JPS58222661A - Light sensor array - Google Patents

Abstract

PURPOSE:To manufacture easily and economically a long light sensor array with high density, by incorporating the light sensor array and an electrode wiring board. CONSTITUTION:A light sensor array board 3 is constituted by arranging plural photoconductors 2 on one side of a transparent board. Further, the electrode wiring board 4 is constituted by forming an individual electrode group 5 and a common electrode group 6 on the surface of a glass board corresponding to the position of the light sensor array. The light sensor array board 3 and the electrode wiring board 4 are incorporated by opposing a light sensor array forming surface and an electrode forming surface. Further, a light shield film is formed on the surface of the board except a photosensitive part of the light sensor array.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an optical sensor for use in, for example, facsimiles.
The present invention relates to an optical sensor array for reading an image on a transmission original by arranging a plurality of optical sensors in a 1:1 correspondence with the transmission original in order to make the array smaller and more economical.

In conventional applications, a self-scanning image line sensor in which a photodiode array and a circuit for scanning the photodiode array are integrated into an IC is mainly used.

This self-scanning image sensor includes one using a Si photodiode or a phototransistor, and one using a C phototransistor as a sensor.
There is a method using a photoconductive thin film of a compound such as d. The former is typified by the MO8 type image sensor,
It has already been put into practical use.

On the other hand, the latter is still in the stage of practical research. When constructing a facsimile reading scanner using an MO8 type image sensor, the optical sensors that make up the image sensor are arranged extremely densely, so an optical lens is required to obtain the required image resolution and screen width. Therefore, it is necessary to reduce the image of the transmitted document onto the sensor. When a reduction lens is used in this way, a certain distance is required between the document and the sensor, which poses a significant restriction on miniaturizing the apparatus. Furthermore, as the transmission screen width increases, a set of optical lenses and an image sensor are required.
The combination alone cannot cover the entire screen width, and a plurality of combinations are required, which further impedes miniaturization and has the drawback of increasing cost.

One way to improve this drawback is to use optical fibers arranged in a line instead of optical lenses.

In this case, the image sensor to be combined with the optical fiber array must be at least the same length as the optical fiber or longer. For example, if the original to be sent is A4 size, an image sensor with a length of 216 mm or more is required. It becomes necessary.

For such long image sensors, a photoconductor made of a Cd compound or the like is divided into independent islands on an insulating substrate such as glass or ceramic, and arranged in a line, and electrodes are placed on the same substrate in correspondence with each sensor. A structure in which the wires are connected and wired has already been proposed.

In manufacturing an image sensor with such a structure, the division of the optical sensor and the formation of the electrode wiring connected to it are performed by photoetching, so resist coating,
Each step of exposure, development, etching, and resist removal must be repeated under strictly appropriate conditions.

For example, when forming an A4 size image sensor, the sensor is divided into fine islands of 100μ in width and 70μ in length at intervals of 25μ and arranged within a range of 216 mm in length. Forming by photoetching requires a great deal of effort in controlling the conditions of each step as described above, but the yield rate is low. Furthermore, since the electrode wiring to be connected to the optical sensor formed in this manner is also formed by photoetching, the final quality of good products is determined by the accumulation of the quality of good products of each process, and there is a serious problem in manufacturing, such as a significant drop.

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above points, and provides an optical sensor that can be easily and economically manufactured into a high-density and long optical sensor array.

According to the present invention, a photoconductor is deposited on one surface of a glass substrate, and then a plurality of photoconductor islands are divided and formed by photoetching to form a plurality of photoconductor islands arranged in a row on the surface of a glass substrate. A metal film is deposited and photo-etched to form an individual electrode group corresponding to the position of the optical sensor array, and this individual electrode group is divided into a plurality of blocks, with electrodes facing each divided group at a constant interval. After forming a common electrode group, remove only the portion of the electrode corresponding to the photosensitive area of the photosensor where the photosensor array will be located, and coat tin or indium on the tip of the electrode that will be connected to the photosensor. An optical sensor array characterized in that all the optical sensors are brought into corresponding contact with the electrode group formed in such a way as to cover the tips of the electrode group, heated in an inert gas atmosphere, and integrated with an electrode wiring board. is obtained.

In particular, according to the present invention, there is also obtained an optical sensor characterized in that the surface of the optical sensor array substrate of the optical sensor array is coated with a light shielding film except for the photosensitive portion of the sensor.

An embodiment of the present invention will be described in detail below with reference to the drawings.

That is, the optical sensor 2 as shown in FIG. 1 is constructed by depositing a cadmium sulfide thin film on the entire surface of a long transparent substrate, for example, a glass substrate 1, by a chemical deposition method, and then depositing cadmium selenide on the entire surface of the glass substrate 1. Laminated layers are deposited using methods such as sputtering. After that, the glass substrate 1 covered with this laminated film
The mixture was placed in a quartz storage container with cadmium chloride powder, kept in a semi-closed state, and placed in an inert atmosphere such as nitrogen for 500 minutes.
Heat treatment at ~600°C for 30-60 minutes.

By performing this heat treatment, the cadmium sulfide film, which exhibits almost no photosensitivity as a deposited film, comes to exhibit photosensitivity. In addition, since cadmium selenide is laminated, a solid solution film of cadmium sulfide and cadmium selenide is formed, resulting in significantly improved photosensitivity and light response speed compared to a cadmium sulfide film alone. Begins to show characteristics.

