JPS6020721B2 - Polychromatic optical filter and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polychromatic optical filter and a method for manufacturing the same.

color image pickup tube or color charge-coupled device (CCD)
:Char coupled device), charge injection device (CID:Charge injectionD
A color solid-state image sensor, such as a color solid-state image pickup device, etc., uses a polychromatic optical filter in the form of a multicolor stripe or a multicolor mosaic.

Typically, a polychromatic optical filter is one in which the three colors red, green, and blue or the three colors cyan, magenta, and yellow are regularly arranged in a stripe or mosaic pattern.
The color composition is not necessarily limited to these three colors, and may consist of two colors, four colors, or more. Conventionally known polychromatic optical filters can be roughly divided into two types: interference filters and dye filters.

That is, the interference filter is, for example, Japanese Patent Publication No. 40-859 P.
As described in Samurai Publication No. 47-27742, Japanese Patent Publication No. 50-23247, and Japanese Patent Publication No. 50-44414, interference of multiple layers is used to obtain predetermined optical characteristics on a transparent substrate such as glass. The dye filter is provided with a membrane, and the dye filter is disclosed in, for example, Tokusekki No. 47-37237, Japanese Unexamined Patent Publication No. 4
8-6373 number, JP-A No. 48-16 Isokyu and Tokko-Ko 5
A typical example is one in which a regularly arranged hydrophilic polymer layer is dyed with a dye, as described in various publications such as No. 3-248. This also includes those in which a dye image is formed by a type color development method. Among these polychromatic optical filters, interference filters are particularly excellent in terms of spectral characteristics, but the process for making filters for each color is extremely complicated.
A polychromatic optical filter obtained by repeating this process for every two or three colors inevitably becomes very expensive.

On the other hand, dye filters have the advantage that the process is simpler than the process for obtaining interference filters, and that a relatively inexpensive filter can be obtained. In particular, the method previously proposed by the present inventors (Tokubuta 53-17831
According to the method of obtaining a multicolor optical filter by exposing the black and white silver halide emulsion layer for each color and performing external color development, it is possible to obtain a multicolor optical filter in a very easy way. Moreover, if this method is followed, it also has the unique effect of forming a pure black pattern called optical flak, which is required for a polychromatic optical filter for a color image pickup tube. Therefore, by combining the respective advantages of these interference filters and dye filters, it is possible to manufacture the most preferable polychromatic optical filter.

The present inventors have carefully studied the dye filters among these polychromatic optical filters, and found that when comparing interference type filters and dye type filters, dye type filters have spectral characteristics such as cyan or blue. I found out that there is something wrong with being inferior.

FIG. 1 shows the cyan spectral characteristics of a typical interference filter and the cyan spectral signature {B} of a typical dye filter.

Compared to interference filters, cyan dye filters have a short wavelength side (around 400 nm to 49 mm) and a long wave side (around 50 mm).
Disadvantages include low transmittance at distances from 60 m to 60 m) and discoloration. On the other hand, it was found that the yellow spectral characteristics of the dye filter were equivalent to those of the interference filter. Therefore, it is expected that a striped filter with good spectral characteristics can be obtained by combining a cyan interference filter and a yellow dye filter.

Although it is described in Japanese Patent Publication No. 52-4129 that two stripe filters are bonded together to form one stripe filter, this method is an invention in which filters of the same type are bonded together, and an interference filter and a dye are bonded together. The above-mentioned technical idea of combining the advantages of each filter is not presented.

