JP2001123295A - Method of manufacturing thin film, and method of manufacturing color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably form a thin film such as a uniform dye stuff layer by a simple treatment. SOLUTION: An electrolytic solution remaining on the surface of an electrode with pigment particles electrodeposited thereon can be prevented from being solidified by electrodepositing a dye stuff layer in a dye stuff layer forming process 2 and then implementing a cleaning process without allowing evaporation of the electrolytic solution remaining on a substrate 5, only the electrolytic solution remaining on the surface of the electrode 4 with the pigment particles electrodeposited thereon and to the surface of the insulating substrate 5 is washed away, the dye stuff layer formed on the electrode is prevented from being peeled off, and the thin film of the excellent dye stuff layer can be stably manufactured.

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 thin film and a method for manufacturing a color filter used in a color liquid crystal display device, and more particularly to a method for manufacturing a color filter for a full color liquid crystal using a plastic film substrate suitable for portable equipment. Things.

[0002]

2. Description of the Related Art Liquid crystal display devices have come to be used in various fields and are becoming more and more important as information display devices. In particular, portable devices are characterized by small size, light weight, low power consumption, color display, and the like, and are therefore used in many devices such as personal computers and video devices. In addition, a technique for colorizing a liquid crystal display device has been advanced, and various methods such as a dyeing method, a pigment dispersion method, an electrodeposition method, a printing method, and a micelle electrolytic method have been properly used as a method for manufacturing a dye layer of a color filter for liquid crystal.

The dyeing method is a method in which an anti-staining film is formed on gelatin by a photolithography method and dyed for each color of RGB with a dye. The pigment dispersion method is a method in which an ultraviolet-curable resist in which a pigment is dispersed is applied to a substrate, and mask exposure and thermal curing by photolithography are repeated three times for R, G, and B to form a dye layer. Since the dyeing method and the pigment dispersion method use a photolithography method, the pattern accuracy is high. The electrodeposition method is a method in which an electrodeposition polymer and a pigment are dispersed in an electrode patterned on a substrate, and the electrodeposition coating is performed. The printing method is a method of printing three primary colors of RGB using a printing machine, and the micellar electrolytic method is a method of forming a pigment layer by dispersing a pigment using a surfactant on a patterned electrode on a substrate using a surfactant. is there. Among these, in the dyeing method, the pigment dispersion method, and the printing method, in forming a red (R), green (G), and blue (B) pattern, each position is accurately aligned with another pattern. There is a need to do. In addition, it is necessary to align the dye layer and the liquid crystal driving electrode.

In the case of an electrochemical method such as an electrodeposition method and a micelle electrolytic method, a photolithography method is used when patterning a transparent electrode, but a precise method such as a dyeing method, a pigment dispersion method and a printing method is used. No alignment is required, and
The micellar electrolysis method can form a conductive color filter layer, and the dye layer can be used as a liquid crystal drive electrode without laminating a liquid crystal drive electrode on the dye layer again. For this reason, the micelle electrolysis method has established a basic technology (J. Am. Chem. Soc. 1991, 1113).
450-456, JP-A-2-146001, JP-A-2-14997, and JP-A-3-102302), various studies have been conducted toward practical use.
In particular, since there is no need for precise positioning, it is highly adaptable to plastic film substrates other than ordinary glass substrates. In recent years, liquid crystal display devices using plastic films have come to be used for portable devices such as mobile phones and electronic organizers. This plastic film has a thickness of about 0.1 to 1 mm and is light in weight, so that it is most suitable for portable equipment.

[0005] In these portable devices, since long-time operation by a battery is required, reduction in the consumption of the liquid crystal display panel has been greatly emphasized. Therefore, a reflective liquid crystal panel that does not use a backlight has been demanded. As one of the technical problems of the reflective liquid crystal panel is to secure brightness, a high visible light transmittance is required for a color filter used in the reflective color liquid crystal panel, and the value is in a wavelength region of 400 nm to 400 nm. 800 nm
The value of the average transmittance in the range of from about 50% to more than that (based on air). One of the methods for increasing the transmittance is to reduce the thickness of a dye layer formed on a transparent electrode.

