Device for reading an image having a common semiconductor layer

Abstract

A device for reading an image (an image reading device) according to this invention comprises therein at least one photoelectric conversion semiconductor device provided on a substrate and at least one thin film transistor circuit element provided on the substrate wherein said photoelectric conversion semiconductor device and said thin film transistor circuit element comprise semiconductor regions obtained from one semiconductor film provided on said substrate. The device for reading an image is produced by a process comprising the steps of: depositing a semiconductor material on a substrate; forming a photoelectric conversion semiconductor device on said substrate, a semiconductor region of said photoelectric conversion semiconductor device being made of said semiconductor material; and forming a thin film transistor on said substrate, a semiconductor region of said thin film transistor being made of said semiconductor material, wherein said thin film transistor constitutes an electric circuit required to read an image.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]This invention relates to a device for reading an image (an image reading device), and more particularly to a device for reading an image (an image reading device) having photoelectric conversion devices arranged in a transverse direction to an original, which is usable for a facsimile machine, an image reader, a digital copying machine and the like.[0003]2. Description of the Prior Art[0004]As this type of image reading apparatus as described above have been conventionally known three types of image reading devices such as a non-contact type, a close contact type and an entirely-close contact type. Recently, in association with requirement for a compact and lightweight type of facsimile machine, image reader, digital copying machine or the like, the image reading apparatus itself is required to be compact and lightweight. This requirement causes the close contact and entirely-close contact types to be mainly propagated...

AI Technical Summary

Benefits of technology

[0011]In order to overcome the above disadvantagedisadvantages of the prior art, an object of this invention is to provide a device for reading an image (an image reading device) which has a compact structure, high photoresponsibility and highly-effective photosensitivity and is capable of reading out an image with high precision and high gradation.

[0015]The photoelectric conversion device and the thin film transistor are formed of the same semiconductor film, and formation of impurity semiconductor regions of the photoelectric conversion device and that of the thin film transistor are carried out at the same time, e.g. by ion implantation, thereby implementing simplification of a manufacturing process and reduction of a manufacturing cost.

[0019]Further, the semiconductor film may be composed of semi-amorphous or semi-crystal semiconductor. In this case, the semiconductor film has a long diffusion length which can not be obtained by amorphous semiconductor, and a large absorption coefficient which is not obtained by monocrystal or polycrystal semiconductor. Therefore, the semiconductor film can be thinned and the photoelectric conversion device having a long diffusion length can be manufactured.

[0021]In the photoelectric conversion device thus constructed, those carriers which are generated in a photoelectric converting area between the P-type and N-type diffusion regions can be effectively outputted to the outside because of the long diffusion length of the semiconductor layers. In addition, since the P-type and N-type impurity regions are formed in a direction of depth (in a laminating direction) of the same semiconductor film from the light-irradiating surface of the semiconductor film, the intensity of the irradiated light is constant in the direction of the electric field between the P-type and N-type impurity regions, so that photoelectric conversion efficiency is improved.

Problems solved by technology

However, a more compact and lightweight of image reading device has been further required for these types.

As a result, it is difficult to effectively generate electrons / holes in the conventional photoelectric conversion device and output them to the outside.

Further, the photoelectric conversion device using amorphous semiconductor has a disadvantage that it is difficult to effectively take out carriers generated in the semiconductor by light irradiation to the outside because the semiconductor material has a short diffusion length.

As described above, miniaturization, high photoresponsibility and effectivity of photosensitivity have been insufficient to the conventional image reading device, and thus a further development has been required for the conventional image reading device.

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