JPH052106A - Color filter - Google Patents

Abstract

PURPOSE:To improve the light resistance of colored picture elements formed by dyeing and the spectral characteristics of colored picture elements formed by pigment dispersion. CONSTITUTION:The colored picture elements of the color filter are formed by laminating the colored picture elements 14, 15 formed by dyeing of dyes and the colored picture elements 16 of the hues varying from each other formed by the dispersion of pigments, by which the light resistance of the colored picture elements formed by the dyeing is improved. The spectral characteristics intrinsic to the colored picture elements by the dispersion of the pigments are improved by the combination with the colored picture elements by the dyeing with which the arbitrary spectral characteristics are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter, and more particularly to a color display filter used in a color liquid crystal display or a color separation filter for an image pickup device such as CCD.

[0002]

2. Description of the Related Art In recent years, color filters have been used in liquid crystal displays, viewfinders for video cameras, CCDs.
Industrial products using various color filters, which are used for color separation filters of image pickup devices such as, color image sensors, line sensors for color copying, and the like, are being developed.

The colored pixels of these color filters are formed by methods such as a dyeing method, a pigment dispersion method, an electrodeposition method, a vapor deposition method and a printing method. Among them, the dyeing layer and the pigment dispersion method are the main ones.

The formation of the colored pixel of the color filter by the dyeing method is formed by the photolithography technique and the dyeing technique. In the dyeing method, a colloid prepared by mixing a water-soluble polymer such as gelatin, casein, or polyvinyl alcohol with a photosensitive cross-linking agent such as chromate or dichromate is used as a light-sensitive material, and spin coating or the like is used to perform a predetermined process. After pre-baking after forming to a film thickness, the resulting photosensitive film is exposed using an exposure device such as a mask aligner, and the dyed pattern obtained by elution of the unexposed area by spray development with water is obtained. Dye with an acid dye or a reactive dye. Next, an intermediate layer of a resin such as acrylic, urethane, or epoxy is formed as a dye-proof layer.
There is also a method of carrying out dye-resisting by a chemical reaction of tannic acid or the like without using such an intermediate layer. A color filter is formed by repeating this series of steps in the same manner for the three primary colors of red (R), green (G), and blue (B).

The characteristics of the color filter by the dyeing method can be exemplified as follows compared with the color filter by other methods. That is, (1) Since the plate is made by the photolithography method,
It is possible to form fine colored pixels (2 μm or less).

(2) There is a wide variety of dyes, and by combining a plurality of dyes, various spectral characteristics can be obtained, that is, there is a large degree of freedom in the spectral characteristics. On the other hand, the method for forming colored pixels of a color filter by the pigment dispersion method is as follows: a colloid of a transparent photosensitive resin obtained by mixing dichromate with a water-soluble polymer such as casein, gelatin, polyvinyl alcohol, etc. The photoconductor liquid in which the pigment is dispersed is applied by a method such as spin coating, and is formed by the photolithography technique as in the dyeing method color filter.

The characteristics of the color filter manufactured by the pigment dispersion method can be listed as follows as compared with the color filters by other methods. That is, since (1) the plate is made by the photolithography method similarly to the colored pixel of the dyeing method, it is possible to form a minute colored pixel (up to about 10 μm).

(2) By selecting an appropriate pigment,
Light fastness, that is, light resistance, heat resistance, chemical resistance,
It is superior to dyes in physical properties such as water resistance.

(3) The process is simplified because a dyeing process and a dye-proofing process are not required unlike the color filter by the dyeing method.

[0010]

The colored pixel of the color filter formed by the dyeing method can easily obtain a color filter having a predetermined spectral characteristic by selecting a desired one from abundant dyes. Since it uses a dye, there are few dyes that can satisfy the physical properties required as a color filter in terms of light resistance such as color change when exposed to light, durability such as water resistance, heat resistance, and chemical resistance. . In addition, when a solution containing a dye is adsorbed to the organic substance layer which becomes the base of the colored pixel, the organic base swells, and further cracks or the like are caused by a temperature change due to heating or cooling in a later step. However, there is a problem that the light transmission characteristics and the appearance are deteriorated. Further, if a high density colored pixel is to be formed by a dyeing method, there are means for adsorbing a large amount of dye or for making a dyed substrate a thick film.
In these methods, the stress of the substrate increases and cracks and the like are likely to occur. For this reason, it is difficult to obtain a high-density colored pixel by the dyeing method.