[0006]

However, when a dye layer is formed on a transparent electrode using an electrochemical method,
A cleaning step is required after the electrodeposition. However, when a dye layer having a thickness of about 0.5 μm or less is to be formed, a problem that the dye layer formed on the electrode in the cleaning step flows down. May occur.

In particular, this problem is caused by the fact that the liquid adhering to the substrate evaporates during the transfer to the cleaning step after the completion of electrodeposition, the surface layer of the dye layer is solidified, and the liquid at the interface with the substrate has not been evaporated yet. It is considered that this occurs because the dye layer is peeled off.

Further, in the case of a color filter for a full-color liquid crystal, it is necessary to make the electrode width smaller than that for a mono-color liquid crystal, and this electrode width is 0.1 mm or less. In this case, the frequency of the dye layer flowing down becomes higher. This development is particularly remarkable when the dye layer is composed of pigment particles. This is because, as shown in FIG. 2A, when the electrodeposited electrode 4 removed from the electrolytic cell and the insulating substrate 5 to which the electrolytic solution 7 is adhered are washed,
As shown in (b), the pigment particles flowing down at the boundary between the electrode 4 and the insulating substrate 5 wash away the pigment in the pigment layer partially electrodeposited on the electrode 4 together. it is conceivable that. When the width of the electrode is small, the ratio of the area of the dye layer flowing down to the entire area of the electrode increases, and the frequency of the flow down of the dye layer increases.

In the case of a color filter for a full-color liquid crystal, since it is necessary to form three color dye layers of R, G, and B, it is necessary to form the same color dye layer at a ratio of one to three. There is. In this case, the frequency of the dye layer flowing down is
For example, it is higher than a case where all electrodes are electrodeposited at once as a monocolor color filter. This is considered to be due to the fact that the pigment particles to be washed away in the washing step are increased in the case of full color, and this is because the pigment layer electrodeposited on the electrode portion is washed away.

As a countermeasure, Japanese Patent Publication No. 6-8516 discloses a method for producing a thin film using a micelle agent comprising a ferrocene derivative in an aqueous solvent using an electrode and a substrate whose surfaces have been subjected to hydrophobic treatment. The micelle solution obtained by solubilization is subjected to an electrolytic treatment to form a thin film of a hydrophobic substance on the electrode. The thin film formed on the electrode is hardly damaged by washing, and the hydrophobic substance attached to the substrate can be easily washed away by washing. However, this method has a disadvantage that the number of manufacturing steps must be increased, such as hydrophobic treatment of the surface of the electrode and the substrate.

It is an object of the present invention to provide a method of manufacturing a thin film, a method of manufacturing a color filter, and a manufacturing apparatus capable of reliably forming a uniform thin film such as a dye layer with a simple process by remedying such disadvantages. It is assumed that.

[0012]

A method of manufacturing a thin film according to the present invention is a method of manufacturing a thin film in which a dye layer is electrochemically laminated on an electrode on an insulating substrate. The cleaning step is performed without evaporating the electrolytic solution attached on the top.

The method of manufacturing a color filter according to the present invention is a method of manufacturing a color filter in which a dye layer of a color filter for a liquid crystal display, which is laminated on a insulating substrate in the order of a transparent electrode and a dye layer, is electrodeposited by micellar electrolysis. The method is characterized in that after the step of electrodepositing the dye layer, a washing step is performed without evaporating the electrolytic solution attached to the substrate.

Further, it is desirable to add a solution or compound which is water-soluble and has a higher boiling point than water and does not form micelles with pigment particles, to the electrolytic solution in the electrolytic cell.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a thin film according to the present invention has a dye layer forming step and a washing step. In the dye layer forming step, the insulating substrate having the transparent electrode held by the holding jig is immersed in an electrolytic tank having an electrolyte solution in which the pigment is dispersed, electrolytically treated, and the pigment particles are electrodeposited on the transparent electrode to form the dye layer. Form. In the washing step, the transparent electrode on which the pigment particles are electrodeposited and the insulating substrate to which the electrolytic solution is attached are taken out of the electrolytic bath and washed in the washing bath.

