JPH0139272B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color solid-state image sensor plate, and more particularly to a single-plate or two-plate color solid-state image sensor plate that extracts two or more types of color signals from one solid-state image sensor. .

Solid-state imaging color cameras include CCD, MOS, and BBD.
By arranging a mosaic-like or stripe-like color separation filter, for example, each filter element of red, green, and blue (hereinafter abbreviated as R, G, and B, respectively), facing each pixel of a solid-state image sensor such as It extracts R, G, and B color signals. Solid-state imaging devices have a complicated electrode structure on the Si surface, and due to absorption of each electrode, the spectral sensitivity characteristics tend to be poor in the short wavelength region of the visible range, as shown in FIG. 1, for example. Figure 1 shows the spectral sensitivity characteristics of CCD, but other than CCD, such as MOS, BBD, etc.
Since Si is used, absorption occurs in the short wavelength region, and the spectral sensitivity exhibits the same tendency as shown in FIG.

In order to construct a color camera using such a solid-state image sensor, it is necessary to obtain a color signal through a color separation filter. The spectral characteristics of the device generally have the characteristics shown in FIG. Examples of such color separation filters include organic dyed filters in which organic resin is colored with dyes, dichroic filters, and the like.

Figure 3 shows an example of the optical system of a solid-state color camera.
The image is focused on the sensitive area of the image. Each filter element of the color separation filter layer 3 is arranged to correspond to each pixel of the solid-state image sensor 4. As a method of arranging the color separation filter layer, there is a method in which the color separation filter layer is formed on a transparent substrate and is placed in correspondence between the color separation filter and the solid-state image sensor via a relay lens (hereinafter referred to as
(referred to as relay lens method), a method in which a color separation filter layer is formed on a transparent support and is laminated with an adhesive corresponding to each pixel of a solid-state image sensor (hereinafter referred to as bonding method), and solid-state image sensor There is a method of processing and arranging a color separation filter directly on top (hereinafter referred to as the direct method). Figure 3 shows an example of the direct method. As shown in FIG. 3, an element in which a color separation filter layer is directly provided on the solid-state image sensor 4 is referred to herein as a color solid-state image sensor for convenience. In addition, because solid-state image sensors have particularly high sensitivity in the near-infrared region, and color separation filters have transmission characteristics in the near-infrared region, unnecessary signals may be superimposed, resulting in brightness and chromaticity errors. In order to prevent this, an infrared cut filter 2 is usually placed between the color separation filter 3 and the imaging lens 1. Figure 4 shows the spectral transmittance characteristics of the infrared cut filter.

From the above, the overall sensitivity of each color signal of the solid-state image sensor of the solid-state color camera is as shown in FIG. Furthermore, FIG. 6 shows the output of each color signal obtained from the solid-state image sensor.

In this way, the output level of each color signal differs greatly. For example, the B signal is 1/3 of the G signal.
The output will be 1/4. In such a case, the R signal or the G signal is mixed into the B signal, or the B signal is relatively small, resulting in S/N deterioration of the B signal, which significantly deteriorates color reproducibility as a color camera.

An object of the present invention is to provide a color solid-state image sensor plate that solves the above-mentioned problem in which the output levels of each color signal differ greatly, that is, to provide a color solid-state image sensor that has uniform output levels.

The present invention provides a sensitivity existing on the light receiving surface of a solid-state image sensor that has a constant overall sensitivity characteristic such that the output level of each color is constant, for example, the color separation filter has a spectral transmittance characteristic as shown in FIG. The color separation filter layer is characterized in that a correction filter layer is layered on the color separation filter layer so as to cover the entire surface of the filter element provided on the color separation filter layer.

Below, regarding the above-mentioned present invention, frame transfer method
The application to a CCD color solid-state image sensor will be explained in detail based on the drawings as an example. First, FIG. 7 is a schematic cross-sectional view showing a structural example of a color solid-state image sensor plate according to the present invention. The color solid-state image sensor plate shown in FIG. 7 has a color separation filter layer 12 (an example in which R, G, and B color elements are provided) is provided on the sensitive part 11 present on the light-receiving surface of the solid-state image sensor. , and further has a structure in which a correction filter layer 13 is provided thereon.

In the above example, the color separation filter layer is the eighth
If the correction filter layer has the spectral transmittance characteristics shown in Figure 8a and is a pale cyan color having the spectral transmittance characteristics shown by p in Figure 8a, then the spectral transmission of the color separation filter The rate characteristics are shown in FIG. 8b.

Therefore, when the color solid-state imaging device plate of the present invention having a filter portion having such spectral transmittance characteristics images an object through an infrared cut filter, the overall sensitivity becomes as shown in FIG. 9,
Each of the R, G, and B color signals obtained from the solid-state image sensor becomes as shown in FIG. 10, and each output signal is made uniform, and problems such as a high output level signal being mixed into a low output level signal can be improved. High quality color images can be obtained.

As a method for manufacturing the color solid-state image sensor plate of the present invention, an organic resin such as casein, gelatin, or green is made into a plate on at least a portion of the light-receiving surface of the solid-state image sensor that includes the photosensitive area, and the spectral characteristics of each color are colored with an organic dye. After forming a filter element with a colorable organic resin in the same manner, Nippon Kayaku Co., Ltd.
Kayanor Milling Turquis Blue 3G, Kayanor Milling Ultra Sky
SF, Kayacion Turquis PGF or Mitsubishi Chemical Industries, Ltd. Diamond Brilliant Sky Blue
It is best to form a correction filter layer by staining with PW, Diacid Light Blue 2A, etc. Alternatively, a method may be used in which each filter element is formed after forming the correction filter layer. However, when a color separation filter is colored to have spectral characteristics of each color, it is usually colored while measuring the spectral transmittance characteristics, so it is easier to manufacture by forming each filter layer after forming the correction filter layer.

