JPH11295521A - Color filter, production of the color filter and liquid crystal display element using the color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process which solves the problems associated with a water washing stage in a process for producing color filters and well and rapidly washes dyestuff thin-film layers of color filters formed by pigment particles. SOLUTION: This process for producing the color filters having at least the stage for forming dyestuff layers of the color filters by forming electrode patterns 2 on an insulative substrate 1 and depositing the pigment particles on these electrode patterns 2, then washing the dyestuff layers with water is the process for producing the color filters by further executing washing by using liquid A7 having the surface tension smaller than the surface tension of water after water washing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color filter, a method for manufacturing the color filter, and a liquid crystal display device using the color filter.

[0002]

2. Description of the Related Art Liquid crystal display devices have been used in various fields, and are increasingly being used as information display devices on CRTs. In particular, devices that require portability are used in many devices because of their small size, light weight, and low power consumption. In addition, color technology has advanced, and dyeing methods, pigment dispersion methods,
Various methods such as an electrodeposition method, a printing method, and a micellar electrolytic method have been proposed, and some of them have been put to practical use.

[0003] The dyeing method is a method in which an anti-staining film is formed on gelatin by photolithography and dyed for each color of RGB with a dye. The pigment dispersing method is a method in which an ultraviolet curable resist in which a pigment is dispersed is used. This is a method in which a pigment layer is formed by repeating RGB exposure three times with mask exposure and thermal curing by a photolithography method after applying to a substrate. The electrodeposition method is a method in which an electrodeposited polymer and a pigment are dispersed and electrodeposited on a patterned electrode on a substrate. The printing method is a method in which three primary colors of RGB ink are printed using a printing machine. The micellar electrolysis method is a method in which a pigment is dispersed using a surfactant to form a dye layer on an electrode patterned on a substrate. Among these, in the dyeing method, the pigment dispersion method, the printing method, etc., in the formation of the red (R), green (G), and blue (B) patterns, the respective positions are accurately aligned with other patterns. It is necessary to perform the alignment, and the alignment between the dye layer and the liquid crystal driving electrode is also required.

On the other hand, in an electrochemical method such as an electrodeposition method or a micelle electrolytic method, when a transparent electrode is patterned,
Although a photolithography method is used, such precise alignment is not required. Furthermore, the micellar electrolysis method allows the formation of a conductive color filter layer, and the dye layer can be used as a liquid crystal drive electrode without laminating the liquid crystal drive electrode on the dye layer again. For this reason, the micelle electrolysis method has established a basic technology (J. Am. Ch.
em. Soc. Since 1991, 113, 450-456, JP-A-2-146001, JP-A-2-14997, and JP-A-3-102302, various studies have been made toward practical use. In particular, since precise alignment is not required, the present invention is highly adaptable to a plastic film substrate in addition to a normal glass substrate. Plastic films have a thickness of about 0.1 to 0.3 mm and are light in weight, making them ideal for portable devices. Recently, plastic films have been used for portable devices such as mobile phones and electronic organizers. Liquid crystal display devices have come to be used.

When a dye layer is formed by the micellar electrolysis method, a washing step is required in the course of the process. In this case, in the cleaning process, water is used in terms of cost of the cleaning liquid and cost of disposal of the used cleaning liquid, but water droplets adhere to the substrate immediately after the cleaning. The thin film formed by the micellar electrolysis method is formed of pigment particles.If the water droplets adhere to the pigment thin film, the pigment particles are gathered at the site where the water droplets adhere, and the pigment thin film is disturbed. Had occurred. Since the surface tension of water is very large (72.75 mN / m at 20 ° C.) due to the disorder of the pigment thin film, if water droplets adhere to the pigment thin film for a certain period of time, the surface of the water itself will be shrunk. It is considered that this occurs because the pigment particles are involved in the force (surface tension).

Accordingly, in order to prevent the pigment thin film from being disturbed, it is necessary to quickly remove water droplets adhered to the substrate after washing the substrate with water. However, for example, in a process of performing air blowing after water washing, since water drops are removed by physical force, if the air blowing is too strong,
There is a possibility that the pigment thin film may be blown off. In this case, the air blow causes the pigment thin film to be disturbed. In order to solve the above-mentioned problem, Japanese Patent Application Laid-Open No. 4-63304 discloses a method of defining a pulling speed from a water washing tank. This reduces the lifting speed (5 mm / s
ec), a method of making it difficult for droplets to adhere to the substrate surface. However, in this method, the pulling speed is slow, so that the time of the cleaning step is increased, which increases the manufacturing cost in the production step. In addition, when the substrate has flexibility such as a resin film, water droplets may adhere to the substrate surface even if the lifting speed is reduced due to poor flatness, and in this case, the same applies to the above-described reason. Of the pigment thin film.

