JPS5923436Y2 - Photoelectric conversion device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a charging conversion device whose size corresponds 1:1 to a document used in a reading system of a facsimile machine or the like.

Conventionally, in a reading system for a transmission document such as a facsimile machine, as shown in FIG. They formed an image to obtain time-series electrical signals.

In this case, since the charging conversion device 4 has a chip size of about 20 mm manufactured by IC technology such as MOS or CCD, the transmission document 1 is A 4 (= 20 mm).
0 mm x 290 mm), the reduction ratio of the lens is about 1/10, and the distance from the transmission document 1 to the photoelectric conversion device 4 is
The distance to the center is quite long, which has the disadvantage of making the device large.

In order to solve this drawback, a large-sized charging conversion device that corresponds to the transmission original 1 on a 1:1 basis has been proposed.

This photoelectric conversion device has a transparent substrate 5 as shown in FIG.
A row of light-receiving elements 6 is formed on the top by vapor deposition or photoresist technology, and a transparent protective layer 7 is provided on top of the array.

A light beam 8 from an illumination light source (not shown) placed below the transparent substrate 5 passes through the transparent substrate 5, the gap between the light-receiving elements 6, and the transparent protective layer 7, and illuminates the transmission original 1, and the reflected light is captured by the light-receiving element 6 and photoelectrically converted. However, the transparent protective layer 7 needs to have a certain thickness from the viewpoint of strength and stability against friction with the transmission document 1, or from the point of view of efficiently introducing the illumination light flux. It is.

For this reason, due to the thickness of the transmission document 1 to the light receiving element 6, it is impossible to achieve sufficient contact, and the transparent protective layer 7 becomes a kind of light guide path, and the reflected light is diffused and transmitted to reach the adjacent light receiving element 6. However, it had the disadvantage of lower resolution.

In order to eliminate the above-mentioned drawbacks, this invention provides a light guiding layer whose refractive index distribution changes in the thickness direction between the light receiving element and the transmission document.

This idea will be explained in detail below.

FIG. 3 is a partial front cross-sectional view in the main scanning direction showing an embodiment of this invention. be.

In Fig. 3, 1 is a transmission original, 5 is a transparent substrate such as a glass plate,
6 is a light receiving element such as CdS or Se, 7 is a transparent protective layer,
8 is an illumination light flux, and 9 is a light guide layer having a refractive index distribution, which is composed of a transparent high refractive index layer 10 and a transparent or opaque low refractive index layer 11.

During manufacturing, a row of light-receiving elements 6 is formed on a transparent substrate 5 by vapor deposition and photoresist technology, the row of light-receiving elements 6 is further covered with a transparent protective layer 7, and a light-guiding layer 9 is placed on top of the transparent protective layer 7. The index layer 10 is formed so that each light receiving element 6 faces each other.

In addition, in FIG. 3, the electrodes and wiring of each light receiving element 6 are omitted.

FIG. 4 is a partially enlarged sectional view for explaining the operation of the above embodiment.

The operation will be explained below.

The illumination light flux 8 is a part of the light flux emitted from an illumination light source (not shown), and illuminates the transmission document 1 through the transparent substrate 5, the gap between the light receiving elements 6, the transparent protective layer 7, and the light guide layer 9. .

The reflected light from the illuminated transmission document 1 is diffusely radiated from the transmission document 1 in all directions, but most of it is captured by the nearest light receiving element 6 and photoelectrically converted.

Of the diffusely emitted light fluxes, the light fluxes with large reflection angles propagate through the high refractive index layer 10 of the light guide layer 9 and head towards the adjacent light receiving element 6, but are totally reflected by the low refractive index layer 11 in the middle, and are reflected by the main body. is captured by the light receiving element 6.

Therefore, the interference light leaking to the adjacent light receiving element 6 becomes extremely small, and high resolution is ensured.

In the above case, the light guide layer 9 can be manufactured all at once into one plastic sheet by, for example, photopolymerization of a plastic material.

In this embodiment, the reflected light from the transmission document 1 is efficiently totally reflected by the low refractive index layer 11, so that even higher resolution can be expected.

Note that the low refractive index layer 11 for preventing diffusion is also provided in the sub-scanning direction (direction perpendicular to the direction in which the light-receiving elements are arranged), but the contribution to resolution in the main-scanning direction (the direction in which the light-receiving elements are arranged) is Since is considered to be small, this can be omitted.

Further, in each of the above embodiments, the light guide layer 9 and the transparent protective layer 7 are configured separately, but the light guide layer 9 itself may also serve as the transparent protective layer 7, and in that case, the configuration becomes simpler. .

As explained above, in this invention, a light guide layer with a refractive index distribution in which the width of the low refractive index layer changes in the thickness direction is provided between the transmission document and the light receiving element, so that the light flux leaks to the adjacent light receiving element. can be prevented, and a decrease in resolution can be eliminated.

Furthermore, it has the advantage that the facsimile machine used can be made smaller and simpler.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a conventional transmission document reading system such as a facsimile machine, and Fig. 2 is a partial sectional view of a conventional charging conversion device.
FIGS. 3 and 4 are a partial front sectional view and an enlarged view of a charging conversion device showing an embodiment of this invention. In the figure, 1 is a transmission original, 5 is a transparent substrate, 6 is a light receiving element, and 7
8 is a transparent protective film, 8 is an illumination light flux, 9 is a light guide layer, 10 is a high refractive index layer, and 11 is a low refractive index layer.

Claims (1)

[Scope of utility model registration request] A transparent protective layer for protecting these light receiving elements is formed on top of the row of light receiving elements formed on a transparent substrate, and a low refractive index layer is arranged on top of this transparent protective layer so as to surround each of the light receiving elements. A light guide layer with a refractive index distribution is provided, and the rest is a high refractive index layer, and the original is illuminated through the transparent substrate from an illumination light source installed at the bottom of the transparent substrate, and the reflected light is guided to the light receiving element for photoelectric conversion. A charge conversion device characterized in that the low refractive index layer becomes gradually thinner from the upper surface in the thickness direction of the light guide layer.