Although the organic dyeing filter has been explained above, it is clear that it is also possible to form the color separation filter layer or the correction filter layer with a multilayer interference thin film. It is possible for the filter layer to be formed by an organically dyed filter and vice versa. It is also possible to form the correction filter layer by vapor depositing a pigment such as phlotocyanin.

Since the present invention has the above-described configuration, it exhibits remarkable effects as listed below.

The output signals of each color of R, G, and B are made uniform, and the problem of high-output level signals mixing with low-output level signals is improved, and not only can high-quality color images be obtained, but also Uniform output levels for R, G, and B colors are achieved by using a uniform light cyan material that covers the entire surface of the color separation filter layer, without requiring a separate light shielding layer for each color filter element. A correction filter layer is provided to correct the spectral transmittance characteristics of each color filter element constituting the color separation filter layer so that the spectral sensitivity characteristics are opposite to the spectral sensitivity characteristics of the solid-state image sensor. Therefore, a desired solid-state image sensor plate can be manufactured very easily as part of the normal process of manufacturing a solid-state image sensor plate by laminating a plurality of layers.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that "parts" in the following text indicate "parts by weight."

Example: Water made of casein-ammonium dichromate was added to the area including the sensitive part of the light receiving surface of a CCD solid-state image sensor manufactured by ordinary wafer processes such as vapor phase growth, lower impurity diffusion, photolithography, metal vapor deposition, etc. After applying the photosensitive liquid to a film thickness of 0.4 μm, drying it, accurately aligning a mask with a predetermined shape to prevent the formation of the casein resin layer on the bonding pad area of the solid-state image sensor, and then applying hot water after close exposure. The non-exposed areas are removed to form a colored layer. Next, it is dyed for 2 minutes with a 0.08% aqueous solution of Kayacion Turquis PGF (60°C) manufactured by Nippon Kayaku Co., Ltd. to form a correction filter layer, and then resist-dyed with a solution of tannic acid and potassium antimonyl tartrate. Next, in the same manner, apply 0.8μ of an aqueous photosensitive solution, dry, expose using a mask with a predetermined shape, develop, dye the R filter element, and perform anti-staining treatment. form. Each filter element also includes a correction filter layer to prevent a colored layer from being formed on the bonding pad portion of the solid-state image sensor, and after the formation of each filter layer and filter element, a ring manufactured by Japan Synthetic Rubber Co., Ltd. is used to protect the color separation filter. After coating 1.0μ of transparent CBR resist, which is a butadiene-based negative resist, it was exposed and developed using a mask with a predetermined shape to form a protective film in areas other than the bonding pad area, and then heat treated at 160°C for 30 minutes to form the present invention. A color solid-state image sensor plate was fabricated. After this, the chips are made into chips by dicing, die bonding, wire bonding, and packaging are performed in the usual manner.
A single-chip color solid-state camera was fabricated.

The dye bath composition of each filter element is as follows.

R Dye Bath Kayanol Milling Ret RS (Nippon Kayaku Co., Ltd.)
1 part acetic acid 3 parts water 100 parts G dyebath Brilliant Blue (manufactured by Hoechst) 1 part Suminol Yellow (manufactured by Sumitomo Chemical Co., Ltd.) 1 part acetic acid 3 parts water 100 parts B dyebath Kayanol Cyanine 6B ( Nippon Kayaku Co., Ltd.) 1 part Acetic acid 3 parts Water 100 parts

[Brief explanation of drawings]

Figure 1 is a graph showing the spectral sensitivity characteristics of a CCD solid-state image sensor, Figure 2 is a graph showing the spectral transmittance characteristics of a color separation filter in which R, G, and B filter elements are arranged, and Figure 3 is a graph showing the spectral transmittance characteristics of a solid-state image sensor. An explanatory diagram showing an example of the optical system of a color camera, FIG. 4 is a graph showing the spectral transmittance characteristics of an infrared cut filter,
Fig. 5 is a graph showing the overall sensitivity of each color signal of the solid-state image sensor of a solid-state color camera, Fig. 6 is a graph showing the output of each color signal obtained from such a solid-state image sensor, and Fig. 7 8 is a schematic cross-sectional view showing a configuration example of a color solid-state image sensor plate according to the present invention, and FIG. 8a separately shows the spectral transmittance characteristics of the color separation filter and correction filter layer of the color solid-state image sensor plate according to the present invention. Graph, also No. 8
Figure b is a graph showing the overall sensitivity, Figure 9 is a graph showing the overall sensitivity of each color signal of the solid-state image sensor on the color solid-state image sensor plate, and Figure 10 is a graph showing each color obtained from such a solid-state image sensor. It is a graph showing the output of a signal. DESCRIPTION OF SYMBOLS 11... Photosensitive part of a solid-state image sensor, 12... Color separation filter layer, 13... Correction filter layer.

Claims (1)

[Claims] 1. A solid-state image sensor plate, characterized in that a color separation filter layer and a correction filter layer whose spectral transmittance characteristics are opposite to the spectral sensitivity characteristics of the solid-state image sensor are layered on the photosensitive portion of the solid-state image sensor.