Next, the solid solution film formed on the entire surface of the glass substrate 1 is divided by photoetching so as to have the resolving power necessary for a facsimile sensor, and is formed into an array of independent rectangular islands to form an optical sensor and a sensor substrate 3. do.

It is important to appropriately select the dimensions of this island depending on the resolution required for facsimile.

For example, if an A4 size original is set to have a width of 100 .mu., a length of 200 .mu. (however, the photosensitive area is 70 .mu.), and an island spacing of 25 .mu., sufficient resolution can be obtained for a pattern of 8 lines/frame.

As shown in FIG. 2, the electrode wiring board 8 is a glass substrate 4 that is the same or slightly longer than the optical sensor board 3 and has a width that allows sufficient electrode wiring to be formed.

The dimensions of this glass substrate 4 are such that two wiring layers (not shown) are provided at the terminal portion of the individual electrode group 5, which is different from the electrode wirings 5 and 6 as shown in FIG. The size may be such that a matrix-connected wiring structure is provided.

The method for manufacturing the electrode wiring board 8 is to first deposit Ni-Cr, which has good adhesion to glass, on the surface of the glass substrate 4, then palladium, and then gold, in that order, by vapor deposition or sputtering to stabilize the film resistance. 350 in an inert gas atmosphere to measure
Heat treatment is performed at ℃ for 1 hour.

Note that the purpose of interposing palladium is to prevent gold from diffusing into the Ni--Cr layer, and the gold coating is for connection with flexible wiring used for connection with a sensor drive circuit. In order to minimize the wiring resistance, the gold layer is further plated with gold to form a thick film.

Next, the deposited metal multilayer film is divided into an individual electrode group 5 and a common electrode group 6 by photoetching. Individual electrode groups 5 each optical sensor divided and formed on the optical sensor substrate 3
The common electrode group 6 divides the individual electrode group 5 into a plurality of blocks, and the common electrode group 6 faces each divided group at a constant electrode interval. Further, from the electrode wiring formed in this way, only the electrode portion corresponding to the photosensitive area of the optical sensor 2 between the individual electrode group 5 and the common electrode group 6 was removed again by photoetching.
A metal such as tin or indium that melts at a relatively low temperature is coated by plating only on the tip portions of the individual electrode group 5 and the common electrode group 6 where the optical sensor 2 contacts. The optical sensor 2 is placed on the electrode wiring board 8 made in this way so that the surface thereof is in direct contact with the surface of the electrode, and each sensor divided into islands is connected to an individual electrode group 5 and a common electrode group 6. The optical sensor substrates 3 are aligned using a microscope or the like so that they correctly correspond to each electrode and overlap the plated electrode tips 7. Then, in an inert gas atmosphere such as nitrogen at a temperature of 200 to 300°C,
Heat for 0 minutes to form an ohmic connection between the optical sensor and the electrode. In order to strengthen the fixation between the light sensor board 3 and the electrode wiring board 8, an epoxy resin 9 or the like is applied to the margins of both and hardened.

If necessary, as shown in FIG. 4, the surface of the gas 27 on the side of the optical sensor substrate 3 on which the optical sensor 2 is not formed is covered with a light-shielding film 1o, except for the photosensitive part of the sensor. One of the features of the present application is that the coating with the light shielding film 1o can be carried out as an independent process after the completion of the optical sensor array. That is, when it is desired to change the shape and size of the photosensitive portion of the photosensor formed with the same size and size, the modification can be substantially made by changing the size and shape of the light shielding film 1o without changing the photosensor 2.

As described above, according to the method of the present invention, it is possible to easily and inexpensively manufacture a long optical sensor array having a high resolution, which has been difficult with conventional methods. Therefore, by using this optical sensor array, not only can facsimile reading heads be made smaller and cheaper, but also effective for various pattern recognition, optical character reading devices, position detectors, etc. It can be used. In the above embodiment, both of the opposing substrates are transparent, but only the incident light side may be transparent.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an optical sensor board manufactured according to the present invention, FIG. 2 is a perspective view of an electrode wiring board, and FIG. FIG. 4 is a perspective view of a sensor array, and FIG. 4 is a perspective view of an optical sensor substrate coated with a light shielding film in a second embodiment of the present invention. 1...Glass substrate for optical sensor, 2...
・Light sensor, 3...Light sensor board, 4...
... Glass substrate for electrode wiring, 5 ... Individual electrode group, 6 ... Common electrode group, 7 ... Plated electrode tip, 8 ... ...electrode wiring board, 9
... Epoxy resin, 10 ... Light shielding film.

Claims (2)

[Claims] (1) A photosensor array substrate in which a plurality of photoconductors are arranged on one surface of a transparent substrate, and an electrode wiring board in which electrodes are formed on the surface of a second substrate in correspondence with the positions of the photosensor array. is integrated with the optical sensor array forming surface and the electrode forming surface facing each other, and at least one of the first and second substrates is transparent. (2) The optical sensor array according to claim 1, wherein a light-shielding film is coated on the surface of the substrate except for the photosensitive portion of the optical sensor array.