[0007]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problem of the water washing step in the method for producing a color filter, and cleans the dye thin film layer of the color filter formed by the pigment particles satisfactorily and in a short time. It provides a method.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a transparent electrode pattern is formed on an insulating transparent substrate, and pigment particles are deposited on the transparent electrode pattern by using an electrochemical method. Forming a color filter, and then washing the dye layer with water, wherein the color filter is further washed with a liquid having a surface tension smaller than water after the water washing. By providing the manufacturing method of the above, the above-mentioned problem could be solved. The type of the liquid A is not particularly limited as long as it is smaller than the surface tension of water. For example, the liquid A may be 50 mN / m or less at 20 ° C.

Hereinafter, the present invention will be specifically described with reference to the drawings. FIG. 1 is an example of a basic color filter manufacturing method of the present invention. The insulating transparent substrate 1 on which the transparent electrode pattern 2 was formed was held by the holding jig 3 (A). The insulating transparent substrate 1 was immersed in the electrolytic solution 4 to form a dye layer (not shown) on the electrode pattern 2 of the substrate 1 (B). Next, the substrate 1 on which the dye layer has been formed is washed with water in a water washing tank 6 (C). FIG. 1 shows an example of washing in running water by flowing water from the bottom of the water washing tank 6 and overflowing water from the upper part of the water washing tank 6, but washing may be performed in still water. By immersing the substrate 1 on which the dye layer (not shown) is formed on the electrode pattern 2 in the liquid A, water droplets on the surface are removed and the surface tension of the liquid A is small. Does not adhere. However, when the substrate is transferred from the water washing tank 6 to the liquid A tank 8, if it is not performed quickly, water droplets adhering to the substrate may disturb the dye layer. The time to transfer this substrate depends on the adhesion of the pigment particles to the substrate,
Although it depends on various factors such as the thickness of the dye layer, it is preferable that the time be 5 seconds or less.

In the present invention, preferably, as shown in FIG. 2, washing with water and immersion in liquid A can be performed in the same tank. That is, as shown in FIG. 2, water flows in from the lower part of the water washing tank 6, while water washing is performed while overflowing water from the upper part of the water washing tank 6, and the inflow of water is stopped to stop the water washing. The liquid A flows from the lower part of the water washing tank 6, and the washing is performed while replacing the water with the liquid A while overflowing. However, the present invention is not limited to the case where the cleaning is performed in the same cleaning tank. The manufacturing method of the embodiment shown in FIG. 2 is particularly effective in the following cases. For example, when the pigment particles forming the pigment layer are hydrophobic and the SP value of the liquid A is small, immersing the substrate in the liquid A may cause the pigment thin film to flow out. At this time, in the case of the embodiment shown in FIG. 2, the pigment thin film is immersed in a mixed solvent of liquid A and water, and the ratio of liquid A to water is set so that the pigment thin film does not flow out. It can be adjusted.

The liquid A used in the above-mentioned embodiment is preferably an organic liquid having a property of being compatible with water to form a uniform solvent. Further, it is desirable that the liquid A has a lower boiling point and a lower vapor pressure than water. In this case, if the liquid A has a lower boiling point and a lower vapor pressure than water, the drying conditions can be the same as in the case of water washing. Specific examples of the liquid A include, for example, ethanol, methanol, n
-Low-boiling alcohols such as propanol and isopropanol, and organic solvents such as acetone and diethyl ketone are used, and ethanol, which is particularly environmentally friendly, is preferred.

[0012]

Embodiments of the present invention will be described below. However, the present invention is not limited to the following examples.

Example 1 A color filter was manufactured according to the process shown in FIG. A PES (polyether sulfone) substrate having a thickness of 150 μm was used as an insulating transparent substrate, and the insulating substrate having a transparent electrode (ITO) formed on the insulating transparent substrate was immersed in an electrolytic solution (pigment dispersion liquid). After performing electrolysis under the conditions and forming a pigment thin film pigment layer on the transparent electrode (ITO), washing with water and a cleaning agent having a surface tension smaller than that of water is performed under the following conditions, and the state of film formation of the obtained pigment thin film is visually observed. Was determined. The results are shown in Table 1 below. Electrolysis conditions: electrolysis potential; 0.5 V (vs Ag / AgC
l), electrolysis time 3 minutes Cleaning condition: immersed in pure water at a flow rate of 30 mm / sec for 120 seconds Liquid A: ethanol; surface tension 22.70 mN / m
(Immersion time 10 seconds) Substrate lifting speed from liquid A 50 mm / sec

Example 2 A color filter was manufactured using the same substrate as in Example 1 according to the process shown in FIG. 2 under the following conditions. Table 1 shows the results. Electrolysis conditions: electrolysis potential; 0.5 V (vs Ag / AgC
l), electrolysis time: 3 minutes Cleaning condition: immersed in pure water at a flow rate of 30 mm / sec for 120 seconds, cleaning tank volume: 1000 cm ³ Liquid A: ethanol at a flow rate of 30 cm ³ / sec.
Flow into cleaning tank for 1 minute (total flow rate 1800 cm ³ ) Substrate lifting speed from liquid A 50 mm / sec

Example 3 Same as Example 1 according to the process shown in FIG. 2 under the following conditions.
A color filter was manufactured using the substrate of No. 1. The result
The results are shown in Table 1. Electrolysis conditions: electrolysis potential; 0.5 V (vsAg / AgC
l), electrolysis time 3 minutes Cleaning condition: 120 seconds in pure water at a flow rate of 30 mm / sec
Immersion, washing tank volume 1000cm^Three  Liquid A: acetone (surface tension 23.70 mN / m)
30cm^Three/ Sec flow into the cleaning tank for 20 seconds
(Total flow 600cm^Three) Substrate lifting speed from liquid A 50 mm / sec

Comparative Example 1 An experiment was performed in the same manner as in Example 1 except that the liquid A was not used (the condition was a pulling speed from the water washing tank). Table 1 shows the results.

