JPH09311213A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a conductive color filter produced by micelle electrolytic method without mixing a film-type foreign matter. SOLUTION: A colloid soln. is prepared by using water-soluble or water- difficult-to-be-dissolved pigment particles and ITO as conductive particles. The pigment particles gives <50μΩ<-1> cm<-1> specific conductivity when 5.0g of the pigment is dissolved in 100ml water and then measured. The prepared colloid soln. is subjected to ultrasonic dispersion and left to stand to obtain a pigment micelle colloid soln. The micelles are broken by electrolysis and precipitate the pigmet particles and transparent conductive particles on a transparent electrode. Thus, the color filter is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter used in active and passive color panels used in liquid crystal televisions, displays for personal computers and the like.

[0002]

2. Description of the Related Art A water-soluble or sparingly water-soluble pigment particle is colloidally dispersed in an aqueous micelle solution of a surfactant having redox reactivity, and the aqueous micelle solution is electrolyzed to form a predetermined pattern used as an anode. The present inventors have already applied for a patent for a method of manufacturing a color filter using a method of forming a pigment film on a transparent electrode having a shape. Further, a patent has also been filed for a method for producing a conductive micelle color filter in which hydrophobic conductive particles are co-deposited on this color filter (JP-A-2-267298).
Issue). In addition, a method for forming an inorganic film by hydrophobizing a substance whose surface of inorganic particles is hydrophilic has already been filed. Thus, we have invented a method for manufacturing a conductive micellar color filter.

[0003]

However, the above-mentioned prior art has the following problems.

It was found that when a micelle colloid solution was prepared by using the prior art that has already been filed, a film-like foreign substance different from the pigment and the conductive particles was present in the liquid. This foreign substance is considered to be an unreacted coupling agent generated in the step of hydrophobizing the conductive particles, and is insoluble in water, and is therefore considered to precipitate in the micellar colloid solution. Furthermore, when a color filter layer was formed using this micellar liquid and the film surface was observed with a microscope, the same foreign substances as those existing in the liquid having a size of about 1 to 100 microns were found to be attached or mixed in or traces of their removal. It was This is the following fatal defect in the case of a liquid crystal panel.

[0005] 1) Adhesion of foreign matter causes short-circuiting between electrodes or short-circuiting between substrates due to the foreign matter, poor alignment of liquid crystal due to uneven surface roughness, and the like.

2) The trace of foreign matter becomes a point defect when the panel is turned on.

That is, although the conductive color filter layer can be formed by the conventional method, there is no means for producing a color filter in which foreign matter is not mixed.

[0008] Therefore, an object of the present invention is to solve the above problems and to provide a conductive micelle color filter which is sufficiently applicable to active and passive type color liquid crystal panels and which is free of foreign matter. .

[0009]

Means for Solving the Problems As a result of repeated studies for achieving the above object, the present inventors have found that the above film-like foreign matter is
There are many ionic impurities in the micelle colloidal liquid, especially in the pigment, and the specific conductivity is 50 μΩ ^-1 cm ^-1.
It was found that the above is promoted and that it is likely to occur. That is, by controlling and reducing the ionic impurities in the pigment, it is possible to suppress the generation of the foreign matter. Generally, specific conductivity of the pigment that has not been purified to remove ionic impurities, 100μΩ ^-1 cm ^- 300μΩ from mu ^{1 -1} cm ^- a mu of about ^1, by purification, 50Myuomega It can be ^-1 cm ^-1 or less. Therefore, we have succeeded in suppressing the generation of foreign matter by using a pigment having the following specific electric conductivity. The specific conductivity specified here is a value measured by dissolving 5.0 g of a water-soluble or sparingly water-soluble pigment used for forming a pigment film in 100 ml of water. Secondly, when the particle size of the pigment is larger than 7,000 angstroms, it was found secondly that when the pigment layer was formed, plate-like particles were deposited on one surface and the surface of the film became very rough. That is, when an STN color panel is produced using this pigment, it causes alignment defects and the like. Generally, smaller pigment particles are better in terms of quality, but there is a problem that the cost becomes high when the particle size is 200 angstroms or less. Therefore, we have succeeded in producing a pigment layer having a smooth film surface by using a pigment having the following particle size.

