a sensor output can be obtained. That is, a change in the resistance of the photoconductive films 4 to be disposed bilaterally of the photodetecting window is detected by the lead electrodes 6. If an electrode scanning for reading out the said sensor is executed in the arrangement directions of the ladder-type lad electrodes 6 for the transducer 7, the sensor output having a large change in the photo output becomes available.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a thin-film optical sensor using IC technology such as COD, for example, an optical sensor that reads out a same-magnification image used in a facsimile machine, and in particular, a Cd that is intended to reduce the size of the sensor head.
This paper presents a method for configuring a conductive film for photoelectric conversion made of Se or CdS.

[Industrial application field]

The present invention relates to a lensless close-contact type image sensor that reads out a same-magnification image by being brought into close contact with a printed document such as characters or images.

Lensless contact type image sensors capable of reading patterns at 1:1 with the original have already been proposed as, for example, the contact type image sensor (Japanese Patent Publication No. 57-78263) or the optical sensor array (Japanese Patent Publication No. 5B-40856).

During reading, the sensor allows light to enter obliquely through a transparent window and receives reflected light or scattered light from an image with a linear dot array element made of a photoconductive film such as CdS, thereby obtaining image information. This sensor can be put into practical use because it can use a simple light guide system such as a focusing fiber element instead of the conventional lens optical system, and the volume of the sensor system can be reduced to about 1/8. It is attracting attention.

The present invention was proposed based on the need to realize a configuration for efficiently photoelectrically converting scattered light in such an image sensor.

[Conventional technology]

FIGS. 7 and 8 are a side sectional view and a front view of the proposed image sensor.

Its configuration and operation will be explained according to the diagram.

In both figures, an insulating light-shielding layer 21 is placed on a glass substrate 23 except for the transparent window 22, and CdS is placed on top of the insulating light-shielding layer 21.
A photoconductive film dot element 25 of the photoelectric effect type made of CdS or CdS is formed. Further, a lead electrode 26 which is opaque to light is formed in a ladder shape with respect to the photoconductive film dot element 25, thereby forming a sensor element.

Further, the dot element 25. The surface of the tone array on which the lead electrodes 26 are formed is covered with a transparent protective layer 27 to form a protective film that protects the sensor element from scratches on the original document 20 to be read and protects it from electrical deterioration.

The photoelectric conversion element 25 on the substrate 23 is configured to receive reflected light from the original 20 caused by a light beam 24 emitted from a solid-state light source or a fluorescent lamp, and photoelectrically convert the received light.

[Problems to be Solved by the Invention] The conventional contact type image sensor receives reflected and scattered light from the document 20, but as shown in FIG.
However, the problem is that the light receiving efficiency is poor and the photoelectric conversion output required for facsimile operation is not sufficient.

[Means for solving problems]

FIG. 1 is a front view of the element showing the basic structure of the contact type image sensor of the present invention. Further, FIG. 2 is a cross-sectional view of the element taken along index line AA and index line B-8 in FIG. 1, respectively.

Slit 2 that guides sensor light to a transparent substrate l such as glass
A light shielding layer 3 is formed, and an insulating protective layer 5 is formed on one of the shielding layers 3.
A band-shaped photoconductive film 4 divided into two by the slit 2 is deposited through the slit 2, and the deposited photoconductive film 4 is separated by the dividing groove 8.
This is a lensless contact type image sensor in which photoelectric conversion elements 7 are separated and linearly arranged, and ladder-shaped lead electrodes 6 are sequentially formed for the photoelectric conversion elements 7. .

[For production]

The photoconductive film 4 divided around the optical slit 2 absorbs reflected and scattered light (not shown) of the original incident from the slit 2.
Since the structure is such that the signal light (signal light read by the sensor) is captured on the left and right or front and rear, the light receiving sensitivity of the photoelectric conversion elements 7 separated by the dividing grooves 8 is significantly improved.

If the sensor reading electrode is scanned in the arrangement direction of the ladder-shaped lead electrodes 6 relative to the photoelectric conversion element 7 (in the vertical direction in the figure), a sensor output with a high optical output voltage will be extracted.

〔Example〕

An embodiment of a contact type image sensor according to the present invention will be described below with reference to FIGS. 3 to 6.

