JPH06130215A - Production of color filter - Google Patents

Abstract

PURPOSE:To provide the color filter having a uniform film thickness by forming electrodes as second anodes on the same transparent substrate in at least the region on the outer periphery of the transparent electrode part to be finally used for display as the color filter. CONSTITUTION:Electrode patterns 2 for obtaining conduction with a power source, electrode patterns 3 to constitute color filter layers and patterns 6 as the second anode electrodes in the region on the outer periphery of the electrode patterns 3 are formed at the time of forming the film of the transparent electrode ITO on a glass substrate 1. Pigment films are thereafter formed on the electrodes 3. An electrolysis is effected by immersing the glass substrate 1 as anode and a stainless steel substrate as cathode in a prescribed aq. miscelle soln. in this formation. Silver paste is applied on the electrodes 2 and after all the electrode patterns 2, 3, 6 are integrally conducted, the patterns are connected to the power source and the substrates are immersed down to the liquid level at which the electrodes 3 and the electrodes 6 are completely immersed in the soln about the glass substrate 1. Consequently, the blue pigment films are formed on the ITO electrodes.

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 for a liquid crystal display.

[0002]

2. Description of the Related Art Production of a color filter using a method of forming a pigment film on a substrate by colloidally dispersing pigment particles in a micelle aqueous solution of a redox-reactive surfactant and then electrolyzing the micelle aqueous solution. We have already filed a patent application for the method (JP-A-2-2460). This method has the advantages that a large-area color filter can be easily manufactured and that the image quality of a liquid crystal panel can be improved at low cost.

[0003]

However, when the pigment film is formed on the substrate on which the transparent electrode is patterned by the wet electrolysis method as described above, the pigment film thickness around the electrode which becomes the color filter layer is the center. There was a phenomenon that it became thicker than the part. Here, the electrode peripheral portion is an area (2 cm) inside from the outer periphery of the electrode portion 3 (all shaded portions) used for display as the color filter layer in FIG. 4 (2
The area in which the two diagonal lines intersect) (hereinafter referred to as the electrode peripheral portion 4) is shown, and the electrode central portion indicates the area further inside than the electrode peripheral portion 4 which is within 1 to 2 cm from the outer circumference ( Hereinafter, this is referred to as the electrode center portion 5). By the way, when the micelle colloid aqueous solution is electrolyzed, the micelles carrying the pigment particles diffuse near the electrodes. The diffused micelles are destroyed on the electrode and only pigment particles are deposited on the electrode to form a pigment film. It is considered that most of the diffusion and destruction of the micelles occur in the central part 5 of the electrode in the vertical direction with respect to the electrode, whereas in the peripheral part 4 of the electrode, it is presumed to occur in the vertical direction and the horizontal direction. Therefore, it is considered that the pigment particles are excessively deposited in the electrode peripheral portion 5 as compared with the electrode central portion 4 and the film thickness is increased, and a color filter having a non-uniform film thickness is formed. In a liquid crystal panel incorporating such a color filter, display unevenness occurs because the threshold voltage of the liquid crystal varies, and high contrast is not obtained. The present invention is intended to solve these problems, and to provide a color filter having a uniform film thickness.

[0004]

The method for producing a color filter of the present invention is characterized by the following.

1. In a method for producing a color filter, a transparent electrode is formed on a transparent substrate, the transparent electrode is processed into a predetermined pattern, and a pigment film is formed on the transparent electrode by using the transparent electrode as an anode by a wet electrolytic method. In addition, a pigment film is formed by forming an electrode as a second anode on the same transparent substrate in the outer peripheral region of the transparent electrode portion used for display as a color filter and electrolyzing.

2. In a method for producing a color filter, a transparent electrode is formed on a transparent substrate, the transparent electrode is processed into a predetermined pattern, and a pigment film is formed on the transparent electrode by using the transparent electrode as an anode by a wet electrolytic method. In addition, a pigment film is formed by placing an electrode as a second anode in parallel with the transparent substrate so as to be located on the outer periphery of a transparent electrode portion used for display as a color filter and electrolyzing.

3. In the method for forming a pigment film of the means 1 or 2, the water-soluble or sparingly soluble pigment particles in water, a surfactant having redox reactivity and a supporting salt are used as basic components, and the pigment particles are surrounded by the surfactant. The present invention is characterized in that a micelle colloid aqueous solution of a pigment is prepared, and the micelle is destroyed by electrolysis to deposit pigment particles on the transparent electrode.