That is, in the method for manufacturing a color filter of the present invention, a transparent electrode is formed on a transparent substrate, the transparent electrode is processed into a predetermined pattern, and then the transparent electrode is used as an anode on the transparent electrode by a wet electrolysis method. In the method for forming a pigment film to form a pigment film, transparent conductive particles having water-soluble or sparingly water-soluble pigment particles and a hydrophobic surface, a surfactant having a redox reaction and a supporting salt as basic components, Method for producing a color filter in which a pigment micelle colloid aqueous solution in which pigment particles and the transparent conductive particles are surrounded by the surfactant is prepared, and the micelles are destroyed by electrolysis to deposit the pigment particles and the transparent conductive particles on the transparent electrode. At the water 100m
The specific conductivity of pigment particles measured by dissolving 5.0 g of a water-soluble or sparingly water-soluble pigment used for forming a pigment film in ¹ is smaller than 50 μΩ ⁻¹ cm ⁻¹ ,
The diameter of the water-soluble or slightly water-soluble pigment particles is 7
It is also characterized in that it is 000 angstroms or less.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail using embodiments. In addition, the specific conductivity specified here is a water-soluble or slightly water-soluble pigment used for forming the pigment film,
It is a value measured by dissolving 5.0 g in 100 ml of water.

(Example 1) Red pigment particles (disanthraquinonyl red: specific conductivity 14.0 μΩ ^-1 cm ^-1 , particle diameter 1000 Å), and yellow pigment particles (disazo yellow HR: specific conductivity 33. 6 μΩ ^-1 cm
⁻¹ , a particle diameter of 3000 Å, and ITO (Indium Tin Oxide) as conductive particles were used to prepare a red pigment colloid aqueous solution having the following composition. The pigment particles used were manufactured by Dainichi Seika.

Dianthraquinonyl red 8.0 g / l Disazo yellow HR 1.6 g / l Ferrocenyl PEG 3.4 g / l LiBr (supporting salt) 10.5 g / l Hydrophobized ITO particles 18.0 g / l The above pigments The colloidal aqueous solution was ultrasonic
After ultrasonic dispersion for 0 minutes, the mixture was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. The average particle size of this liquid was 4700 angstroms.

Here, the amount of film-like foreign matter existing in the micelle liquid was counted. It is known that many foreign substances are generated when the micelle colloid liquid is strongly stirred. Therefore. The amount of foreign matter was measured after a small amount of the micelle colloid solution was placed in a sample tube and shaken for 1 minute. About 1 ml of the prepared micellar colloid solution is spread on a slide to a size of about 2 × 2 cm, and the number of foreign matters existing when scanning from one end to the other with a microscope (× 200) is counted.

As a comparative example, a conventional pigment (disanthraquinonyl red: specific electric conductivity 150 μΩ ⁻¹ cm ⁻¹ , particle diameter 1
A micellar colloid solution was prepared in the same manner using 000 angstroms, similarly disazo yellow: specific electric conductivity 300 μΩ ⁻¹ cm ⁻¹ , particle diameter 3000 angstroms), and the amounts of foreign substances were compared. The characteristic data are shown in Table 1.

[0016]

[Table 1]

As can be seen from Table 1, when a micellar colloidal liquid was prepared using the pigment particles having a specific electric conductivity of the present invention,
The amount of foreign matter was drastically reduced as compared with the case where the conventional pigment was used.

In this aqueous micelle solution, a glass substrate (2 × 3 cm) having the above electrode pattern as an anode,
A stainless steel substrate was immersed in the cathode side, and electrolysis was performed at a constant potential of +0.8 V for 15 minutes. The glass substrate was coated with a silver paste for conducting the power source and then connected to the power source, and the glass substrate was immersed to a water level such that the electrode to be the color filter layer and the counter electrode as the anode were completely immersed in the liquid. As a result, a red pigment film was formed on the ITO electrode. After washing this substrate with water, it was baked at 180 ° C. for 30 minutes. When the film thickness of the red pigment was measured, there was no difference in film thickness between the peripheral portion and the central portion of the electrode, and the film thickness was 1.05 μm evenly on the substrate surface.
Further, the film formation surface was observed by the same method as described above. As a comparative example, a conventional pigment was used to form a film by the same method, and the amounts of foreign substances were compared. The characteristic data are shown in Table 2.

[0019]

[Table 2]

From Table 2, when the pigment particles having a specific electric conductivity of the present invention were used to form a film, a uniform film surface was obtained without any foreign matter adhering thereto.