FIG. 3 shows that after a shielding layer 3 made of, for example, a chromium (Cr) vapor-deposited layer is pre-layered on the entire surface of the transparent substrate l except for 2 portions of slits having a width of 9 and 10, a layer of silicon oxide (Si), for example, is deposited on the chromium shielding layer 3. Oz Ft, silicon nitride Si
A light-transmitting layer N5 having good insulation properties is formed, such as an N2 layer or an alumina oxide layer.

Next, it is a plan view of the substrate at a stage in which a photoconductive film 4 containing CdS or CdSe as a main component is sequentially formed by a mask evaporation method or a mask sputtering method.

The width IO of the slit 2 in FIG. 3 is, for example, about 220 μm.

The photoconductive film 4 is divided into approximately two equal parts by the slit 2, and the left and right film widths are equal, and the total width 11 is 5.
It is formed at about 00 to 1000 pm.

Next, the photoconductive film 4 is inserted into the detection window 12' shown in FIG.
, and a photoresist mask pattern having grooves 8' dividing the conductive film into dots.

Also, by performing an etching process after exposure.

Photoconductive element 7 divided into dots by grooves 8 as shown in FIG.
and a plurality of light detection windows 12 of the element 7 are generated simultaneously.

The arrangement pitch of the photodetecting windows 12 is approximately 130 μm. That is, 8 sensor dots are arranged per 164.7)4 squares.

FIG. 5 is a front view of a substrate on which ladder-shaped lead electrodes are formed with respect to the sensor forming substrate of FIG. 4 on which the photodetection window 12 and the like are formed.

The lead electrodes 6 and 6' can be easily formed by a so-called lift-off method in which a conductive film is deposited on the surface of a substrate on which a resist pattern is formed, and then the resist is peeled off.

The substrate on which the lead electrodes shown in FIG. 5 are attached becomes the contact type image sensor of the present invention by finally coating the second insulating protective layer 9 (see FIG. 2).

The sensor formed by said means is transmitted through the light detection window 12 of the slit 2 as shown in FIG. Light is introduced vertically from below Fj,1. The photoconductive film 4 receives reflected and scattered light that changes depending on whether the original is black or white (not shown), and the sensor output is obtained by changing the conductivity or resistance of the film 4.

That is, in one aspect of the present invention, the change in resistance of the photoconductive film 4 disposed on both the left and right sides of the photodetection window is detected by the lead electrodes 6 and 6'.

If the sensor reading electrodes are scanned in the arrangement direction of the ladder-shaped lead electrodes 6 relative to the photoelectric conversion element 7 (in the vertical direction in the figure), the sensor output with a large change in the previous output will be extracted.

〔Effect of the invention〕

According to the contact type image sensor of the present invention.

Since a photoconductive film is formed on both sides of the optical slit to capture the reflected and scattered light of the if^ readout with an extremely simple structure, the light receiving efficiency of the sensor, which was a problem in the past, has been improved, and therefore the light with high photoelectric conversion output can be realized. A sensor will be realized.

The present invention has a great industrial effect from the viewpoint of cutting.

[Brief explanation of drawings]

FIG. 1 is a front view of the element showing the basic configuration of the image sensor of the present invention. FIG. 2 is a sectional view taken along line A- and line B-B in FIG. 1. FIG. 3 is a plan view of forming a photoconductive film. FIG. 4 is a plan view of dot dividing grooves and photodetection window formation. FIG. 5 is a plan view of the formation of ladder-like lead electrodes. FIG. 6 is a front view showing the punching mask pattern for the light detection window etc. shown in FIG. 4. FIG. 7 is a side view of a conventional image sensor. FIG. 8 is a front view of the image sensor of FIG. 7. In the figure, 1 is a transparent substrate and 2 is a slit. 3 is a shielding layer, and 4 is a photoconductive film. 5 is an insulating protective layer, and 6 is a lead electrode. 7 is a photoconductive element and 8 is an element dividing groove. A Mejise, Mbu Kiyosesuke'' surface view 2nd concave!! Figure i5

Claims (1)

[Claims] A shielding layer (which forms a slit (2) on a transparent substrate (1))
3), an insulating protective layer (5) for the shielding layer (3), a photoelectric conversion element (7) divided left and right about the slit (2), and a ladder-shaped lead for the photoelectric conversion element (7). A lensless close-contact image sensor characterized by forming an electrode (6).