Further, in the case of forming a colored pixel by the pigment dispersion method, there are very few pigments having desired spectral characteristics while satisfying the dispersibility and transparency of the pigment with respect to the binder resin holding the pigment, and particularly blue. Alternatively, the green colored pixel is limited to a phthalocyanine-based pigment or the like. Also,
Due to the light reflecting action of the pigment particles, there is a problem that the saturation of the colored pixel is low and the brightness is reduced when an attempt is made to obtain a colored pixel of sufficient density.

[0012]

In order to solve the above problems, the present invention provides a colored pixel of a color filter with a colored pixel formed by a dyeing method and a hue of the colored pixel formed by the dyeing method. Formed by stacking colored pixels formed by a pigment dispersion method of different hues, in particular, the colored pixels obtained by the dyeing method and the colored pixels obtained by the pigment dispersion method are colored pixels of different hues, and the dyed layer and In addition to compensating for the drawbacks of both of the pigment dispersion methods, a color filter having further excellent spectral characteristics is obtained.

FIG. 1 is a sectional view showing an example of the color filter of the present invention. Pixels 12 and 13 colored by dispersing a pigment are formed on a substrate 11 such as quartz glass, dyed pixels 14 and 15 are formed thereon, and a surface protective layer 16 is further formed. A color filter having such a structure is particularly suitable for a pasting type color filter. That is, referring to light, colored pixels in which a pigment having excellent light resistance is dispersed are arranged in advance, and light passing through the colored pixels passes through pixels colored with a dye. It is greatly attenuated, and the light resistance of the entire colored pixel is significantly improved as compared with the pixel colored with the dye alone. In particular, it is suitable when a dye that cannot be used for a color filter is used because the durability is low even if the spectral characteristics of color are satisfied.

FIG. 2 shows a cross-sectional view of a filter in which a color layer in which a pigment for color correction is dispersed is formed. The substrate 21 such as quartz glass has a color layer 2 in which a yellow pigment is dispersed.
2, and a colored layer 23 dyed blue on top of
Colored layer 24 dyed red, colored layer 2 dyed green
5 is formed. A surface protective layer 26 is provided on these colored layers. The coloring layer in which the pigment is dispersed serves as a color correction for correcting the color tone common to the pixels of the three filters of blue, red and green dyes.

Further, in these cases, since the spectral characteristics of the color filter are determined by the spectral characteristics of the dye layer, the degree of freedom in selection can be increased.

The method for producing a color filter of the present invention comprises:
A colored pixel in which a pigment is dispersed is formed on a substrate and is immersed in a dyeing solution to dye the dyeing substrate to form a colored pixel. In this method, since the final dyeing is performed, it is easy to finely adjust the spectral characteristics.

Regarding the hue of the colored pixel of the present invention, the colored pixel due to dyeing and the colored pixel due to dispersion of the pigment have different hues and can be used for the correction of the sensitivity for each color of the CDD. When used as a color filter of a color liquid crystal display device, color correction can be performed.

For example, a fluorescent lamp or an electroluminescent element is usually used as a backlight for liquid crystal, but when the color temperature of these light sources and the color filter do not match, Y ( By forming the (yellow) colored pixel, the color temperature of the light source can be lowered, and the display color of the color filter can be made correct.

Further, since the light of a specific wavelength in the transmitted light is attenuated due to the influence of the gap of the liquid crystal cell, it may become colored light. In such a case, the color of the colored pixel is selected. By doing so, it becomes possible to correct the color.

Alternatively, since the liquid crystal itself is colored, the transmitted light may have a specific color, but similarly, color correction can be performed by utilizing the spectral characteristic of the colored pixel.

FIG. 3 shows an embodiment in which the color filter of the present invention is applied to a color liquid crystal display device.

The color liquid crystal display device 31 is provided with the color filter 32 of the present invention, and the glass substrate 33.
A colored pixel 34 in which a pigment is dispersed is provided on the upper side, and a colored pixel 35 colored with a dye having a hue different from that of the pigment is provided on the colored pixel in which the pigment is dispersed. The colored pixels colored with dyes are R (red) and G so that color display is possible.
It is composed of three colored pixels of (green) and B (blue). A protective film is formed on the colored pixels, and a transparent electrode 36 for operating the liquid crystal is further provided. A counter substrate 38 having a TFT element or a transparent electrode film 37 formed thereon is provided so as to face the color filter. The color filter and the counter substrate are bonded by a sealing material 39, and a liquid crystal 40 is sealed inside. There is.