COMPARATIVE EXAMPLE 2 The experimental conditions of Example 3 were set to 1 at a flow rate of 30 cm ³ / sec.
The procedure was carried out in the same manner as in Example 3, except that the mixture flowed into the washing tank for a minute (total flow rate 1800 cm ³ ). The results are shown in Table 1.

[0018]

[Table 1] Evaluation: The film formation state is visually judged (five-level evaluation). Rank 5: The film is formed uniformly. Rank 4: The film is formed almost uniformly. Rank 3: The film is formed without practical problems. Rank 2 : Slightly disordered film is seen. Rank 1: Significantly disordered film is seen.

Hereinafter, embodiments of the present invention will be described. 1. An electrode pattern is formed on an insulating substrate, a pigment layer of a color filter is formed by depositing pigment particles on the electrode pattern, and then a method of manufacturing a color filter having at least a step of washing the pigment layer with water. A method for producing a color filter, wherein after the water washing, further washing is performed using a liquid having a surface tension smaller than water. 2. The method for producing a color filter as described in 1 above, wherein the insulating substrate is a transparent substrate. 3. The above-mentioned 1-2, wherein the electrode pattern is a transparent electrode pattern
Method for manufacturing color filters. 4. The method for producing a color filter according to any one of the above 1 to 3, wherein the pigment particles are deposited using an electrochemical technique. 5. The method for producing a color filter according to the above item 4, wherein the electrochemical method is a micelle electrolysis method. 6. The method for producing a color filter according to any one of the above 1 to 5, wherein the water washing and the washing with the liquid A are performed in the same washing tank. 7. The method for producing a color filter according to the above item 6, wherein the washing is performed while replacing the water with the liquid A in the washing tank after the washing with water. 8. The method for producing a color filter according to claim 7, wherein the washing performed while replacing water with the liquid A is performed under stirring. 9. 1 to 8 wherein the liquid A is a liquid having a property of being compatible with water.
Method for manufacturing color filters. 10. 10. A color filter manufactured by using the method for manufacturing a color filter according to any one of 1 to 9 above. 11. A liquid crystal display device using the color filter according to 10 above.

[0020]

According to the present invention, a transparent electrode pattern is formed on an insulating transparent substrate, and pigment particles are deposited on the transparent electrode pattern by an electrochemical method to form a dye layer of a color filter. In a method for manufacturing a color filter having at least a step of washing the layer with water, a method for satisfactorily and quickly washing a dye thin film layer of a color filter formed by pigment particles can be provided.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment (an embodiment in which water washing and liquid A are performed in a separate tank) of the method for producing a color filter of the present invention. (A) Insulating transparent substrate 1 on which transparent electrode pattern 2 is formed
FIG. 6 is a view showing that the holding jig 3 is carried by the holding jig 3. (B) is a view showing a step of forming a dye layer by electrolysis. (C) It is a figure which shows the washing process in running water. (D) is a diagram showing a cleaning step using a liquid A.

FIG. 2 is a diagram showing another embodiment (an embodiment in which water washing and liquid A are performed in the same manner) of the method for producing a color filter of the present invention. (A) is a view showing that an insulating transparent substrate 1 on which a transparent electrode 2 is formed is supported by a holding jig 3. (B) is a view showing a step of forming a dye layer by electrolysis. (C) It is a figure which shows the washing process in running water. (D) is a diagram showing a cleaning step using a liquid A.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating transparent substrate 2 Transparent electrode pattern 3 Holding jig 4 Electrolyte 5 Electrolysis tank 6 Water washing tank 7 Liquid A 8 Liquid A tank

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akihiko Kanemoto 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Company, Ltd.

Claims (5)

[Claims] 1. A color comprising at least a step of forming an electrode pattern on an insulating substrate, forming a pigment layer of a color filter by depositing pigment particles on the electrode pattern, and then washing the pigment layer with water. In the method for producing a filter, a method for producing a color filter, wherein after the water washing, further washing is performed using a liquid having a surface tension smaller than that of water (hereinafter also referred to as liquid A). 2. The method for producing a color filter according to claim 1, wherein the water washing and the washing with the liquid A are performed in the same washing tank. 3. The method for producing a color filter according to claim 1, wherein the liquid A is a liquid having a property of being compatible with water. 4. A color filter manufactured using the method for manufacturing a color filter according to claim 1. 5. A liquid crystal display device using the color filter according to claim 4.