(Example 2) Blue pigment particles (phthalocyanine blue R: specific electric conductivity of 18.2 μΩ ^-1 cm ^-1 , particle diameter 2)
000 angstroms), and also purple pigment particles (dioxane violet: specific electric conductivity 33.2 μΩ ⁻¹ cm ⁻¹ ,
A blue pigment colloid aqueous solution having the following composition was prepared using ITO as a conductive particle and a particle diameter of 600 angstrom). The pigment particles used were manufactured by Dainichi Seika.

Phthalocyanine blue R 5.2 g / l Dioxane violet 0.9 g / l Ferrocenyl PEG 3.7 g / l LiBr (supporting salt) 10.5 g / l Hydrophobized ITO particles 18.0 g / l Aqueous solution of the above pigment colloid With an ultrasonic disperser
After ultrasonic dispersion for 0 minutes, the mixture was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. The average particle size of this solution was 3480 angstroms.

The amount of foreign matter was measured by the same method as for the red micelle colloid solution. As shown in Table 1, the conventional pigment (phthalocyanine blue: specific electric conductivity 19.0 μΩ ⁻¹ cm ⁻¹ , particle diameter 40
00 angstrom), also using dioxane violet: specific electric conductivity of 55.0 μΩ ⁻¹ cm ⁻¹ , particle size of 700 angstrom), the amount of foreign matter was reduced by using the pigment of specific electric conductivity of the present invention. .

In this aqueous micelle solution, a glass substrate (2 × 3 cm) having the above-mentioned electrode pattern as an anode,
A stainless steel substrate was immersed in the cathode side, and electrolysis was performed for 15 minutes at a constant potential of + 0.6V. The glass substrate was coated with a silver paste for conducting the power source and then connected to the power source, and the glass substrate was immersed to a water level such that the electrode to be the color filter layer and the counter electrode as the anode were completely immersed in the liquid. As a result, a blue pigment film was formed on the ITO electrode. After washing this substrate with water, it was baked at 180 ° C. for 30 minutes. The film thickness of the blue pigment was measured, and it was found that there was no film thickness difference between the peripheral portion and the central portion of the electrode, and that the film thickness was uniform within the substrate surface and was 0.98 μm. As shown in Table 2, when the film-forming surface was further observed by the same method as described above, it was a uniform film surface without adhesion of foreign matters and the like.

(Comparative Example 1) Red pigment particles (dianthraquinonyl red: specific electric conductivity of 100 μΩ ⁻¹ cm ⁻¹ ) and yellow pigment particles (disazo yellow: specific electric conductivity of 300 μΩ)
^-1 cm ^-1 ) and ITO as the conductive particles, a red pigment colloid aqueous solution having the following composition was prepared. The pigment particles used were made by Mikuni dye.

Dianthraquinonyl red 6.1 g / l Disazo yellow 4.1 g / l Ferrocenyl PEG 3.3 g / l LiBr (supporting salt) 10.5 g / l Hydrophobized ITO particles 10.8 g / l The above pigment colloid Use an ultrasonic dispersion device to
After ultrasonic dispersion for 0 minutes, the mixture was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. The average particle size of this solution was 5000 Å.

As shown in Table 1, the amount of film-like foreign matter present in the micellar colloid solution was measured by the same method as in Example 1 and found to be 140.

In this aqueous micelle solution, a glass substrate (2 × 3 cm) having the above electrode pattern as an anode,
A stainless steel substrate was immersed in the cathode side, and electrolysis was performed at a constant potential of +0.8 V for 15 minutes. The glass substrate was coated with a silver paste for conducting the power source and then connected to the power source, and the glass substrate was immersed to a water level such that the electrode to be the color filter layer and the counter electrode as the anode were completely immersed in the liquid. As a result, a red pigment film was formed on the ITO electrode. After washing this substrate with water, it was baked at 180 ° C. for 30 minutes. When the film thickness of the red pigment was measured, there was no film thickness difference between the peripheral portion and the central portion of the electrode, and the film thickness was 1.20 μm evenly within the substrate surface. When the film-forming surface was observed, foreign matter of about 10 to 100 μm adhered to the surface, and a large number of traces of the foreign matter were generated. As shown in Table 2, 2c with a microscope (× 200)
When the number of foreign substances was counted while scanning about m, there were 20 foreign substances. This is because, when a liquid crystal panel is used, a short circuit between electrodes or a short circuit between substrates due to foreign matter, poor alignment of liquid crystal due to uneven surface roughness occurs, and a trace of foreign matter becomes a point defect when the panel is turned on. Become.

