JPH07128518A - Color filter - Google Patents

Abstract

PURPOSE:To efficiently produce a high-qulity color filter in good yield at a low cost. CONSTITUTION:This color filter consists of a transparent substrate 1 of glass, etc., a light shielding layer 2 consisting of an opaque metallic layer formed on one side of the substrate in the form of a pattern, a photoresist layer 3 left on the layer 2, a tricolor transparent layer of red R, green G and blue B formed to fill at least the space between the patterns of the layer 2 and a transparent protective layer 4 covering the transparent colored layer and the light shielding layer 2, and the photoresist layer 3 contains a violet pigment absorbing the wavelengths enhanced in human relative visibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter used in a color liquid crystal display device or the like.

[0002]

2. Description of the Related Art In a liquid crystal display device, a liquid crystal material is sealed between a front substrate and a rear substrate, and a voltage is applied to a transparent electrode provided on each of the front substrate and the rear substrate to drive the liquid crystal substance. It is a display device that displays a screen by controlling transmission / non-transmission of light rays. When color display is performed by this liquid crystal display device, a color filter for coloring the transmitted light in each color is applied as the front substrate or the rear substrate.

Conventionally, formation of such a color filter has been performed as follows. That is, a hydrophilic resin solution such as gelatin, glue, casein, or polyvinyl alcohol, which has been made photosensitive with dichromate, is coated on the entire surface by a spin coating method on a transparent substrate such as a glass plate, and then mask exposure is performed. A predetermined pattern is baked by the method and developed to form a relief pattern, which is dyed with an acid dye of a desired color, and then subjected to a stain-proof treatment with an aqueous tannic acid solution and an aqueous tartar solution. This process is repeated for the number of colors to form the color filter portion.

Further, in order to improve the display quality of the liquid crystal display device, a grid-like light-shielding black matrix pattern is formed at the boundary between the color sections. The light-shielding pattern is formed by forming a uniform opaque metal film on one surface of the transparent substrate in advance and then forming a relief pattern on the upper surface by a photolithography method and then exposing the exposed opaque metal film. It can be formed by etching.

[0005]

However, according to the conventional method of forming a color filter as described above, when a relief pattern has a pinhole defect when forming a light-shielding pattern, it is small. However, during the etching process, it causes a large pinhole in the opaque metal film on the lower surface, which causes a problem that the light shielding effect is reduced.

In order to eliminate such a problem, the relief pattern for forming the light-shielding pattern is formed by a photoresist containing a black colorant, and the black photoresist layer is left as it is on the light-shielding pattern. Thus, by forming the color filter portion thereon, even if a large pinhole is formed in the light-shielding pattern as described above, the deterioration of the light-shielding effect due to this large pinhole is reduced by the upper black photoresist layer. Japanese Patent Laid-Open No. 63-282702 and Japanese Patent Laid-Open No. 3-274502 disclose color filters capable of preventing a decrease in yield due to pinholes.

However, in the means described in these publications,
Photoresist photosensitive wavelength range (generally 3
The light absorptivity in the range of 20 to 450 nm) is large, and the light-shielding pattern may not be stably formed.

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to achieve high production efficiency and excellent quality.
Another object of the present invention is to provide a color filter capable of improving the yield and reducing the manufacturing cost.

[0009]

In order to achieve the above object, the color filter of the present invention comprises a transparent substrate, and a light-shielding layer consisting of an opaque metal layer formed in a pattern on one surface of the transparent substrate, A photoresist layer left on the light-shielding layer, and a transparent coloring layer formed so as to fill at least the space between the patterns of the light-shielding layer, wherein the photoresist layer has a wavelength range with high human visual acuity. It is characterized by containing a violet pigment that absorbs.

Further, the light shielding layer is formed by a photolithography method.

Further, the opaque metal layer is characterized by containing a metal selected from chromium, aluminum and copper as a main component.

Further, a transparent protective layer is provided on the entire surface including the light shielding layer and the transparent colored layer.

[0013]

According to the present invention, as described above, the transparent coloring is performed while the photoresist layer containing the violet pigment that absorbs a wavelength range having high human visual acuity is left on the light shielding layer even after the light shielding pattern is formed. Since the layer is formed, even if a small pinhole is formed in the photoresist layer, which causes a large pinhole in the lower light-shielding layer during etching, the light-shielding effect is reduced by the pinhole in the light-shielding layer. Can be mitigated by this photoresist layer to the point where it is practically problem-free.

[0014]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

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

Referring to FIG. 1, the color filter of the present embodiment comprises a transparent substrate 1 such as a glass substrate and a light shielding layer 2 composed of an opaque metal layer formed in a pattern on one surface thereof.
And the photoresist layer 3 left on the light shielding layer 2.
A transparent colored layer of three colors of red R, green G and blue B formed so as to fill at least the space between the patterns of the light shielding layer 2, and the entire surfaces of these transparent colored layer and the light shielding layer 2 are covered. The transparent protective layer 4 is provided, and the photoresist layer 3 contains a violet pigment that absorbs a wavelength range in which humans have high relative visual sensitivity.