The color liquid crystal display device 31 is provided with a light source 41 such as a fluorescent lamp, which transmits the deflector plate 42, the color filter and the liquid crystal on which a predetermined image pattern is formed, and through the deflector plate 43. Is displayed.

The "hue" in the present invention means, for example, red, blue and green colors of each color in a primary color type color filter, and includes black although it is achromatic. In a complementary color type color filter, it refers to magenta, yellow, cyan, green, or yellow, cyan, green. The "different hue" in the present invention, which is achromatic but contains black, means that the colored pixel in which the pigment is dispersed and the pixel colored with the dye do not have the same hue.

[0025]

According to the present invention, since the colored pixels in which the dye is adsorbed and the colored pixels in which the pigment is dispersed are laminated, the characteristics possessed by the respective colored pixels are exhibited, and therefore, those having arbitrary spectral characteristics can be easily obtained. As a result, a colored pixel is obtained which has both the characteristics of the dye having excellent saturation and the characteristics of the pigment having excellent durability such as light resistance to incident light. Moreover, because the hues of the two colored pixels that are stacked are different,
It is possible to perform output correction and color correction for each color.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the color filter of the present invention is used as a color filter such as CCD for a solid-state image pickup device will be described.
As shown in (A), it is formed on the surface of a substrate 51 such as quartz glass. After sufficiently washing this substrate, a coating layer 52 of a photosensitive material in which the yellow pigment shown in Table 1 is dispersed is formed by spin coating.

[0027]

[Table 1]

Next, as shown in FIG. 4 (B), an ultraviolet ray 53 is used for exposure through a photomask having a predetermined pattern.

As shown in FIG. 4C, the unexposed portion is spray-developed with water to form predetermined colored pixels 54.

Next, as shown in FIG. 4D, a coating layer 55 of a photosensitive material in which the blue pigment shown in Table 1 is dispersed is formed, and exposed by ultraviolet rays through a predetermined photomask (see FIG. 4). (E)), colored pixel 56 by spray development with water
Are formed (FIG. 4 (F)). On the colored pixel in which the pigment is dispersed, a photosensitive material in which a water-soluble polymer such as casein, gelatin, or polyvinyl alcohol is mixed with a substance having a function of crosslinking the water-soluble polymer by light, such as ammonium dichromate To form a coating film. The coating film is exposed through a photomask on which a predetermined pattern is formed, and the unexposed portion is dissolved by spray development with water to form a dye substrate pattern 61 that forms a colored pixel of the first color. It is formed on the colored pixel 54 (FIG. 5).
(A)).

The substrate having the dyed substrate pattern formed thereon is immersed in the red dyeing solution shown in Table 2 to form red colored pixels 62 (FIG. 5 (B)).

[0032]

[Table 2]

Then, it is treated with a dye-resisting agent such as tannic acid and potassium antimonyl tartrate, and dyed with a dyeing solution having the composition shown in Table 2 in the same manner as in the first color, and then the second color.
Colored pixel 5 in which the blue (blue) colored pixel 63 and the third color (green) colored pixel 64 are dispersed with the blue pigment.
6 (FIG. 5 (C)).

After the colored pixels are laminated in this way,
After forming a protective film consisting of a coating layer of a transparent synthetic resin such as acrylic resin, the color filter was accurately aligned with the CCD and bonded. When the CCD with the color filter was irradiated with light of 3000 lux from the halogen lamp for 500 hours, no change was observed in the color signal output.

On the other hand, when a CCD to which a color filter having only colored pixels formed by dyeing is attached is irradiated with light under the same conditions, a color signal output of 15% for blue, 5% for green and -4% for red is output. Was observed. CCD
As a single unit, no change in signal output was observed with this level of light irradiation, and the change in color signal output was due to the change in the spectral characteristics of the color filter due to light irradiation.
Thus, it was revealed that the color filter of the present invention improves the weather resistance.

