JPH0758767B2 - Perfect contact image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a perfect contact image sensor for reading an image at an actual size, in particular, a rod lens for image formation is omitted to integrate a light source and a light receiving element. The present invention relates to a perfect contact image sensor.

(Prior Art) Conventionally, as a technology of such a field, Nikkei Menical (1986-12-1) Nikkei McGraw-Hill, Inc. "For trump card of miniaturization of contact type image sensor OA equipment with short optical path" P.71-78 Some were mentioned. The configuration will be described below with reference to the drawings.

FIG. 2 is a diagram showing a configuration example of a conventional contact image sensor.

This contact image sensor is composed of a light emitting diode (hereinafter referred to as LED) array 2 for irradiating a document 1, a rod lens array 3 for image formation, and a light receiving element 4 for optical / electrical conversion. . When the document 1 is irradiated with the light emitted from the LED array 2, the image of the document 1 is formed on the light receiving element 4 through the rod lens array 3, converted into an electric signal by the light receiving element 4, and read.

In this type of contact image sensor, since the image of the original 1 is read at the original size using the rod lens array 3, the optical path is significantly shortened as compared with an image sensor using a reduction optical system, and a copier or facsimile machine is used. It is possible to reduce the size of the image reading device such as.

However, since the rod lens array 3 is used, it is not sufficiently satisfactory in terms of size and weight reduction. Therefore, a perfect contact type image sensor without the rod lens array 3 has been proposed.

FIG. 3 is a diagram showing a configuration example of a conventional perfect contact image sensor.

The perfect contact type image sensor includes an LED array 10 and a sensor body 20. The sensor body 20 has a glass substrate 21, the electrode 22, on the bottom surface of the glass substrate 21,
A light receiving element 23 made of amorphous silicon (hereinafter referred to as a-Si), a transparent electrode 24, and an electrode 25 are formed in a laminated state. A window 26 for passing light is provided in the center of the light receiving elements 23 and the like, and these light receiving elements 23 and the like are covered by a transparent protective layer 27.
Is covered with. An original 28 is placed under the transparent protective layer 27. Then, by the LED array 10, the glass substrate 2
1. When a document 28 is illuminated through the window 26 and the transparent protective layer 27, the image of the document 28 passes through the transparent protective layer 27 and the light receiving element.
It is converted into an electric signal at 23.

In this perfect contact type image sensor, since the rod lens array is omitted, the size and weight can be reduced, and there is no light amount loss in the rod lens array.
The output of 23 also becomes large and the signal-to-noise ratio (S / N ratio) improves.

(Problems to be solved by the invention) However, in the perfect contact type image sensor of FIG. 3, since the LED array 10 as a light source and the sensor body 20 on the light receiving element 23 side are individually configured, the size is small. However, there was a limit to weight reduction. Moreover, when assembling the image sensor as a unit, it is necessary to adjust the mounting positions of the LED array 10 and the sensor body 20, and the adjustment is complicated, and if the adjustment is insufficient, Since the amount of incident light is reduced and the reading accuracy is lowered, it is difficult to solve them.

The present invention provides a complete contact type image sensor that solves the problems of the above-mentioned conventional technology in that there is a limit to the reduction in size and weight and the complexity of adjusting the mounting position between the light source and the sensor body. To do.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a perfect contact type image sensor which irradiates light to electrically read an image at a full scale, in which at least the image sensor is mounted on an element. Substrate, a light-receiving element formed on the substrate, a hole formed in a predetermined region in the light-receiving element, a light-emitting element formed in the hole, and the light-receiving element and the light-emitting element deposited on the substrate. And a translucent protective film.

(Operation) According to the present invention, since the complete contact type image sensor is configured as described above, the light emitting element and the light receiving element formed on the same substrate serve to improve the size and weight reduction by integration. . Further, the hole in which the light emitting element is formed serves to enable the positional relationship between the light emitting element and the light receiving element to be set with high precision in the stage of the manufacturing process, and to eliminate the need for position adjustment during assembly work. Therefore,
The above problems can be eliminated.

(Embodiment) FIGS. 1 (1) and 1 (2) show an embodiment of the present invention. FIG. 1 (1) is a schematic plan view of one dot of a perfect contact image sensor, and FIG. 2) is a sectional view taken along the line AA.

This perfect contact image sensor is a glass plate, resin plate,
There is an insulative substrate 30 such as a metal plate that is insulation-coated, and a common electrode 31 made of chromium or the like is formed on the substrate 30. When the substrate 30 is made of a translucent material, the common electrode 31 is made of a non-translucent light shielding material. On the common electrode 31, a film-shaped light receiving element 32 made of hydrogenated amorphous silicon (a-Si: H) for converting light into electricity is formed by plasma CVD (chemical vapor deposition), electron cyclotron, or the like. Resonance (ECR) CVD, optical CV
D, sputter, etc. On the light receiving element 32,
A light-transmitting light-receiving element individual electrode 33 made of indium tin oxide (ITO) or the like is formed by sputtering or the like. The laminated structure of these common electrode (metal) 31 / light receiving element (semiconductor) 32 / individual electrode (metal) 33 exhibits a light receiving element function.