4. In a method for producing a color filter, a transparent electrode is formed on a transparent substrate, the transparent electrode is processed into a predetermined pattern, and a pigment film is formed on the transparent electrode by using the transparent electrode as an anode by a wet electrolytic method. In the outer peripheral area of the transparent electrode portion used for display as a color filter and on the same transparent substrate, an electrode is formed as a second anode and electrolyzed to form a pigment film, and then the electrode is peeled and removed. And

5. The method of forming the electrode as the second anode of the means 4 is characterized in that a method of forming an electrode thin film with a paste containing a conductive substance or a method of forming an electrode thin film with a resin containing a conductive substance is used.

[0010]

As described above, when a pigment film is formed, an electrode is formed as a second anode on the same substrate at least in the outer peripheral region of the transparent electrode portion used for display as a color filter and electrolysis is performed. Alternatively, at least in the end, the electrode as the second anode is installed in parallel with the substrate so as to be located on the outer periphery of the transparent electrode portion used for display as a color filter, and electrolysis is performed to make it transparent in the electrolytic solution. It is considered that the diffusion and destruction of micelles in the horizontal direction around the electrodes are avoided, and excessive pigment particles are prevented from being deposited, so that the pigment film thickness within the substrate surface can be made uniform.

[0011]

【Example】

(Example 1) 1. A pigment thin film was formed on the transparent electrode as in the following steps.

As shown in FIG. 1, a transparent electrode ITO is formed on a glass substrate, an electrode pattern 2 for establishing electrical continuity with a power source during film formation, an electrode pattern 3 serving as a color filter layer, and an electrode pattern 3 serving as a color filter layer. The outer peripheral area was patterned with a pattern 6 as a second anode electrode (state of side surface of substrate, see FIG. 2). After that, a pigment film was formed on the electrode 3 serving as the color filter layer by the following method.

A pigment colloid aqueous solution having the following composition was prepared.

Monochlorocopper phthalocyanine 20 mM Ferrocenyl PEG 1 mM LiBr (supporting salt) 0.1 M The above pigment colloid aqueous solution was ultrasonically dispersed by an ultrasonic dispersing device 2
After ultrasonic dispersion for an hour, it was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. When the particle size distribution of this solution was measured by a laser particle size distribution meter, it was found that the solution had a peak at 1300 angstroms. A glass substrate having the above electrode pattern as an anode and a stainless steel substrate as a cathode were immersed in this aqueous micelle solution, and electrolysis was performed at a constant potential of +0.4 V for 20 minutes. The glass substrate is coated with a silver paste on the electrode 2 for electrical connection to the power source to conduct electrical continuity of all electrode patterns, and then connected to the power source. The electrode 6 was immersed in water up to the level at which it was completely submerged. As a result, a blue pigment film was formed on the ITO electrode.

After washing the substrate with water, the substrate is washed at 180 degrees Celsius for 3 hours.
It was baked for 0 minutes.

2. When the blue pigment film thickness was measured, there was no film thickness difference between the electrode peripheral portion 4 and the central portion 5, and the film thickness within the substrate surface was uniform and was 0.7 μm.

(Embodiment 2) 1. A pigment thin film was formed on the transparent electrode as in the following steps.

As shown in FIG. 4, a transparent electrode ITO is patterned on a glass substrate to form an electrode pattern 2 for establishing electrical continuity with a power source during film formation and an electrode pattern 3 serving as a color filter layer. A pigment film was formed by the method.

A pigment micelle colloid aqueous solution was prepared in the same manner as in Example 1, and a glass substrate having the above-mentioned electrode pattern in the micelle aqueous solution and a Pt mesh as a second anode electrode only on the outer peripheral portion of the electrode to be the color filter layer. It was brought close to and immersed in parallel with the substrate (see the front view of the substrate in FIG. 1 and the side face of the substrate in FIG. 3), and a stainless steel substrate was used as the cathode. Therefore, with a constant potential of + 0.4V, 20
When electrolysis was performed, a blue pigment film was formed on the ITO.

After washing the substrate with water, the substrate is washed at 180 ° C. for 3 hours.
It was baked for 0 minutes.

2. When the blue pigment film thickness was measured, there was no film thickness difference between the electrode peripheral portion 4 and the central portion 5, and the film thickness within the substrate surface was uniform and was 0.7 μm.

Comparative Example 1 A pigment thin film was formed on the transparent electrode as in the following steps.

A transparent electrode ITO was patterned on a glass substrate as shown in FIG. 4 to form an electrode, and a pigment film was formed thereon by the following method.

A pigment micelle colloid aqueous solution was prepared in the same manner as in Example 1, and a glass substrate having the electrode pattern and a stainless steel substrate as a cathode were immersed in the micelle aqueous solution, and electrolysis was performed at a constant potential of +0.4 V for 20 minutes. As a result, a blue pigment film was formed on the ITO.

