JPH02271225A - Color sensing element and group of the same - Google Patents

Abstract

PURPOSE:To simplify the structure of an instrument by laminating two or more amorphous semiconductor layers with different thicknesses on a first common electrode coated on an insulating substrate and providing each of the layers with a second electrode. CONSTITUTION:An amorphous silicon carbide p-layer 16 is coated on a transparent electrode 12 as an amorphous semiconductor layer 14 and a i-layer 18 is coated on the p-layer 16. Then, the i-layer 18 is removed to a given layer thickness except one-third portion 18a and only the one-third portion is removed to a given layer thickness by the technique of photolithography. Therefore, the i-layer 18 is composed of portions 18a - 18c with different thicknesses. When light is incident on a color sensing element 26, the wavelengths of three primary colors: i.e. red, green and blue composing light act on the i-layers 18a - 18c, respectively, to generate photocurrent and electric charge quantities according to the intensity of each spectral component. By relatively comparing the values of the photocurruent and electric charge quantity generated in the three photoelectrically converting sections 18a - 18c with one another and performing computations, colors can be discriminated from one another.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a color sensor element and a group of color sensor elements having color resolution.

[Prior art] Light reflected and transmitted from an object is composed of three primary colors: red, blue, and green, and a color sensor that distinguishes colors distinguishes between red, blue, and green.
It is configured to separate the three primary color components of green and detect each component. Conventionally, two types of detection methods have been proposed. One of them is a color sensor disclosed in Japanese Patent Application Laid-Open No. 58-125868. This color sensor consists of three types of elements, each consisting of a red, blue, and green color filter film fixed on an amorphous semiconductor element. It is designed to detect the decomposed spectra.

The other one is a color sensor disclosed in Japanese Patent Application Laid-open Nos. 61-283838 and 63-94125.

This color sensor takes advantage of the fact that the peak wavelength of the spectral sensitivity characteristic of amorphous semiconductors changes depending on the bias voltage, and applies three different bias voltages to the element to obtain the peak wavelengths of red, blue, and green. It is.

[Problems to be Solved by the Invention] A color sensor using color filter films requires a process of fixing three types of color filter films. Moreover, there is a problem that the color of the color filter film changes or fades over time, deteriorating its ability to separate light into three primary color components, and furthermore, there is a problem that the color filter film peels off before it deteriorates. there were.

On the other hand, color sensors that use bias voltages do not have the above-mentioned problems, but they have the problem that three types of bias voltages must be applied to each element, making the device complex, expensive, and expensive.

As a result of intensive research to solve the problems of these conventional techniques, the present inventors obtained an idea different from the above-mentioned conventional techniques and arrived at the present invention.

[Means for Solving the Problems] The gist of the color sensor element according to the present invention is that a first common electrode is deposited on an insulating substrate, and at least two or more electrodes are provided on the first common electrode. Preferably, the method includes three amorphous semiconductor layers laminated with different thicknesses, and a second electrode deposited on each of the amorphous semiconductor layers with different thicknesses. be.

Further, the amorphous semiconductor layer of the color sensor element according to the present invention is made of silicon or silicon-based material, and has at least an i-type amorphous semiconductor layer, and has at least an i-type amorphous semiconductor layer. The reason is that the film thickness is different.

In particular, the amorphous semiconductor layer of the color sensor element is made of silicon or silicon-based material, and the amorphous semiconductor layer has a pi-type or ni-type structure, and the i-type amorphous The reason is that the thickness of the quality semiconductor layer is varied in the range of 1,000 to 30,000 layers.

Furthermore, the insulating board of the color sensor element is a translucent substrate,
The first common electrode is a transparent electrode made of a transparent conductive film.

Further, the color sensor element group according to the present invention is constructed by arranging a large number of the color sensor elements in a plane.

[Function] According to the present invention, the amorphous semiconductor layers of the color sensor element, particularly the i-layers, are laminated in at least two or more, preferably three, different thicknesses. Since the sensitivity peaks of the spectral sensitivity characteristics of amorphous semiconductor layers with different film thicknesses are different, the photocurrent generated in a sensor element equipped with two or more types of amorphous semiconductor layers with different film thicknesses,
By relatively comparing and reading the amount of charge, it is possible to identify the color corresponding to the sensitivity peak.

