JPS60206061A - Image sensor - Google Patents

Abstract

PURPOSE:To enable the increase in density of picture elements as compared with the density of photoelectric conversion elements by a method wherein filaments are extended out of photoelectric conversion elements opposed to each other, and the part made of this filament and the photoelectric conversion element are made as the picture element. CONSTITUTION:A filament, e.g. a small piece 311 is formed in the part opposed to the photo receiving surface 31 made of a photoelectric convesion element. In other words, the part between adjacent photoelectric conversion elements is of form that one picture element G can be constructed by composition of small pieces 311. This small piece 311 has the area of 1/3 that of the photo receiving surface 31: the picture elements F and G are photo receiving surfaces of the same area. Therefore, with regard to electric outputs corresponding to the picture elements F and G, if the amounts of irradiation light to the picture elements F and G are equal, electric outputs nearly the same can be obtained. Such a construction enables the increase in density of picture elements by a factor of 1.5 times as compared with the density of photoelectric conversion elements, and simplifies the formation of conductor patterns of the drive circuit part, wire bonding, and the like, with the increase in density of picture elements.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an image sensor used in, for example, facsimiles, which converts image information such as a document into a time-series electrical signal, and particularly relates to an improved photoelectric conversion element thereof. Regarding the image Senna.

[Technical background of the invention and its problems]

In recent years, contact image sensors have been actively developed in order to miniaturize image reading devices used in facsimiles and the like. A contact type image sensor is an image sensor in which photodetecting elements are arranged in a row at a desired resolution in the same width as the original, and image information is read by bringing the original close to the original.

FIG. 1 shows an apparatus using a conventional image sensor, and FIGS. 2 and 8 show conventional image sensors.

In Figure 1, the platen roller (1) moves the manuscript paper (
2) is sent out in the sub-scanning direction on the paper guide (3). The image written on the manuscript paper (2) is illuminated by light emitted from a light emitting section (6) fixed to the support body (5). The irradiated image on the original (2) is formed on the photoelectric conversion section of the image sensor (9) via the cylindrical Radlens array (7) fixed to the support body (5). This image sensor (9) is fixed to the support body (9) with a backing (8). The image formed on the photoelectric conversion section is converted into an electrical signal and output from the output terminal section. .

Next, the image sensor (9) will be explained with reference to FIG. In FIG. 2, an image sensor (9) is a photoelectric conversion unit (4) configured on an insulating substrate (21) such as glass.
) and the drive circuit section). In the photoelectric conversion section (g), a plurality of photoelectric conversion elements are arranged in a line in the scanning direction.

The photoelectric conversion element holder is composed of a transparent common electrode 1, a photoelectric conversion film (n), and an individual electrode (2), and an isolation film (c) is formed as necessary.On the other hand, the drive circuit section (B) is It is composed of an integrated circuit element (a) and a conductive pattern (to).The integrated circuit element (a) is fixed on an insulating substrate (goods) using epoxy resin or the like, and if necessary, individual electrodes and conductive patterns (to) ) and gold wire (5).

Next, the photoelectric conversion element of the image sensor (9) will be explained using FIG. In FIG. 8, the conventional photoelectric conversion element has a square or rectangular light receiving surface 0υ.

The light-receiving surface t31) is coupled one-to-one with the individual electrodes (to), and the individual electrodes (24) are connected in accordance with the amount of light irradiated to the light-receiving surface C3).
An electrical signal is output to. By the way, as shown in FIG. 1, in a device using a normal image sensor (9), the pixels of the image formed onto the light amount conversion element by the rod lens array (7) coincide with the light receiving surface C31). It is designed like this. That is, in FIG. 8, F indicates an area constituting one pixel. In an image sensor designed so that a pixel and a light-receiving surface 01) coincide with each other, the output signal of each pixel corresponds one-to-one to each pixel and is output from an individual electrode. As a result, the same number of individual electrodes as the number of pixels is required, and as the pixel density increases, the wiring density of the individual electrodes, conductive patterns (5), and bonded gold wires (5) tends to increase. Therefore, in conventional image sensors, as the pixel density increases, it becomes difficult to form conductive patterns and wire bonding in the drive circuit, and there is a risk of lower manufacturing yields and lower reliability. .

