JPS59227171A - Color sensor - Google Patents

Abstract

PURPOSE:To realize a low-priced and easily integrable color sensor by a method wherein, when hereto P-N junction diodes are respectively constituted of an organic semiconductor film having a different spectrum of photo absorption at the visible region and semiconductor thin films having a different electric conductive type from that of the organic semiconductor film and the diodes are provided on the same substrate and are constituted into the color sensor for detection of three colors of blue, green and red, pigment material consisting of the three colors are specified. CONSTITUTION:A transparent electrode 46 is adhered on a transparent substrate 47 having a filter 48, which is transparent at the visible region and absorbs near infrared rays, provided on the back surface, and a blue sensitive element 401, a green sensitive element 402 and a red sensitive element 403 are respectively formed thereon at an interval. In this constitution, the element 401 is constituted of a laminated body of a merocyanine pigment 21, which is a P type semiconductor, an N type semiconductor 44 made of ZnO, and an electrode 45; the element 402 is constituted of a laminated body of the merocyanine pigment 21 and a merocyanine pigment 22, which have respectively a different spectrum of photo absorption, and the semiconductor 44 and the electrode 45, and the element 403 is constituted of the merocyanine pigments 21 and 22, a phthalocyanine layer 23, the semiconductor 44 and the electrode 45.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a color sensor for three-color discrimination of blue, green, and red.

(Prior art) Conventional color sensors generally separate light from an object to be recognized into three color bands of blue, green, and red using a prism or optical filter, and three light receiving sensors are used for each of these three color bands. was identified as a corresponding configuration.

In recent years, two-dimensional light receiving sensors such as so-called CCD sensors have been put into practical use, and these include blue and green.

Attempts have been made to construct a two-dimensional color sensor by combining color filter arrays with integrated red pigments.

Such a color sensor combines a color filter that separates target object light and a light-receiving sensor, but the process of creating the color filter is particularly complicated, and the optical relationship between the light-receiving sensor and the color filter is This method has drawbacks such as hindering mass production, which requires extremely high precision, and increasing costs.

(Purpose of the Invention) As a result of numerous tests and studies aimed at solving these drawbacks, the inventors of the present invention have discovered that the three primary color filter functions of blue, green, and red can be achieved by using an organic semiconductor using a specific pigment that constitutes the light-receiving diode. The present invention can be realized by a combination of laminated thin films, and it is possible to solve the above-mentioned cost problem by eliminating the need for coupling a photodiode with a sicolor filter, and to provide a color sensor that is inexpensive and easy to integrate. This is what led us to discover this and arrive at this invention.

(Structure of the Invention) That is, the present invention provides a hetero-t'lpn diode formed by an organic semiconductor thin film having different absorption spectra in the visible region, and a semiconductor thin film or metal thin film having a different electrical conductivity type from the organic semiconductor, Blue color with LED or Schottky diode configured on the same substrate.

A color sensor for detecting three colors of green and red.

The organic semiconductor thin film is a layered layer of blue: merocyanine dye I, green: merocyanine color series I and 2, red=7 talocyanine M material, and the above dye 1. This is a color sensor composed of multiple laminated layers of II.

First, it will be explained that a filter function for the three primary colors, that is, blue, green, and red, can be imparted by selecting a semiconductor thin film using dyes (or pigments) and structuring them in layers, which will be described in detail later.

FIG. 1 shows the light absorption spectra in the visible region of organic semiconductor thin films made of merocyanine dyes I and II represented by the following formulas (1) to (3) used in the present invention and phthalocyanine pigments. The first company mentioned above is the merocyanine pigment, and the second one is that of the same pigment 1.3, which is specifically that of magnesium 7 and cyanine.

It is known that these organic semiconductors form Schottky barrier diodes with metals, and in this case, the photosensitivity spectrum matches the light absorption spectrum.

It is clear from FIG. 1 that merocyanine dye I has blue light absorption characteristics, and the dye I film alone functions as a blue filter.

Next, merocyanine dye 2 exhibits light absorption characteristics in both blue and green color bands, and as shown in Figure 2(a), merocyanine dye 2
1 and dye 1122 are laminated and irradiated with white light 20. Due to the filtering action of dye i21, the light absorption spectrum by the dye 22 is shaped into a light absorption spectrum with only a marginal color band as shown in FIG. 2(b). Ru.

Furthermore, it is generally known that 7-thalocyanine-based Ichiki semiconductors exhibit a wide optical absorption spectrum spanning the green, red and near-infrared bands, and the optical absorption spectrum of the above-mentioned magnesium phthalocyanine, as an example, is shown in Figure 1. (3) eξ is shown. Similarly, as shown in FIG. 3(b), the above merocyanine dye (212) and magnesium phthalocyanine (33) were layered and irradiated with white light (30). As a result, the green band components were removed and the red band and near-infrared band. This near-infrared absorption characteristic can be removed using a filter that is transparent in the visible region and absorbs in the near-infrared.

As detailed above, the merocyanine dye I produces a blue band of light, the lamination of the same merocyanine dye (■) and the dye (■) produces a green band of light, and the lamination of these dyes (■, ■) and magnesium phthalocyanine produces a red band of light. It is clear that it is possible to create a layered structure of an organic semiconductor using these dyes so as to absorb each of the colors, thereby enabling color discrimination.

Example Next, the present invention will be specifically explained based on embodiments.