In particular, a color sensor element can be constructed by setting the thickness of the amorphous semiconductor layer in three types so as to exhibit peak sensitivity at the wavelengths of red, blue, and green, which are the three primary colors of light. The amorphous semiconductor layer having different sensitivity peaks separates the light received by the color sensor element into three primary colors to generate a photocurrent and an amount of charge. The color of the light incident on the color sensor element is determined by comparing the respective photocurrents generated in the 3fl type amorphous semiconductor layers.

Further, by configuring a color sensor element group in which a large number of color sensor elements are arranged in a plane, a color image sensor can be obtained that identifies the colored pattern of an object in a plane.

[Example] Next, an example of the present invention will be described in detail based on the drawings. Note that the drawings are shown enlarged as appropriate for the purpose of explanation.

In FIGS. 1(a), (b), and (c), reference numeral 10 is an insulating substrate, and the insulating substrate 10 is an insulating light-transmitting substrate such as glass, a polymer film, a polymer sheet, or a metal sheet. 5. The insulating substrate 10 is composed of an insulating opaque substrate such as a metal foil with an insulating film applied to the surface or a ceramic, and as the insulating substrate 10, a flexible substrate may be used in addition to a rigid substrate. Here, for the sake of explanation, a light-transmitting substrate will be used as the insulating substrate 10.

A transparent electrode 12, which is a first common electrode, is deposited on the light-transmitting temporary electrode 10 by sputtering or the like. transparent 7
! ITO, Snow, ITO/5n02 for l pole 12
It is formed into a predetermined pattern by a photoetching method, a mask method, a laser scribing method, or the like. The transparent electrode 12 is formed so as to serve as a common electrode for a plurality of photoelectric conversion areas formed on the transparent substrate 10.

An amorphous semiconductor layer 14 is deposited on the transparent electrode 12 by an ion blasting method, a vacuum evaporation method, a plasma CVD method, a sputtering method, or the like. The amorphous semiconductor layer 14 is made of, for example, amorphous silicon a-5i,
Hydrogenated amorphous silicon a-S i : l(,
Hydrogenated amorphous silicon carbide a-3jC=)
In addition to those made of amorphous materials such as l+ amorphous silicon nitride, there are also amorphous silicon-based semiconductor layers that contain microcrystals and are made of alloys of silicon Si and other elements such as carbon C, germanium Ge, and tin Sn, and - V
Group semiconductors, II-Vl group semiconductors, etc. are used. Particularly preferred is an amorphous silicon semiconductor layer,
An example in which an amorphous silicon-based semiconductor layer is used as the amorphous semiconductor layer 14 will be described.

First, two layers 16 of amorphous silicon carbide are deposited as the amorphous semiconductor layer 14 on the transparent electrode 12, and one layer 18 is further deposited on the two layers 16 within a range of approximately 30,000 people. It will be done.

Next, by photolithography, the deposited layer 18 is removed to a predetermined thickness except for about one-third part 18a, and further, only about one-third part 18c is coated with a predetermined film. The thickness is removed.

Therefore, i N I 8 deposited on pH 16 is composed of portions 18a, 18b, and 18c having different thicknesses. Here, it is recognized that there is a relationship between the film thickness of the amorphous semiconductor layer 14, particularly the single layer 18, and the wavelength of light that provides the sensitivity peak, such that as the film thickness increases, the wavelength that provides the sensitivity peak becomes longer. So, irr! j18
The film thicknesses of a, 18b, and 38C are determined and set in advance through experiments, for example, values that give a sensitivity peak based on the spectrum of red, green, and blue, which are the three primary colors of light.

Since each portion 1.8a, 18b, and 18c of the amorphous semiconductor layer 14 formed to have a different thickness is used as a photoelectric conversion area, no leakage current flows between adjacent photoelectric conversion areas. One layer 18a, 1 of the amorphous semiconductor layer 14 divided into six parts by a laser scribing method etc.
On each of 8b and 18c is a second electrode 20.22.
．． 24 is applied. The second electric i20.22.24 is aluminum containing 5% aluminum, chromium.