[Purpose of the invention]

In view of the above problems, an object of the present invention is to provide an image sensor in which the density of pixels is higher than that of photoelectric conversion elements.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention is an image sensor in which stripes extend from opposing photoelectric conversion elements, and a portion shaped from the stripes and the photoelectric conversion elements serve as pixels. The density of pixels can be increased higher than the density of photoelectric conversion elements.

[Embodiments of the invention]

An embodiment of the present invention will be described below. Note that the basic structure of the image sensor of the present invention is substantially the same as that of the prior art, so detailed explanation will be omitted.

FIG. 4 is a schematic plan view of a photoelectric conversion element in a photoelectric conversion section of an image sensor, viewed from the incident light side. In FIG. 4, strips (811), for example, are formed on opposing portions of the light receiving surface OI) consisting of a photoelectric conversion element. That is, between adjacent photoelectric conversion elements, thin pieces (al
The shape is such that one pixel G can be constructed by combining 1). The area of this strip (811) is one of the area of the light receiving surface c31). That is, the pixel F and the pixel G have light receiving surfaces of the same area. Generally, the electrical output of a photoelectric conversion element is proportional to the area of the light receiving surface of the photoelectric conversion element. Therefore, approximately the same electrical output corresponding to the pixel F and the pixel G will be obtained if the amount of light irradiated to the pixel F and the pixel G is equal. Therefore, according to one embodiment, the pixel density can be increased by 1.5 times (2 times) the photoelectric conversion element density. This simplifies wire bonding, etc., and improves manufacturing yield and reliability.

By the way, in the case of the image sensor shown in FIG. 4C-2, the electrical output corresponding to the pixel F is divided and outputted to the individual electrode (-) and the individual electrode (c). This signal processing method will be explained with reference to FIGS. 5 to 6(e). FIG. 5 is an explanatory diagram schematically showing the signal processing of the image sensor of one embodiment, and FIGS. It is an explanatory view shown typically. The electrical output (1) from each photoelectric conversion element is an electrical output obtained by sequentially reading electrical outputs from individual electrodes in a predetermined scanning time, similar to the conventional signal processing method. In one embodiment,
Since the pixel density is approximately 1.5 times higher than that of the photoelectric conversion element, the paired two-light conversion element (corresponding to individual electrodes (2) and (c) in Fig. 4) After the electrical output of , it is necessary to output a black level electrical output once as shown in FIG. That is, in order to convert the electrical output from the photoelectric conversion element into an electrical output corresponding to a pixel, it is necessary to increase the number of electrical output signals by 1.5 times.

Next, the sequentially read electrical outputs I are converted into digital signals by an analog-to-digital converter (51),
Electrical output 1. , I. The threshold value is the 6th
As shown in Figures (b) and (d), 1/8, 2/8, and 1 of the white level electrical output of the photoelectric conversion element are taken so as to be distinguishable. The electrical output converted into a digital signal is electrical output 1.2 corresponding to the first digit and electrical output 1.2 corresponding to the second digit. bawl. A switch converter (62) switches the electrical output I and the electrical output at a predetermined timing and outputs the electrical output.

The first 'electrical output of (2) is outputted as is (corresponding to the pixel), and I4 is outputted. The electrical output converted by the switch is temporarily stored in a memory device (58) as needed, and the timing of the electrical output is shifted. ■.

Of the electrical output of
The electrical output of x and the second electrical output of x are determined by the AND circuit (54) and the electrical output I (corresponding to the pixel)
, is output. Furthermore, the second electrical output (I,
is output simultaneously with the second electrical output of. ) is temporarily stored in the memory device (58) and becomes the electrical output I.

is outputted, and then outputted as an electrical output I6 corresponding to the pixel.