The present invention has been made in consideration of these matters, and therefore, the purpose of the present invention is to provide a multi-layer filter that can obtain spectral characteristics equivalent to those of an interference filter, and that has a simpler manufacturing process than an interference filter, and therefore can be manufactured at a lower cost. An object of the present invention is to provide a color optical filter and a method for manufacturing the same. The object of the present invention is to provide an interference filter constituted by regularly arranging multilayer dielectric thin films having predetermined optical properties on a transparent support, and a silver halide emulsion provided covering the interference filter layer. A structure of a polychromatic optical filter characterized by having a dye filter formed by regularly arranging dye images having optical characteristics different from those of the interference filter in a layer by an external color development method, and a transparent multicolor optical filter. Imagewise exposure is performed on a silver halide emulsion layer of a photographic material in which a silver halide emulsion layer is coated on an interference filter constructed by regularly arranging multilayer electroconductive thin films having predetermined optical properties on a support. , an image containing a dye and silver having optical characteristics different from those of the interference filter is formed in a regular array by external color development, and then the silver in the image containing the dye is bleached to form a dye filter. This is achieved by a method for manufacturing a polychromatic optical filter characterized in that a dye filter of at least one color is formed by repeating the same process of forming a dye filter different from the above dye if necessary.

Hereinafter, the polychromatic optical filter of the present invention and its manufacturing method will be explained in more detail with reference to FIGS. 2 to 10.

2 to 6 show the steps of forming an interference filter. FIG. 2 shows a state in which a multilayer interference film 11 is provided on a transparent support I0 such as glass, and FIG. FIG. 4 shows the state in which the layer 12 is provided, and the state in which the photoresist layer is exposed in a pattern and then the photoresist is developed to form a relief 13 and an exposed portion 14 of the interference film. .

FIG. 5 shows a state in which the exposed interference film is removed by a suitable method such as wet etching, plasma etching, reactive ion etching, ion etching, etc., so that the support 10 is exposed. FIG. 6 shows a stripe filter 16 formed by removing the stripe strip. A silver halide emulsion layer 17 is provided on the interference filter thus obtained as shown in FIG. 7, and after exposing the filter pattern to light, when external color development is performed, silver and dye are formed in the exposed area 18 as shown in FIG. is formed, and silver halide remains as it is in the unexposed areas 19 within the pattern and the unexposed areas 20 outside the pattern.

After bleaching the silver formed in the exposed area (it may be eluted or re-halogenated), the unexposed area 20 outside the pattern area is exposed to light, and black-and-white development or external color development is performed. Then, an optical black 21 of silver or silver and dye is obtained in the exposed area (FIG. 9). Finally, the silver halide in the unexposed area is removed by fixing, and the 10th
As shown in the figure, interference filter 16, dye filter 18''
, an optical black 21' is obtained. Although the support 10 used in the present invention needs to be transparent, it may be in any form such as a plate, a sheet, or a film.

Examples of materials used for the support include plastics such as polyethylene terephthalate, polystyrene, polycarbonate, and cellulose acetate, glass, quartz, and sapphire. Further, the support itself may have other uses; for example, one of the supports, for example 11 in the figure, may be a face plate of an imaging tube. As for the method of manufacturing the interference filter 11 used in the present invention, for example, all of the above-mentioned known methods can be used, and the interference filter 11 is formed to have, for example, cyan spectral characteristics.

Here, the interference filter 11 has two different spectral characteristics.
Of course, it is also possible to use a filter with more than just a color.
A silver halide emulsion layer is then applied onto the interference filter 11 thus formed to form a photographic material as shown in FIG. Particularly fine grain emulsions are preferred, such as so-called Lippmann emulsions in which the average grain size of silver halide is 0.1 m or less.

This photographic material is imagewise exposed through a photomask, for example, in a color different from the spectral characteristics of the interference filter, i.e., in a pattern corresponding to the second color of the polychromatic optical filter to be formed, such as a yellow striped or mosaic pattern. will be carried out.

The light source used in this exposure may be any light source that emits light at a wavelength to which the silver halide emulsion layer is sensitive; for example, a light source that emits white light is used. The exposed photographic material is then subjected to a first outer mold color development.

