JPS6141268A - Close adhesion type image sensor - Google Patents

Abstract

PURPOSE:To keep a constant distance between the surface of an original and a photoelectric conversion element and also to prevent the deterioration of picture quality due to the an injury or stain produced by the friction between the original and a transparent protection film, by putting said protection film replaceably and movably between the original and the photoelectric conversion element. CONSTITUTION:A light shielding film 4 which is optically opaque and insulated electrically is provided on a transparent substrate 3 of glass, etc. excluding the part of a transparent window 19 together with a photoelectric conversion element 5 and an electrode 6 and a transparent electrode 7 set at both ends of the substrate 3 respectively. Furthermore a transparent protection film 2 is put between an original 1 and the element 5. The film 2 uses a comparatively hard material such as polyimide, polycarbonate, transparent acrylic material, etc. The thickness of the film 2 is properly decided from the luminous intensity, the image resolution, etc. A luminous flux 8 given from a light source is irradiated to the original 1 through the window 19 and this reflected light is caught by the element 5. The film 2 and the substrate 3 are separate from each other. Thus the film 2 is injured or soiled can be replaced with another nondefective one or can be shifted. In such a way, the high picture quality is secured again.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a contact type image sensor that is used in a reading system for facsimiles, document files, etc., and performs reading in close contact with a document.

[Conventional technology]

Conventionally, several types of contact image sensors have been proposed for the purpose of downsizing devices such as factor j IJ. For example, although not shown, there is a method that uses a light-condensing optical fiber array to form an erect, same-size image of a document on an image sensor, and a transparent protection method for a contact type image sensor as shown in Figure 2. For example, the layer 9 and the original 1 are brought into contact with each other, the transparent substrate 3 is illuminated from below, the reflected light is captured by a photoelectric conversion element, and the light is converted into 'IIj'. For example, various methods of illuminating a transparent substrate from below are disclosed in Japanese Patent Application Laid-open Nos. 55-74262, 1982-27562, and 58-127463.

[Problems to be Solved by the Invention] However, each of the conventional contact type image sensors has its own drawbacks. In the method using a condensing fiber array, the condensing fiber array is expensive and the focus adjustment is complicated, and in the case of the method 1 and 7 shown in FIG. 2, the original 1 and the transparent protective layer 9 are rubbed. Therefore, scratches and stains occur on the transparent protective layer 9, which significantly reduces reliability and has not been put to practical use. In addition, since no lens system is used, the illuminance of the original 1
Due to the resolution related to the degree of integration of the photoelectric conversion elements, the distance between the original 1 and the photoelectric conversion element 5 is 100 μm or less, and it is difficult to maintain this distance without contact. Also, transparent protective layer 9
To form this, there are methods such as sputtering of glass, transparent resin, and coating of thin glass, but the thickness of the transparent protective layer is as thick as 30 to 80 μm, and it is difficult to form it using thin layer technology. When coating a transparent resin, it is difficult to obtain a uniform film thickness, and there are problems such as high resistance to thin glass.

Therefore, in order to solve these conventional drawbacks, the present invention aims to provide an inexpensive contact type image sensor that can be used even if the part that contacts the original is dirty or scratched. Means for Solving the Problems] In order to solve the above-mentioned problems, this invention was developed.Since it is difficult to prevent stains and scratches from occurring as long as there is friction, the portion corresponding to the conventional transparent protective film is constructed as a transparent protective film. The structure allows for replacement or movement without being integrally formed with the transparent substrate.

r effect] When a document is read with the contact type image sensor configured as described above, the distance between the surface of the document and the photoelectric conversion element is determined by the thickness of the transparent protective film, and is uniformly distributed over the entire area of the contact type image sensor. Because there is friction between the fc original and the transparent protective film, scratches and dirt will eventually occur, but
Reliability can be maintained by replacing or moving the transparent protective film.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, a light-shielding film 4 made of an optically opaque and electrically insulating material, such as silicon germanium, is provided on a transparent substrate 3 such as glass, except for a transparent window 190, and a CDS.

The process is exactly the same as the conventional technology until a photoelectric conversion element 5 made of CD SE or amorphous silicon is provided, and an electrode 6 made of chromium, gold, etc. and a transparent electrode 7 made of tin oxide, indium oxide, etc. are provided from both ends. Can be configured. Two transparent protective films are interposed between the original 1 and the photoelectric conversion element 5.

Transparent film J-2 is preferably made of a relatively hard material such as polyimide or polycarbonate, and for some, transparent acrylic, and the individual chooses the optimal thickness based on illuminance and resolution. For example, in the case of a photoelectric conversion element 5 with 98 dots per dragon, the diameter is 70 μm.
Films in the vicinity are suitable and can be produced at low cost.

Since the transparent protective film 2 and the transparent substrate 3 are not integrally formed, if the transparent protective film 2 becomes scratched or dirty, it can be replaced or moved to obtain good image quality again. . The embodiment shown in FIG. 1 shows a cross-sectional view of a contact type image sensor of the present invention, in which five photoelectric conversion elements are arranged in an array in the direction perpendicular to the plane of the paper, as in the conventional case. Figure 8d 'This is a luminous flux from a light source such as an LED or a fluorescent light (not shown), which illuminates the document 1 through the transparent window 19, and shows how the reflected light is captured by the photoelectric conversion element 5.

FIG. 3 is a 7'l sectional view of an embodiment in which the transparent protective film 2 is configured to be replaceable. The transparent protective film 2 is placed on a support base 10 and fixed with fixing members 11 such as screws and springs. . If scratches or stains occur in the area where the document 1 and the transparent protective film 2 rub against each other, the transparent protective film 2 can be replaced to prevent sexually transmitted diseases again. Although not shown, in order to maintain the distance between the original 1 and the photoelectric conversion element 5, it is preferable to use a structure in which the original is lightly pressed with a rubber roller.