After washing this substrate with water, the substrate is washed at 180 ° C. for 3 times.
It was baked for 0 minutes.

2. When the film thickness of the blue pigment was measured, the film thickness at the electrode center part 5 was 0.7 μm, whereas the film thickness at the electrode peripheral part 4 was 1 μm, and the film thickness within the substrate surface became uneven.

(Example 3) 1. A pigment thin film was formed on the transparent electrode as in the following steps.

A transparent electrode ITO was patterned on the glass substrate as shown in FIG. Then, around the ITO,
A silver paste was applied as in the case of the second anode electrode 6 in FIG. 2, dried, and then a pigment film was formed on the ITO by the following method.

A pigment micelle colloid aqueous solution was prepared in the same manner as in Example 1, and a glass substrate having the electrode pattern and a stainless steel substrate as a cathode were immersed in the micelle aqueous solution, and electrolysis was performed at a constant potential of +0.4 V for 20 minutes. As a result, a blue pigment film was formed on the ITO electrode.

After washing this substrate with water, the silver paste applied to the substrate was peeled off and baked at 180 ° C. for 30 minutes.

2. When the film thickness of the blue pigment was measured, the film thickness on the surface of the substrate was uniformly 0.7 μm.

Example 4 A conductive resin was applied in place of the silver paste in the same manner as in Example 3 to form a film. When the film thickness of the blue pigment was measured, the film thickness on the surface of the substrate was uniformly 0.7 μm.

[0033]

According to the present invention, it is possible to manufacture a uniform color filter without any difference in the pigment film thickness on the surface of the substrate.
Further, a liquid crystal panel incorporating the color filter,
Compared with the case of incorporating a conventional color filter,
Since there is no difference in the color tone within the panel surface and the difference in the threshold voltage of the liquid crystal, there is no display unevenness and high contrast can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a state from the front of a color filter in Examples 1, 2, 3, and 4 of the present invention.

FIG. 2 is a diagram schematically showing a side view of a color filter in Examples 1, 3 and 4 of the present invention.

FIG. 3 is a diagram schematically showing a side view of a color filter according to a second embodiment of the present invention.

FIG. 4 is a view schematically showing a transparent electrode patterned on a conventional transparent substrate.

[Explanation of symbols]

1 Transparent Substrate 2 Terminal for Mounting Liquid Crystal Panel and Electrode for Continuity with Power when Forming Pigment Film 3 Transparent Electrode to be Color Filter Layer 4 Transparent Electrode Peripheral Area 5 Transparent Electrode Central Area 6 Second Anode Electrode

Claims (5)

[Claims] 1. A method for producing a color filter, comprising forming a transparent electrode on a transparent substrate, processing the transparent electrode into a predetermined pattern, and then forming a pigment film on the transparent electrode using the transparent electrode as an anode by a wet electrolytic method. In, at least finally, a pigment film is formed by forming an electrode as a second anode on the same transparent substrate in the outer peripheral region of the transparent electrode portion used for display as a color filter and electrolyzing. Color filter manufacturing method. 2. A method for producing a color filter, comprising forming a transparent electrode on a transparent substrate, processing the transparent electrode into a predetermined pattern, and then forming a pigment film on the transparent electrode using the transparent electrode as an anode by a wet electrolytic method. In order to form a pigment film, at least in the end, an electrode as a second anode is placed close to and in parallel with the transparent substrate so as to be positioned at the outer periphery of the transparent electrode portion used for display as a color filter. And a method for manufacturing a color filter. 3. The method for forming a pigment film comprises water-soluble or sparingly water-soluble pigment particles, a redox-reactive surfactant and a supporting salt as basic components, and the pigment particles are surrounded by the surfactant. The method for producing a color filter according to claim 1 or 2, wherein an aqueous solution of a micellar colloid of a pigment is prepared, and the micelle is destroyed by electrolysis to deposit pigment particles on a transparent electrode. 4. A method for producing a color filter, which comprises forming a transparent electrode on a transparent substrate, processing the transparent electrode into a predetermined pattern, and then forming a pigment film on the transparent electrode using the transparent electrode as an anode by a wet electrolysis method. In, at least finally after forming a pigment film by forming an electrode as a second anode on the same transparent substrate in the outer peripheral region of the transparent electrode portion used for display as a color filter and electrolyzing,
A method for producing a color filter, which comprises peeling and removing the electrode. 5. The method of forming the electrode as the second anode is characterized by using a method of forming an electrode thin film with a paste containing a conductive substance, or a method of forming an electrode thin film with a resin containing a conductive substance. The method for producing a color filter according to claim 4.