For example, when such a photographic material is developed with an external color developing solution containing a yellow coupler, a pattern consisting of yellow dye and silver particles is formed in the exposed areas. After this development is completed, the photographic material is bleached of the silver particles of the pattern. To bleach silver particles, use an aqueous solution of an alkali metal dichromate or ammonium salt and sulfuric acid, or an aqueous solution of a ferrician compound and potassium bromide, which are known in the photographic industry as a sterilizing solution or a bleaching solution.
In particular, a bleaching solution is used that satisfies the following conditions: it does not destroy the latent image, it does not dissolve the silver halide in the unexposed area, and it does not destroy the dye. As a result, the silver particles and undeveloped silver nuclei generated by the first color development are dissolved and removed, or these silvers are re-halogenated and destroyed, so that the pattern by the first color development does not contain development nuclei. Since there is no silver present, unless such a pattern is subjected to imagewise exposure again, color mixing will not occur in the color development process for the second color or later, which will be performed later as necessary, or in the optical black development process described later. 0 When a pattern of two or more colors is formed in the emulsion layer, the pattern obtained by repeating the same process after performing color development for the second and subsequent colors will have no warm color at all.

In this way, after the dye pattern of, for example, yellow in FIG. Although it may be formed, it is most effective to form it by the following method.

That is, in this method, the unexposed areas of a photographic material on which a multicolor pattern has been formed are exposed to an optical black pattern in the same manner as the exposure method for each color pattern, and then black-and-white development or external color development is carried out. In this method, the silver halide in the unexposed areas and/or the colored pattern is removed by fixing.

When black-and-white development is used to obtain optical black, the optical black consists of silver, and it is difficult to achieve an optical density of 4.0 or higher, but when external color development is performed, it is easy to achieve an optical density of 4.0 or higher. concentration is obtained.

Therefore, forming optical black by external color development is a particularly advantageous embodiment of the present invention.

When black-and-white development is performed, the optical density may be slightly lower than 4.0, but the optical density may be used as it is, or the optical density may be increased to 4.0 or higher using known intensification. As explained in detail above, according to the present invention, spectral characteristics equivalent to those of an interference filter can be obtained, and the manufacturing process is simpler than that of an interference filter, so a polychromatic optical filter can be obtained at a lower cost. Even if only the manufacturing process is compared with a dye filter using a dyeing method, which is relatively easy to manufacture although it is inferior in terms of quality, the present invention has a significant effect in that the manufacturing process is much simpler.

This is because the external color development method not only facilitates the step of forming a dye pattern, but also facilitates the formation of optical black.

[Brief explanation of the drawing]

FIG. 1 is a graph showing typical cyan spectral characteristics of interference filters and dye filters, and FIGS. 2 to 10 are side sectional views showing an example of the process for manufacturing the polychromatic optical filter of the present invention. 10: Support, 11: Interference filter, 17: Silver halide emulsion layer, 18, 18', 18'': Dye filter,
21: Optical black. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Scope of Claims] 1. An interference filter configured by regularly arranging multilayer dielectric thin films having predetermined optical properties on a transparent support;
Dye images having a different arrangement and different optical properties from those of the interference filter are regularly arranged in a silver halide emulsion layer provided to cover this interference filter layer using an outside color development method. 1. A multicolor optical filter comprising: a dye filter; 2. The polychromatic optical filter according to claim 1, wherein optical black is formed in the same layer as the layer in which the dye image is formed. 3 Imagewise exposure is applied to a silver halide emulsion layer of a photographic material in which a silver halide emulsion layer is coated on an interference filter constructed by regularly arranging multilayer dielectric thin films having predetermined optical properties on a transparent support. Then, by external color development, an image containing a dye and silver in an arrangement different from that of the interference filter and having different optical properties is formed in a regular array, and then the silver in the image containing the dye is bleached. A method for manufacturing a multicolor optical filter, characterized in that a dye filter is formed, and if necessary, a similar process of forming a dye filter different from the above dye is repeated to form a dye filter of at least one color. 4. Manufacture of a multicolor optical filter according to claim 3, characterized in that after the final color development process, an optical black pattern is exposed and fixed after performing black and white development or external color development. Method.