Applying nickel or the like by vapor deposition or sputtering, or screen printing a conductive paste obtained by kneading metal powder, carbon powder, etc. with resin or conductive polymer such as epoxy or phenol, or It is applied and formed into a predetermined shape.

When light enters the color sensor element 26 formed in this manner, the wavelengths of the three primary colors of the light, red, green, and blue, each give a sensitivity peak. a, 1
8b and 18c to generate a photocurrent and an amount of charge, respectively, depending on the intensity of each spectral component. Therefore, the three photoelectric conversion areas (18a, 18b, 1
By relatively comparing and calculating the values of the photocurrent and charge amount generated in step 8c), the wavelength, that is, the color of the incident light can be determined.

Here, the symbols 28, 30, 32 .
34 are extraction electrode portions for extracting photocurrent.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments.

For example, the first common electrode (12) is connected to each photoelectric conversion area (
18a, 18b, 18c) is used as a common electrode for temperature compensation, etc., and as long as the electrodes are connected, they do not necessarily need to have an integral structure.

Further, the amorphous semiconductor layer 14 is not limited to the above-mentioned pi type;
Of course, it may be of a layered type. These pi
type and n-layer type are the easiest structures to manufacture when manufacturing color sensor elements, but other structures such as pin type, two-layer including at least i-layer, and n-layer composite type may also be used. The film thicknesses of the P layer and the n layer may also be changed depending on the conditions.

The thickness of the amorphous semiconductor layer 14 can be changed by sequentially etching the amorphous semiconductor layer deposited by photolithography, or by sequentially etching the amorphous semiconductor layer deposited by sequentially moving a mask using a mask method. The thickness of the semiconductor layer may be increased.

Furthermore, it is most preferable to configure the photoelectric conversion area with different film thicknesses into three areas so as to have a sensitivity peak for each of the wavelengths of red, blue, and green, which are the three primary colors of light. For patterns etc., it is sufficient to have at least two photoelectric conversion areas. In addition, by selecting any color other than the three primary colors and forming a plurality of charge conversion areas, the selected specific color can be changed to i! It is also possible to configure the system to perform a wide range of determinations. Furthermore, it is also possible to select any color along with the three primary colors and correct the color discrimination based on the selected color.

Further, in order to operate the color sensor element, it is necessary to apply a bias voltage, and it is also possible to configure this bias voltage to be different for each photoelectric conversion area having a different film thickness. In this way, since the peak wavelength of the spectral sensitivity characteristic of the amorphous semiconductor can be changed by the bias voltage, the sensitivity of the color sensor element according to the present invention can be further increased.

Furthermore, a selective absorption film may be provided on any surface of the plurality of photoelectric conversion areas of the color sensor element.

Furthermore, it is also possible to configure a color sensor element group by arranging a large number of the obtained color sensor elements in a plane, and use this color sensor element group as a color image sensor.

In addition, if the amount of photoelectric conversion is large and leakage current between adjacent photoelectric conversion areas is not a problem, there is no need to cut and divide the amorphous semiconductor layer, etc., within the scope of the present invention. The invention can be implemented with various modifications, improvements, and modifications.

A glass substrate was used as an insulating substrate, and ITO was deposited in a predetermined shape as a first common electrode on the glass substrate. Next, 200 layers of amorphous silicon carbide a-5SC:N were deposited on top of the ITO, followed by 20,000 layers of i-layer deposited thereon.

The surface of the obtained amorphous silicon semiconductor layer was divided into three equal parts, and the film thickness of one layer was reduced to one third by 5,500 layers using photolithography and CF dry etching techniques, as shown in Figure 1. , the remaining one-third was distributed to 2,000 people. Thereafter, approximately 1000 aluminum A1 layers were deposited on the amorphous silicon semiconductor layer.

Next, the aluminum and amorphous silicon semiconductor layers deposited by photolithography were cut, and the amorphous silicon semiconductor layers were made into photoelectric conversion layers with different H thicknesses, and aluminum was formed as a second electrode.