FIG. 4 is a cross-sectional view showing the structure of a color sensor according to the present invention. On a transparent substrate 47 on which a transparent electrode 46 is formed,
Blue photosensitive element 401 to be described later. Green photosensitive element 402. and a red photosensitive element 403 are formed using a known thin film forming method using vapor deposition, photolithography, selective etching, and the like. In the figure, 21 is dye I, 22 is dye ■,
Furthermore, 33 is a phthalocyanin, 44 is a ZnOn type semiconductor (
or A/), 45 is an electrode, 40 indicates the incident direction of the object light to be recognized, and 48 is a filter that is transparent in the visible region and absorbs near infrared rays; an example of such a filter is shown in FIG. The light-receiving mechanism of the present invention, in which a commercially available colored glass filter having such light transmission characteristics can be used, will be described using the red light-sensitive element 403 as an example. The merocyanine dye I21, the dye 1122 and the seventh cyanine layer 33 are all p-type semiconductors, and 44 is an n-type semiconductor made of ZnOK.
It is a type of semiconductor. The ZnO semiconductor may be a metal such as A/, but as is known, what contributes to the photocurrent are hole and electron carriers generated by light absorption near the pn junction or near the shot barrier. is a ZnO semiconductor, since ZnO is transparent in the visible region, it is the carriers generated on the side of the cyanine layer 33 that contributes to the photocurrent. If the carriers generated in the dye 122 and the dye 1[42 are selected to be similar to those in the p-region depletion layer, the carriers generated in the dye 122 and the dye 1[42] will hardly contribute to the photocurrent, and the photocurrent wavelength characteristic will be similar to the light absorption characteristic diagram in the phthalocyanine. I will do it.

Therefore, the dye 121 and the dye 22 act only as filters.

Also, the layer shown in 44 above is AI! Even when forming a Schottky barrier such as the like, it is known that carriers generated within the depletion layer of the organic semiconductor 33 contribute to the photocurrent. Consistent with the light absorption (optical density) characteristics within layer 33.

Regarding the blue light-sensitive element 401 and the green light-sensitive element 402, it is similarly clear that the respective photocurrent wavelength characteristics match the light absorption (optical density) within the same dye I21 and color gl122.

From the above, the absorption characteristics of the color sensor according to this embodiment are shown in the diagram shown in FIG. 6, where 61 represents the sensitivity characteristics of the blue light-sensitive element, 62 represents the sensitivity characteristics of the green light-sensitive element, and 63 represents the sensitivity characteristics of the red light-sensitive element. ing.

By configuring this embodiment as described above, each photosensitive element for identifying the three primary colors can be configured on the same substrate without using an optical filter for separating the three primary colors of green and red. be able to.

FIG. 7 shows another embodiment, in which the blue, green, and red light receiving elements described above are set as a set and are two-dimensionally arranged on the same substrate 707.

Since such a color sensor is constructed of a vapor-deposited film, it has the advantage that a large-area color sensor can be obtained at low cost.

(Effects of the Invention) The present invention achieves optical properties for three primary colors by selecting and using organic semiconductor thin films having the above characteristics constituting a pn junction or a Schottky barrier diode, and by combining them to form a multi-layer structure. It can be equipped with a filter function, and it is possible to detect the color of object light without using a conventional color filter. Moreover, according to the structure of the present invention, it is formed of a vapor-deposited film, so it is easy to manufacture. The above problems are solved, and the industrial effect is extremely high, especially as a large-area, highly integrated line or surface sensor can be obtained at low cost.

[Brief explanation of the drawing]

Figure 1 is a diagram of the light absorption characteristics of merocyanine dye 1, merocyanine dye 2, and magnesium phthalocyanine, and Figure 2 (a) is a cross-sectional view of the laminated structure of merocyanine dye 1 and dye 2. Figure 2 (b) is a light absorption characteristic diagram for the same introduction, Figure 3 (a)
is the same dye 1. II and a cross-sectional view of the magnesium phthalocyanine thin film laminated structure, and FIG. 3(b) is a diagram of the absorption characteristics of the same. FIG. 4 is a structural cross-sectional view of an embodiment of the present invention, FIG. 5 is a transmittance characteristic diagram of a commercially available near-infrared cut filter, FIG. 6 is a photosensitivity characteristic diagram of a color filter of the present invention, and FIG. FIG. 7 is a plan view showing another embodiment of the present invention in which color sensors are two-dimensionally arranged. 21... Merocyanine dye 1.22... Same dye ■,
33... Phthalocyanine fi material, 20, 30, 40.
...Light 1.44- ZnOn type semiconductor, 45-... Electrode, 47°707... Transparent substrate, 401,402,40
3... Evening color, green, and red photosensitive elements. Patent Applicant Oki Electric Industry Co., Ltd. Figure 4 40 Figure 7 51;-□1 Chief of Figure 6 (nm) Procedural Amendment November 51, 1973 Kazuo Wakasugi, Commissioner of the Patent Office 1, Indication of the Case Showa 1958 Patent Application No. 101001! 2,
Name of the invention Color sensor 3, Relationship with the case of the person making the amendment Patent Applicant (029) Oki Electric Industry Co., Ltd. 4, Agent 5, Daily publication of the amendment order ゛ Showa year, month, day (voluntary) 6, Amendment As shown in the appendix of Section 7 of the detailed explanation of the subject invention, contents of the amendment (1) Chemical formula (3) on page 4 of the specification, the following passages are all corrected. Record

Claims (1)

[Claims] Blue, green and A color sensor for detecting three colors of red,
A color sensor comprising, as the organic semiconductor thin film, a laminated layer of blue: metecyanine dye (■), green: merocyanine dye I and H, and further a laminated layer of red niathalocyanine pigment and the above-mentioned dyes I and II. .