Comparative Example 2 Blue pigment particles (phthalocyanine blue: specific electric conductivity 150 μΩ ⁻¹ cm ⁻¹ ) and purple pigment particles (dioxane violet: specific electric conductivity 200 μ)
Ω ⁻¹ cm ⁻¹ ) and ITO as the conductive particles were used to prepare a blue pigment colloid aqueous solution having the following composition. The pigment particles used were made by Mikuni dye.

Phthalocyanine blue 5.2 g / l Dioxane violet 0.9 g / l Ferrocenyl PEG 4.6 g / l LiBr (supporting salt) 10.5 g / l Hydrophobized ITO particles 18.0 g / l 9 by ultrasonic disperser
After ultrasonic dispersion for 0 minutes, the mixture was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. The average particle size of this solution was 4000 Å.

As shown in Table 1, the amount of film-like foreign matter present in the micelle colloid solution was measured by the same method as in Example 2 and found to be 450.

A glass substrate (2 × 3 cm) having the above electrode pattern as an anode and a stainless steel substrate on the cathode side were immersed in this aqueous micelle solution, and electrolysis was performed at a constant potential of +0.6 V for 15 minutes. The glass substrate was coated with a silver paste for conducting a power source and then connected to the power source, and the glass substrate was immersed to a water level where the electrodes to be the color filter layer and the counter electrode as the anode were completely immersed in the liquid. As a result, a blue pigment film was formed on the ITO electrode. After washing this substrate with water, it was baked at 180 ° C. for 30 minutes. When the blue pigment film thickness was measured, there was no difference in film thickness between the peripheral portion and the central portion of the electrode, and it was 0.90 micron in terms of uniform film thickness within the substrate surface. When the film-forming surface was observed, foreign matter of about 10 to 100 μm adhered to the surface, and a large number of traces of the foreign matter were generated. As shown in Table 2, 2c with a microscope (× 200)
When the number of foreign matters was counted while scanning about m, it was 45. This is because, when a liquid crystal panel is used, a short circuit between electrodes or a short circuit between substrates due to foreign matter, poor alignment of liquid crystal due to uneven surface roughness occurs, and a trace of foreign matter becomes a point defect when the panel is turned on. Become.

(Embodiment 3) Two 30 cm square glass substrates were prepared, ITO used as a transparent electrode for each was formed by sputtering, and further, by photolithography, 0.08 mm as a color filter substrate.
Width, 640 at 0.1 micron pitch x 3 = 1920
As a counter electrode, a stripe pattern consisting of 480 stripes having a width of 0.28 mm and a pitch of 0.3 mm was formed in the direction orthogonal to the electrodes of the color filter. The pattern ends were patterned into a predetermined shape so that a liquid crystal driving IC could be mounted in a later step. First, a black matrix layer having a width of 0.2 mm and a film thickness of 0.8 to 1.0 μm is formed between the transparent electrodes on the color filter side (the number of patterns: 1920) by a photolithography method. Then, using the pigments / compositions used in Examples 1 and 2, an electro-chemical method was used to form a conductive dye layer on a predetermined ITO transparent electrode in the order of B, G and R in the order of 0.7 to 7, respectively.
0.9 μm, 0.8 to 1.0 μm, 0.8 to 1.0 μm
Was formed. Here, the electrochemical method is
Water-insoluble or sparingly soluble pigment particles (R: dianthraquinonyl red, G: phthalocyanine green, B: phthalocyanine blue, Y: disazo yellow, V: dioxazine violet) and hydrophobized ITO particles,
Furthermore, a surfactant that is charged by electrolysis (ferrocene PE
G) and a supporting electrolyte (lithium bromide) as basic components, and a pigment and ITO particles surrounded by a surfactant to prepare a pigment and ITO micellar colloid aqueous solution,
This micelle is destroyed by electrolysis (0.4 to 1.0 V),
The conductive pigment thin film is formed by depositing pigment particles and ITO particles on the transparent electrode.

After forming three colors, it is baked at 180 ° C. for 30 minutes. After that, apply a 0.2 μm flattening film,
By firing at 80 ° C. for 1 hour, a conductive micelle color filter having a maximum difference in film thickness between the conductive dye layer and the black matrix layer of about 0.2 μm was produced.