FIG. 4 is a sectional view of an embodiment in which the transparent protective film is configured to be movable.The transparent protective film 2 is wound around the winding section 12 and is fed manually or automatically, so that it is always protected against scratches. It can be laid down in a clean and clean condition. If the structure is movable, there is no need to limit it to the winding method. With this configuration, the transparent protective film 2 can be attached and detached as a cartridge. The mechanism for moving the transparent protective film 2 is the winding section 12 using a steno knob motor.
This can be achieved using known techniques such as rotating or feeding with rubber rollers.

FIG. 5 is a sectional view of an embodiment in which an illumination window 14 is provided on a transparent protective film. A document light-shielding film 13 is provided on the transparent protective film except for the illumination window 14 using an optically opaque material such as paint or metal. This limits the illumination area of the original, thereby limiting the light flux that enters the photoelectric conversion element 5, thereby improving resolution.

Figure 6 shows film protection 1 [15] on transparent protection film 2.
FIG. Film protective film 15 A highly hard thin film made of aluminum oxide or silicon nitride, which can be formed by sputtering or the like. This makes it possible to extend the life of the transparent protective film 2.

FIG. 7 is a detailed diagram of an example in which hydrogenated amorphous silicon is used as the material of the photoelectric conversion element 5. Hydrogenated amorphous silicon has good spectral sensitivity characteristics, fast optical response speed, and large size. It is a material that can be decomposed using glow discharge decomposition methods. In the case of this embodiment, the transparent electrode 7 and the electrode 6 made of chromium or the like are used to generate light! Although an example is shown in which the conversion element 5 has a sandwich structure, it may also have a PIN structure or the like.

FIG. 8 is a sectional view of an embodiment in which a transparent protective film is provided on a photoelectric conversion element. The transparent protective film 16 may be similar to the surface protective film of a normal integrated circuit, and may be silicon 9ide or silicon phosphate. In this case, it is not necessary to make the surface protective film 16 thicker, and it is sufficient to withstand the friction of the transparent protective film 2.

FIG. 9 is a sectional view of an embodiment in which a transparent insulating film 17 is provided on the light shielding film 4. When the light shielding film 4 is made of an electrical conductor such as metal, it is necessary to insulate the electrode 6 or the transparent electrode 7 from the light shielding film 4. For this purpose, a silicon nitride film or a silicon oxide thin film is used as the transparent insulating film 17. You can set it as .

FIG. 10 is a sectional view of an embodiment in which a transparent lubricant is interposed between the transparent protective film 2 and the photoelectric conversion element 5. The transparent lubricant 18 is, for example, silicone oil, and has the function of suppressing scratches caused by friction between the transparent protection film 2 and the optical N conversion element 5 and moving dust particles to the surrounding area.

In the embodiments described above, there are various methods for pressing the document, such as pressing with a rubber roller and pressing with a spring. If the thickness of the transparent protective film 2 is uniform, the distance between the original s1 and the photoelectric conversion element 5 will be constant, and therefore variations in resolution will be reduced. Also, although the transparent protective film and the photoelectric conversion element side come into contact, the frequency of friction is low;
No need to worry about scratches or dirt. Similar to integrated circuits, a transparent protective film is provided on the photoelectric conversion element side to ensure reliability, but there is no need to make it extremely thick as in the past.

〔Effect of the invention〕

As explained above, this invention has an extremely simple structure in which a transparent protective film is interposed between the original and the light conversion element in a replaceable and movable state, and there is little variation in resolution, resulting in poor image quality due to scratches and dirt. It is possible to avoid a decrease in

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a contact type image sensor according to the present invention, and FIG. 2 is an n-plane view of a conventional contact type image sensor. 3 to 10 are cross-sectional views showing embodiments of various parts of the contact type image sensor b according to the present invention. 1. Original 2. Transparent protective film 3.
Transparent substrate 5... Optical IKK conversion element 10... Support stand 11... Fixing member 12... Winding section
13... Original light-shielding film 14... Lighting window 15...
Film protective film 16...Transparent protection@17...Transparent insulating film 18...Transparent lubricant Above, Ganto Ueda
Seiko Electronics Industries Co., Ltd. Figure 1! ,! Draft No. 3 Ey, j Figure 5

Claims (9)

[Claims] (1) photoelectric conversion elements arranged on a transparent substrate are brought into close contact with a document, and illuminated from the direction opposite to the document side of the transparent substrate;
In image sensors that capture reflected light and convert it into electricity,
A contact type image sensor characterized in that a transparent protective film is interposed between a photoelectric conversion element and a document without being formed integrally with the transparent substrate. (2) The contact type image sensor according to claim 1, wherein the transparent protective film is configured to be replaceable using a support stand and a fixing member. (3) Claim 1, characterized in that the transparent protective film is movable relative to the photoelectric conversion element.
Close-contact image sensor as described in . (4) The contact type image sensor according to claim 1, wherein the transparent protective film is provided with an original light-shielding film and an illumination window for limiting the illumination area of the original. (5) The contact type image sensor according to claim 1, wherein a film protective film is provided on the side of the transparent protective film that comes into contact with the original. (6) The contact image sensor according to claim 1, wherein the photoelectric conversion element is made of hydrogenated amorphous silicon. (7) The contact type image sensor according to claim 1, wherein a transparent protective film is provided on the photoelectric conversion element. (8) A contact image sensor according to claim 1, characterized in that a light-shielding film made of metal and a transparent insulating film are provided on a transparent substrate, and a photoelectric conversion element is provided thereon. (9) The contact type image sensor according to claim 1, wherein a transparent lubricant is interposed between the transparent protective film and the photoelectric conversion element to reduce friction.