JPS63167556A - Image sensor - Google Patents

Abstract

PURPOSE:To relax the distortion of an image in the vicinity of an edge by using photoelectric transducers arranged to positions except the edge of the photoelectric transducer array so as to apply pitch correction in an image sensor consisting of the arrangement of plural photoelectric conversion element arrays. CONSTITUTION:Photoelectric transducer arrays 1A, 1B arranged with plural photoelectric transducers 2 at a prescribed pitch (a) in one direction are arranged unidirectionally so that the arrays 1A, 1B belong to different arrays and the pitch (a) between the adjacent photoelectric transducers is the pitch (b) larger than the pitch (a). In the image sensor as above, the interval between prescribed elements among the photoelectric transducers 2 arranged at the position other than the edge of the arrays 1A, 1B is selected to be a pitch (c) smaller than the pitch (a) so as to compensate the difference between the pitches (a, b), thereby obtaining an excellent read picture without distortion.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention is applicable to image sensors, especially facsimile machines and QC devices.
The present invention relates to a contact image sensor that is used in -R, etc., and is formed by arranging a plurality of photoelectric conversion arrays.

(Prior art) Image sensors are used in document reading units such as facsimile machines and OCR, but in recent years, close-contact image sensors have been developed in order to make devices smaller and maintenance-free. Progress is underway, and some of them have been put into practical use. This contact image sensor uses a rod lens array in the lens system, and forms an image on the document surface on a photoelectric conversion element array with a length equal to the width of the document in a one-to-one ratio. be. If such a contact type image sensor is used, the imaging distance can be made very short (for example, 16.7 mm), and the device can be made smaller. In addition, unlike conventional lens reduction type image sensors, it has the advantage of having a large light-receiving area, which improves sensitivity and makes it possible to use solid-state light emitting devices such as LEDs as light sources for illumination. It also contributes to maintenance-free operation.

(Problems to be Solved by the Invention) In general, photoelectric conversion element arrays include those formed from thin films of amorphous silicon, CdS, etc., and those formed on silicon single crystals such as CCD image sensors. However, since a contact type image sensor requires a length equal to the width of the document, it is difficult to configure this contact type image sensor with a single chip. In particular, a photoelectric conversion element array formed on a silicon single crystal cannot be made into a very large chip.

For this reason, in a contact type image sensor, a plurality of photoelectric conversion element array chips are arranged in the longitudinal direction, and the length is equal to the width of the document. As methods for arranging them, there are two methods: arranging them in two rows in a staggered manner, and arranging them in a straight line. Since the former method requires correction of the reading line, it is necessary to use the latter method in order not to perform this correction during reading.

However, when a plurality of photoelectric conversion element array chips are arranged in a straight line, a shift in pixel pitch occurs at the joint between each array. Therefore, some kind of correction must be made for this pixel pitch deviation. FIG. 2 is a configuration diagram of a conventional image sensor in which a plurality of photoelectric conversion element array chips are arranged in a straight line. In this figure, 2
The vicinity of the joint between two photoelectric conversion element arrays IA and IB is shown. That is, photoelectric conversion element arrays IA and I
B, a plurality of photoelectric conversion elements 2 (that is, each pixel) are arranged at a standard pitch a, and adjacent photoelectric conversion elements 2 at the seam have a pitch b (here, baa
). In order to correct the pitch deviation at this seam, the pitch of the photoelectric conversion elements 2 at the ends of both photoelectric conversion element arrays IA and IB is set to pitch C (here, C<a
). Now, if the pitch of any n sections at the end is defined as the pitch C, and the pitch C is set to be 2nc + b - (2n+1)a, the pitch deviation can be corrected. In the example of FIG. 2, it is nm3.

However, in the conventional image sensor as described above, since the pitch fluctuates drastically at the end of the photoelectric conversion element array, image distortion occurs in the portion of the read image information corresponding to the end position. In particular, when reading diagonal lines, there is a problem in that seams appear on the diagonal lines.