By using this color filter and the counter substrate, a predetermined liquid crystal panel forming process is performed to obtain STN.
A color liquid crystal panel was produced. As a result of measuring the display unevenness and defects of the panel by driving 1/240 Duty, as compared with the STN color liquid crystal panel manufactured using the conventional pigment,
No short circuit between electrodes, short circuit between substrates, defective liquid crystal alignment and point defects when the panel was lit, which were considered to be caused by foreign matter, were not observed.

Comparative Example 3 An STN color liquid crystal panel was prepared under the same conditions as in Example 3 using the conductive micelle color filter side substrate prepared using the pigments and compositions of Examples 3 and 4, and under the same conditions. Driven by. As a result, a short circuit between substrates, a liquid crystal alignment defect, and a point defect when the panel was turned on were considered to be caused by foreign matter.

Example 4 Blue pigment particles (phthalocyanine blue R: specific electric conductivity 18.0 μΩ ⁻¹ cm ⁻¹ , particle diameter 7,000 Å) which differ greatly from Example 2 only in particle diameter, and also purple pigment particles (dioxane) Violet: specific electric conductivity of 35.0 μΩ ⁻¹ cm ⁻¹ , particle size of 700 Å) and ITO as conductive particles,
A blue pigment colloidal aqueous solution having the following composition was prepared. In addition,
The pigment particles used were made by Dainichiseika.

Phthalocyanine blue R 5.2 g / l Dioxane violet 0.9 g / l Ferrocenyl PEG 3.7 g / l LiBr (supporting salt) 10.5 g / l Hydrophobized ITO particles 18.0 g / l The above pigment colloid aqueous solution With an ultrasonic disperser
After ultrasonic dispersion for 0 minutes, the mixture was left for half a day. The supernatant was collected to obtain a pigment micelle colloid aqueous solution. The average particle size of this liquid was 4400 angstroms.

The amount of foreign matter in the form of a film present in the micellar colloid solution was measured by the same method as in Example 2.
It was 60 pieces.

A glass substrate (2 × 3 cm) having the above electrode pattern as an anode and a stainless steel substrate on the cathode side were immersed in this aqueous micelle solution, and electrolysis was performed at a constant potential of +0.6 V for 15 minutes. The glass substrate is coated with silver paste to keep the power supply connected, and then connected to the power supply.
The electrode to be the color filter layer and the counter electrode as the anode were soaked to the water level that they were completely immersed in the liquid. This results in IT
A blue pigment film was formed on the O electrode. After washing this substrate with water, it was baked at 180 ° C. for 30 minutes. When the blue pigment film thickness was measured, there was no difference in film thickness between the peripheral portion and the central portion of the electrode, and it was 1.00 micron in terms of uniform film thickness within the substrate surface. Further, when the film-forming surface was observed by the same method as described above, it was a uniform film surface with no foreign matter attached. However, the surface condition of the film became very rough because particles on the plate were present on one side. When this deposited layer is used as a color filter for STN as a color filter, it may cause defective alignment, and therefore cannot be used as a color filter for STN.

[0041]

As described above, according to the present invention, the specific conductivity of pigment particles measured by dissolving 5.0 g of a water-soluble or sparingly water-soluble pigment used for forming a pigment film in 100 ml of water was measured. When a micellar colloidal solution is prepared using a pigment characterized by having a degree of less than 50 μΩ ⁻¹ cm ^−1, it is possible to eliminate the foreign matter generated in the micellar solution and the foreign matter present in the film after film formation. is there. This can be judged by the fact that when a micellar colloidal solution is prepared using the pigment of the present invention, the foreign matter does not adhere to the color filter layer deposited by the micellar electrolysis method.

[0042]

Claims (2)

[Claims] 1. A pigment film is formed by 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 the method, water-soluble or water-insoluble pigment particles and transparent conductive particles having a hydrophobic surface, a surfactant and a supporting salt having a redox reaction as a basic component,
Manufacture of a color filter in which a micellar colloid aqueous solution of a pigment in which the pigment particles and the transparent conductive particles are surrounded by the surfactant is prepared, and the micelles are destroyed by electrolysis to precipitate the pigment particles and the transparent conductive particles on the transparent electrode. In the method, a water-soluble or water-insoluble pigment used for forming the pigment film is used.
A method for producing a color filter, wherein the specific conductivity of pigment particles measured by dissolving 5.0 g in 100 ml of water is smaller than 50 μΩ ⁻¹ cm ⁻¹ . 2. The method for producing a color filter according to claim 1, wherein the diameter of the water-soluble or slightly water-soluble pigment particles is 7,000 angstroms or less.