In the color filter of this embodiment, colored pixels are formed on the substrate separately from the solid-state image pickup device such as CCD, and these are attached to the CCD. The color filter may be directly formed. In this case, colored pixels formed by dyeing in sequence and then colored pixels in which pigments are dispersed may be stacked on the solid-state image sensor.

Further, according to the purpose of correcting the hue, the colored pixels in which the pigment is dispersed may correspond to the colored pixels formed by dyeing one to one, or one to a plurality or one to a plurality. It may be allowed to.

Next, the second color filter of the present invention is used.
As an embodiment of the present invention, a case where the invention is applied to a color liquid crystal display device will be described.

Length 300 mm, width 300 mm, thickness 1.5
After coating the photosensitive resin in which the pigment having the composition shown in Table 3 is dispersed to a thickness of 1.5 μm on a quartz glass substrate having a thickness of 1.5 mm, 2
It was exposed to ultraviolet light from a kW ultra-high pressure mercury lamp and cured. On this, red, blue and green colored pixels were formed with the same composition of the dyeing solution as in the first embodiment using a desired photomask.

[0040]

[Table 3]

After forming a protective film on the color filter thus formed, a transparent electrode was formed to form a color filter.

The color liquid crystal cell thus obtained has a color temperature of 5500.
When a K fluorescent lamp is used for the backlight, the color temperature of the backlight is 33 due to the colored pixels in which the yellow pigment is dispersed.
A color liquid crystal display device in which the color is converted to 00K and blue is suppressed can be obtained. This color temperature correction can be arbitrarily selected by changing the color temperature of the yellow colored pixel.

Further, the color difference between the colored pixels of each color before and after the accelerated weather resistance test was carried out on the color filter of this example and the color filter colored only by dyeing using a weather resistance tester specified in JIS B7753. △ E
Table 4 shows the measurement results of (difference in color difference according to L ^* u ^* v ^* colorimetric system defined in JIS Z8730).

[0044]

[Table 4]

As shown in Table 4, the color filter of the present invention was capable of improving the weather resistance simultaneously with the color correction.

[0046]

According to the present invention, the colored pixel of the color filter is formed by stacking the colored pixel formed by the dyeing method and the colored pixel formed by the pigment dispersion method and having different hues from each other. The problems of light resistance, heat resistance, chemical resistance, water resistance, etc. of the colored pixel are solved by forming a colored pixel by the pigment dispersion method, and A spectral characteristic can be combined with a colored pixel by a dyeing method to obtain a color filter having an arbitrary spectral characteristic.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a color filter of the present invention.

FIG. 2 is a sectional view showing an embodiment of a color filter in which a common color correction layer is formed of pigment.

FIG. 3 is a sectional view showing an embodiment of a color liquid crystal display device.

FIG. 4 is a cross-sectional view showing the manufacturing process of the color filter of the invention.

FIG. 5 is a cross-sectional view showing the manufacturing process of the color filter of the invention.

[Explanation of symbols]

11 ... Substrate, 12, 13 ... Pixel in which pigment is dispersed, 14,
15 ... Dyeed pixels, 16 ... Surface protective layer, 21 ... Substrate,
22 ... a pigment-dispersed colored layer, 23 ... a blue-tinted colored layer, 24 ... a red-tinted colored layer, 25 ... a green-tinted colored layer, 26 ... a surface protective layer, 31 ... a color liquid crystal display device, 32 ... Color filter, 33 ... Glass substrate,
34 ... Colored pixel, 35 ... Colored pixel colored with dye, 37
... Transparent electrode film, 38 ... Counter substrate, 39 ... Sealing material, 40
... liquid crystal, 41 ... light source, 42 ... deflector, 43 ... deflector, 5
1 ... Substrate, 52 ... Photosensitive material coating layer, 53 ... UV ray,
54 ... Colored pixel, 55 ... Photosensitive material coating layer, 56 ... Colored pixel, 61 ... Dyeing substrate pattern, 62 ... First colored pixel, 63 ... Second colored pixel, 64 ... Third colored Pixel

Claims (2)

[Claims] 1. A color filter in which colored pixels are regularly formed on a substrate, wherein the colored pixels are a stack of colored pixels formed by dyeing and colored pixels in which a pigment having a hue different from that of the dye is dispersed. A color filter characterized by being present. 2. The color filter according to claim 1, wherein the laminated colored pixels are provided with colored pixels in which a pigment is dispersed on the side on which light is incident.