Therefore, an object of the present invention is to provide an image sensor that can obtain high-quality read images with as little distortion as possible.

[Structure of the invention]

C) A feature of the present invention is that a photoelectric conversion element array in which a plurality of photoelectric conversion elements are arranged at a predetermined pitch a in at least one direction,
In an image sensor in which a plurality of photoelectric conversion elements are arranged in one direction so that the pitch between adjacent photoelectric conversion elements belonging to different arrays is pitch b, which is larger than pitch a, a photoelectric conversion element is placed at a position other than the end of each photoelectric conversion element array. The spacing between predetermined elements of the arrayed photoelectric conversion elements is set to pitch C, which is smaller than pitch a, to compensate for the difference between pitch a and pitch b, and a high-quality read image without distortion can be obtained. This is how it was done.

(Function) According to the present invention, since pitch correction is performed by the photoelectric conversion elements arranged at positions other than the ends of the photoelectric conversion element array, pitch fluctuations are no longer concentrated at the ends, and Image distortion in the vicinity is alleviated, making it possible to obtain a distortion-free and high-quality read image.

(Embodiment) FIG. 1 shows a plan view of the vicinity of a joint of a photoelectric conversion element array constituting an image sensor according to an embodiment of the present invention.

Two photoelectric conversion element arrays IA.

A plurality of photoelectric conversion elements 2 are arranged on the IB at a standard pitch a. The pitch of the photoelectric conversion elements 2 located at the joint between both photoelectric conversion element arrays LA and IB is pitch b (
b>a). In order to correct this pitch deviation, the pitch of some photoelectric conversion elements 2 is made to be pitch C.

However, the difference from the conventional device shown in FIG. 2 is that the portions arranged at this pitch C are distributed and provided in areas other than the ends of the photoelectric conversion element array. In the embodiment shown in FIG.
Photoelectric conversion element array IA.

Both IB and Pitch C sections are provided at two locations. In this embodiment, b-1,2a c-0,958 n store 2 satisfy the above-mentioned formula 2nc + b - (2n+1)a. Moreover, the pitch variation is a~1 at the end.
．． 2a is about 20% at most, and pitch C is a to 0.95a, about 5% at most, which is in any case lower than the 25% recommended by CCITT regarding facsimile. Therefore, distortion in image quality at the seam can be suppressed to the extent that it is almost unnoticeable to the naked eye.

〔Effect of the invention〕

As described above, according to the present invention, in an image sensor formed by arranging a plurality of photoelectric conversion element arrays, pitch correction is performed by the photoelectric conversion elements arranged at positions other than the ends of the photoelectric conversion element array, so that pitch fluctuation is no longer concentrated at the edges, image distortion in the vicinity of the edges is alleviated, and a high-quality read image without distortion can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the vicinity of the joint of a photoelectric conversion element array constituting an image sensor according to an embodiment of the present invention, and FIG. 2 is a plan view of the vicinity of the joint of a photoelectric conversion element array constituting a conventional image sensor. be. IA, IB... photoelectric conversion element array, 2... photoelectric conversion element (pixel). Applicant's agent Sato - Yuu drawing no Jyo v! (No change in content) Body I Figure 2 Figure Procedure Amendment February 5, 1986

Claims (1)

[Claims] 1. A photoelectric conversion element array in which a plurality of photoelectric conversion elements are arranged at a predetermined pitch a in at least one direction, the pitch between adjacent photoelectric conversion elements belonging to different arrays is larger than the pitch a. In the image sensor in which a plurality of photoelectric conversion elements are arranged in one direction so as to have a pitch b, the pitch is the interval between predetermined elements among the photoelectric conversion elements arranged at positions other than the ends of each of the photoelectric conversion element arrays. a
An image sensor characterized in that the pitch c is smaller and the difference between the pitch a and the pitch b is compensated for. 2. The image sensor according to claim 1, characterized in that photoelectric conversion elements arranged at a pitch c are provided in a distributed manner.