Next, a method for forming the color filter will be described with reference to FIG. First, on one surface of the transparent substrate 1, a metal such as chromium, aluminum, or copper is deposited to a thickness of 500 to 20 by a vapor deposition method, a sputtering method, or the like.
A uniform opaque metal layer 2a having a thickness of about 00 μm is formed on the entire surface. Then, a photoresist containing a violet pigment such as Rionogen Violet RL (manufactured by Toyo Ink Mfg. Co., Ltd .; CI Pigment Violet 23) which absorbs a wavelength range having high human visual acuity on its upper surface ( For example, OFPR: trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is uniformly applied on the entire surface by a spinner or a roll coater, dried, and then exposed and developed by a mask exposure method to form a photoresist layer 3 having a predetermined pattern. Formed (see FIG. 2A).

The violet pigment contained in the photoresist layer 3 has a spectral transmittance curve as shown in FIG. 4, and it is clear from this that the human visual acuity (standard ratio shown in FIG. 5). The absorption in the high wavelength range of the luminosity curve V (λ) is large, and the transmittance of the photoresist in the photosensitive wavelength range (generally 320 to 450 nm) is good.

Such a violet pigment is preferably contained in the range of about 20 to 50% by weight with respect to the resin component of the photoresist. If the content is less than 20% by weight, the formed light-shielding film has insufficient light-shielding performance, and the contrast of the display screen is lowered. On the other hand, if the content is more than 50% by weight, the viscosity of the photoresist is increased, making it difficult to apply a photoresist layer having a uniform film thickness, or developing is difficult in the developing process and should be removed. There is a problem that the photoresist remains on the part.

Next, the exposed portion of the opaque metal layer 2a is removed by etching using the photoresist layer 3 as a mask to form a patterned light-shielding layer 2 as shown in FIG. 2 (b). Further, the photoresist layer 3 is heat-treated at a temperature of 200 ° C. or higher to give the photoresist layer 3 sufficient chemical resistance. In this way, by leaving the photoresist layer 3 containing the violet pigment on the light shielding layer 2, the step of removing the photoresist layer 3 can be omitted and the steps can be shortened. Further, as shown in FIG. 3, even if a small pinhole 3a happens to exist in the photoresist layer 3 and a large pinhole 2b is formed in the light shielding layer 2 thereunder during the etching process, this light shielding layer 2 is not formed. The reduction of the light blocking effect due to the pinhole can be reduced by the photoresist layer 3.

Next, as shown in FIGS. 2 (c) to 2 (e),
Transparent colored layers of three colors of red R, green G and blue B are sequentially formed so as to fill at least the space between the patterns of the light shielding layer 2. First, the transparent colored layer of red R is formed, for example, by coating a photosensitive resin on the entire surface, exposing and developing it in a pixel pattern, and then dyeing the remaining photosensitive resin in a pixel pattern with a red dye. Can be done (staining method). It is also possible to form a pattern by printing a printing ink in which a color pigment is dispersed on the pixel portion (printing method). Alternatively, a photosensitive resin in which a color pigment is dispersed may be applied on the entire surface, exposed, and developed into a pixel pattern (pigment dispersion method).

By repeating such a method, the green G and blue B transparent colored layers can be similarly formed.

Finally, as shown in FIG. 1, a transparent protective layer 4 is provided by coating a transparent material such as acrylic resin, urethane resin, epoxy resin, or silicon resin on the entire surface to smooth the surface. .

Further, a transparent conductive film layer (not shown) can be further formed thereon.

As the transparent conductive film layer, indium oxide and tin oxide are vacuum-deposited, and if necessary, patterned by photoetching to form a transparent conductive film layer of ITO.

In this way, the color filter is completed.

[0027]

As described in detail above, according to the color filter of the present invention, the photoresist layer containing the violet pigment that absorbs the wavelength range with high human visual acuity remains as it is after the light shielding pattern is formed. Since the transparent colored layer is formed while being left on the light-shielding layer, even if a small pinhole is formed in the photoresist layer, which causes a large pinhole in the lower light-shielding layer during etching, The reduction of the light-shielding effect due to the pinholes in the light-shielding layer can be reduced to such an extent that the photoresist layer practically eliminates the problem, and it is possible to prevent the yield reduction due to the pinholes and to reduce the photoresist layer The removal process can be omitted, and the manufacturing cost can be reduced by shortening the process.

Further, the color filter of the present invention has high production efficiency and is excellent in quality.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a method of forming a color filter of the present invention in the order of steps.

FIG. 3 is a cross-sectional view showing a part of a color filter.

FIG. 4 is a spectral transmittance curve diagram of a violet pigment.

FIG. 5 is a standard relative luminous efficiency curve diagram.

[Explanation of symbols]

 1 transparent substrate 2 light-shielding layer 2a opaque metal layer 2b pinhole 3 photoresist layer 3a pinhole 4 transparent protective layer R, G, B transparent colored layer

Claims (4)

[Claims] 1. A transparent substrate, and a light-shielding layer made of an opaque metal layer formed in a pattern on one surface of the transparent substrate,
A photoresist layer left on the light-shielding layer, and a transparent coloring layer formed so as to fill at least the space between the patterns of the light-shielding layer, wherein the photoresist layer has a wavelength range with high human visual acuity. A color filter comprising a violet pigment that absorbs. 2. The color filter according to claim 1, wherein the light shielding layer is formed by a photolithography method. 3. The color filter according to claim 1, wherein the opaque metal layer contains a metal selected from chromium, aluminum and copper as a main component. 4. The color filter according to claim 1, wherein a transparent protective layer is provided on the entire surface including the light shielding layer and the transparent colored layer.