A hole 34 for forming a light emitting element is formed by etching or the like in the individual electrode 33 and the light receiving element 32 at a location located at the center of the light receiving element 32, for example. A translucent insulating film 34 made of polyimide resin or the like is deposited on the light receiving element 32 and the separate electrode 33 by plasma CVD, sputtering or the like, and a light emitting element 35 is formed in the hole 34 through the insulating film 34. Has been done. Light emitting element
The numeral 35 is for converting electricity into light, and is made of zinc sulfide / manganese (ZnS: Mn) or the like, and is formed by vapor deposition, sputtering, or the like, on which an insulating film 36 is selectively deposited. There is. With the structure in which the light emitting element 35 is sandwiched by these insulating films 33 and 36, the function as a light emitting element is exhibited. For example, when ZnS: Mn is used as the light emitting material, since the wavelength of the emission peak in the light emitted by ZnS: Mn is in the visible region,
It is suitable that the sensitivity of, for example, a-Si: H forming the light receiving element 32 has a peak in the visible light region. The insulating film 34 has a function of electrically insulating the light receiving element 32 and the light emitting element 35 from each other, and when a ZnS: Mn system is used as the light emitting element material, the light emitting element (that is, an electroluminescence (EL) element). )
It functions as an insulating film of itself.

On the insulating films 34 and 36, a light-transmissive individual electrode 37 for a light emitting element made of ITO or the like is formed by vapor deposition, sputtering or the like. On the light emitting element 32, the light emitting element 35, the individual electrode 37, etc., a translucent insulating protective film 38 made of a polyimide resin or the like for protecting them is adhered and faces the protective film 38. Document 39 is set.

Next, the operation will be described.

First, the common electrode 31 is connected to the ground so as to be used for both the light receiving element 32 and the light emitting element 35, and a negative voltage is applied to the light receiving element individual electrode 33 and a positive voltage is applied to the light emitting element individual electrode 37. Apply. Then, the light emitting element 35 emits light, and the emitted light is the insulating film 36, as shown by the arrow in FIG.
The original 39 is irradiated through the individual electrode 37 and the protective film 38. The image of the original 39 is converted into an electric signal by the light receiving element 32 through the protective film 38, the individual electrode 37 and the insulating film 34, and is read.

The present embodiment has the following advantages.

(A) A light receiving element 32 is formed on the substrate 30 and the light receiving element is formed.
Since the light emitting elements 36 are formed in the holes 34 of 32 and they are integrated, the size and weight of the entire sensor unit can be remarkably improved.

(B) Since the light receiving element 32 and the light emitting element 35 are formed on the same substrate 30, the light receiving element 32 is formed during the manufacturing process.
Thus, the light emitting element 36 can be accurately formed at an accurate arrangement position.
Therefore, it is possible to omit the complicated work of position adjustment at the time of assembling work of the light source and the light receiving element as in the prior art, simplify the manufacturing process, and improve the optical axis matching accuracy.
The reliability can be increased.

(C) Since the distance between the light emitting element 35 and the document 39 becomes short,
Incident light on the original 39 becomes stronger and the S / N ratio is significantly improved. In addition, since the light emitting element 35 is formed in the hole 34 of the light receiving element 32 via the insulating film 34, the light quantity loss is small, the light emission efficiency is high, and the low power consumption can be expected.

(D) Since the common electrode 31 is also used as the light receiving element 32 and the light emitting element 35, the number of electrodes can be reduced.

The present invention is not limited to the illustrated embodiment, and various modifications can be made. The following are examples of such modifications.

(I) The light receiving element 32 and the light emitting element 35 can be formed of various materials other than those shown in the drawings.

For example, FIG. 4 is a sectional view of the light emitting element portion in FIG. 1 (2). As shown in FIG.
May be formed by a three-layer pin junction made of amorphous silicon carbide (a-Sic) or an nip junction. In this case, after forming the insulating film 34,
If the insulating film 34 in the lower part of the hole 34 is etched to expose a part of the common electrode 31, the light emitting element 35A is formed thereon by plasma CVD, sputtering, etc., and further the individual electrode 37 is formed thereon. Good. Since a-Sic has a light emission peak wavelength in the visible light region, it is suitable that the sensitivity of a-Si: H as a light receiving material has a peak in the visible light region.

(Ii) The common electrode 31 and the individual electrodes 33 and 37 are the light receiving elements 32.
Also, the light emitting element 35 can be deformed into various arrangements and shapes according to changes in the arrangement state, shape, and the like.

(Effects of the Invention) As described in detail above, according to the present invention, the light receiving element is formed on the substrate, and the light emitting element is formed inside the hole of the light receiving element. The weight saving can be remarkably improved, and the light emitting element and the light receiving element can be accurately formed at appropriate arrangement positions, thereby simplifying the manufacturing process and improving reliability. Since the distance between the light emitting element and the original is shortened, the S / N ratio is remarkably improved. Moreover, since the light emitting element is formed in the hole of the light receiving element, high emission efficiency and low power consumption can be expected. . Furthermore, since the common electrode is also used as the light emitting element and the light receiving element, the effect of reducing the number of electrodes can be expected.

[Brief description of drawings]

1 (1) and 1 (2) show an embodiment of the present invention.
FIG. 1A is a schematic plan view of the perfect contact image sensor, FIG. 2B is a sectional view taken along the line AA of FIG. 1A, and FIG. 2 is a configuration diagram of a conventional contact image sensor. FIG. 3 is a configuration diagram of a conventional perfect contact type image sensor, and FIG. 4 is a cross-sectional view of the light emitting element portion of FIG. 1 (2). 30: substrate, 31: common electrode, 32: light receiving element, 33, 37
...... Individual electrodes, 34 …… Hole, 35,35A …… Light emitting element, 38 ……
Protective film, 39 ... manuscript.

Claims (1)

[Claims] 1. A perfect contact image sensor for irradiating light to electrically read an image at a full scale, in which a substrate for mounting an element and a light-receiving element for optical / electrical conversion formed on the substrate, A hole formed in a predetermined region in the light receiving element, a light emitting element for electrical / optical conversion formed in the hole, and a light transmitting protective film deposited on the light receiving element and the light emitting element. , A complete contact image sensor.