The bias voltage for the obtained color sensor element is ■, 0.
．． The sensitivity to the wavelength was examined by applying a voltage of 1.5 cm and irradiating each photoelectric conversion area with a different i-layer thickness with light whose wavelength was changed sequentially.

As a result, when the thickness of the i-layer is 2000, the change in sensitivity to the wavelength of light is obtained as a curve as shown in Figure 2,
A sensitivity peak of 15 was observed around a wavelength of about 48 on-.

Further, when the thickness of the i-layer was 5500, the change in sensitivity with respect to the wavelength of light was obtained as a curve as shown in FIG. 3, and a sensitivity peak was obtained at a wavelength of about 560 nm+m.

Furthermore, when the thickness of the i-layer was 20,000 nm, the change in sensitivity with respect to the wavelength of light was obtained as a curve as shown in FIG. 4, and a sensitivity peak was obtained around a wavelength of about 650 nm.

[Effects of the Invention] The color sensor element of the present invention has a thickness of an amorphous semiconductor layer, particularly preferably an i of an amorphous silicon semiconductor layer.
Taking advantage of the fact that the sensitivity peak as a spectral characteristic changes when the thickness of the layer changes, at least two photoelectric conversion areas with different film thicknesses are provided, and the photocurrent and charge generated in these photoelectric conversion areas are Since it is configured to discriminate colors by relatively comparing amounts and performing arithmetic processing, there is no need to fix the color filter film or change the bias voltage for each element, eliminating the problems associated with this. . In other words, since there is no peeling of the color filter film or deterioration due to aging, the life of the color sensor element is greatly improved, and there is no need for a means to apply a bias voltage that is changed to each element, making the device easier to use. The structure of the color sensor element becomes simple, and it becomes possible to provide an inexpensive color sensor element.

Moreover, multiple photoelectric conversion areas can be microfabricated using photolithography, etc., and microscopic color sensor elements can be manufactured. The present invention has excellent effects such as being able to construct a highly accurate color image sensor.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an embodiment of a color sensor element according to the present invention, in which FIG. 1(a) is a plan view, FIG. 1(b) is a front view,
Figure (c) is a right side view. Figures 2 to 4 show the i of the amorphous silicon semiconductor layer.
These are characteristic curve diagrams showing the relationship between the wavelength of light and the sensitivity by changing the thickness of the layer. Figure 2 is a characteristic curve diagram when the thickness of the i-layer is 2000, and Figure 3 is the characteristic curve diagram when the thickness of the i-layer is 2000. Figure 4 shows the characteristic curve diagram when the film thickness of iN is 5500.
FIG. 10; Insulating substrate 12: Transparent electric bridge (first common electrode) 14; Amorphous semiconductor layer 16: 2 layers 18; I layer 20, 22, 24i second electrode 26; Color sensor element patent applicant Kanebuchi Kagaku Kogyo Co., Ltd. No. 14

Claims (5)

[Claims] (1) a first common electrode deposited on an insulating substrate; and at least two, preferably three, amorphous semiconductor layers laminated on the first common electrode so as to have different thicknesses. and a second electrode deposited on each of the amorphous semiconductor layers having different thicknesses. (2) The amorphous semiconductor layer is made of silicon or silicon-based material, and has at least an i-type amorphous semiconductor layer, and the i-type amorphous semiconductor layer has a different thickness. The color sensor element according to claim 1, characterized in that the color sensor element is constructed as follows. (3) The amorphous semiconductor layer is made of silicon or silicon-based material, and the amorphous semiconductor layer has a pi-type, ni-type, pin-type or nip-type structure,
The thickness of the i-type amorphous semiconductor layer is from 1000 Å to 300 Å.
3. The color sensor element according to claim 1, wherein the color sensor element differs within a range of 00 Å. (4) The insulating substrate is a transparent substrate, and the first common electrode is a transparent electrode made of a transparent conductive film. Color sensor element. (5) A color sensor element group, characterized in that a large number of the color sensor elements are arranged in a plane.