In the sixth factor, the arrow temporarily indicates the delay of the electrical output performed by the memory device (58) and the combined judgment of the electrical output by the AND circuit (54). Also, I is the electrical output ■4
+ "5 + engineering II, which is the electrical output corresponding to each pixel. The characteristics of this AND circuit (54) are shown in Table 1 below.

Table 1; AND circuit By using the above-mentioned signal processing method, the electrical output from the two photoelectric conversion elements that form a pair is converted into the 8
This enables conversion into electrical output corresponding to one pixel.

(The following is a margin) Table 2: Truth table Table 2 shows a truth table between pixels corresponding to digitally converted electrical outputs of paired photoelectric conversion elements. Note that each number shown on the matrix topsoil indicates the number of the pixel to be output, and the numbers shown in the terms Xi and X2 of the photoelectric conversion element indicate the magnitude of the electrical output. The signal processing method described above enables the pixel outputs shown in Table 2.

Next, another embodiment of the present invention will be described with reference to FIGS. 7(a) to 7(c).

In FIG. 7(,), a strip or interdigital electrode (812) extends from the light-receiving surface 01) of the opposing photoelectric conversion element. The light-receiving areas of the pixel G and the pixel F constituted by this interdigital electrode (812) are approximately equal.

In FIG. 7(b), each interdigital electrode (812) shown in FIG. 7(,) is individually combined,
A pixel G is formed therein.

In FIG. 7(c), strips (818) are extended from both ends of the light-receiving surface 01), and the strips (818) on both sides are combined to form pixels lit, G, and I. . The one shown in FIG.
, (64) is reduced, making it suitable for higher-density image sensors.

In addition, the strip (81B) is shown in Figure 7 (,) and Figure 7 (b).
Needless to say, it may be formed using interdigital electrodes as shown in FIG.

〔Effect of the invention〕

By adopting the above-described configuration, the image sensor of the present invention can increase the density of pixels relative to the density of photoelectric conversion elements. Furthermore, since individual electrodes are coupled one-to-one to each photoelectric conversion element, there is a side effect that the pixel density can be easily increased without changing the configuration of the drive circuit section.

[Brief explanation of drawings]

Fig. 1 is a schematic sectional view explaining the principle of an image reading device using an image sensor, Fig. 2 is a schematic sectional view showing the structure of a conventional image sensor, and Fig. 8 is a schematic sectional view showing the main parts of Fig. 2. FIG. 4 is a schematic plan view of a main part showing an embodiment of the image sensor of the present invention. FIG. 6 is a schematic diagram for explaining the belief method of an embodiment of the image sensor of the present invention. 6(,) to 6(e) are characteristic diagrams showing the characteristics of the electrical output in the signal processing method of FIG. 6, and FIG. FIG. 7 is a schematic plan view of main parts showing another embodiment. (9)...Image sensor Q...Output terminal @...Common electrode (goods), (c), (61), (62), (68
), (64)...Individual electrode (to)...Integrated circuit element 0...Light-receiving surface Agent Patent attorney Kensuke Chika (TL or 1 person) No.
1 Figure 0/ / Figure 2 α Fork θ β Figure 3 Figure 4 Figure 5 (C) ♂3 Figure 6

Claims (3)

[Claims] (1) Arranging a plurality of photoelectric conversion elements each consisting of an insulating substrate, a common electrode and a photoelectric conversion film formed on the insulating substrate, and individual electrodes electrically connected to the common electrode via the photoelectric conversion film. In the image sensor, the image sensor includes a photoelectric conversion section formed by a photoelectric conversion section and a drive circuit section electrically connected to the photoelectric conversion section and formed on the insulating substrate, in which stripes extend from opposing photoelectric conversion elements. An image senna characterized by: (2) The image sensor according to claim 1, wherein the strip has a plurality of blind-like shapes. (3) The image sensor according to claim 1, wherein the strip is composed of a single strip.