After the pigment particles are electrodeposited on the transparent electrode in the dye layer forming step, when the insulating substrate is taken out of the electrolytic bath and washed in the washing bath, the process is repeated until the insulating substrate is taken out of the electrolytic bath and washed in the washing bath. During this time, the evaporation of the electrolyte adhering to the transparent electrode on which the pigment particles are electrodeposited and the surface of the insulating substrate is prevented. In order to prevent the electrolytic solution attached to the surface of the transparent electrode and the insulating substrate on which the pigment particles are electrodeposited from evaporating,
For example, after taking out the insulating substrate held by the holding jig from the electrolytic bath, it is quickly put into the cleaning bath. The transparent electrode on which the pigment particles are electrodeposited is cleaned by placing the pigment particles in the cleaning tank and evaporating the electrolyte before the electrolyte attached to the surface of the insulating substrate evaporates. Can prevent the electrolyte solution attached to the surface of the substrate from hardening, and can wash off only the transparent electrode on which the pigment particles are electrodeposited and the electrolyte solution attached to the surface of the insulating substrate in the cleaning tank. The formed dye layer is prevented from being peeled off, and a dye layer having a predetermined width can be formed.

[0017]

Embodiment 1 FIG. 1 is a process chart of an embodiment of the present invention. As shown in the drawing, for example, a method of manufacturing a thin film of a dye layer such as a color filter used for a color liquid crystal display device includes a substrate holding step 1, a dye layer forming step 2, a washing step 3
Having. In the substrate holding step 1, an insulating substrate 5 having a transparent electrode 4 formed by a photolithography method is held by a holding jig 6. In the dye layer forming step 2, the insulating substrate 5 held by the holding jig 6 is coated with an electrolyte 7 in which a pigment is dispersed and an electrode 8.
Is immersed in an electrolytic cell 9 having the above, and subjected to electrolytic treatment to electrodeposit pigment particles on the transparent electrode 4 to form a dye layer. In the washing step 3, the transparent electrode 4 on which the pigment particles are electrodeposited and the insulating substrate 5 to which the electrolytic solution 7 is adhered are taken out of the electrolytic bath 9 and, for example, water 1
Cleaning is performed in running water of a cleaning tank 11 which supplies 0 and overflows from above.

After the pigment particles are electrodeposited on the transparent electrode 4 in the dye layer forming step 2, the insulating substrate 5 is taken out of the electrolytic bath 9 and taken out of the electrolytic bath 9 when the washing is performed in the washing bath 11. Until the washing is performed in the washing tank 11, the electrolyte attached to the surface of the transparent electrode 4 on which the pigment particles are electrodeposited and the insulating substrate 5 is prevented from evaporating. In order to prevent the electrolyte adhered to the surface of the transparent electrode 4 on which the pigment particles were electrodeposited and the insulating substrate 5 from evaporating, the insulating substrate 5 held by the holding jig 6 was taken out from the electrolytic bath 9, for example. Then, it is quickly put into the washing tank 11. For example, when the electrolytic solution 7 in the electrolytic cell 9 is mainly composed of water and electrodeposition is performed at room temperature of about 20 ° C., the insulating substrate 5 is taken out of the electrolytic cell 9 and put into the cleaning tank 11 within a few seconds. Transparent electrode 4 electrodeposited with pigment particles
And the electrolyte attached to the surface of the insulating substrate 5 is prevented from evaporating. Further, when the room temperature is higher than about 20 ° C., or when the main component of the electrolytic solution 7 in the electrolytic bath 9 is made of a substance that evaporates more easily than water, the insulating substrate 5 taken out of the electrolytic bath 9 is cleaned more quickly. 11 to prevent the electrolyte adhered to the surface of the transparent electrode 4 on which the pigment particles are electrodeposited and the insulating substrate 5 from evaporating.

As described above, before the electrolyte adhered to the transparent electrode 4 on which the pigment particles are electrodeposited and the surface of the insulating substrate 5 are evaporated, the electrolyte is put into the washing tank 11 to wash the electrolyte. The electrolyte attached to the surface of the electrodeposited transparent electrode 4 is prevented from solidifying, and only the electrolyte attached to the electrode 4 on which the pigment particles are electrodeposited and the surface of the insulating substrate 5 are washed off in the cleaning tank 11. This makes it possible to form a dye layer having a predetermined width while preventing the dye layer formed on the transparent electrode 4 from being peeled off.

[0020]

Embodiment 2 In the above embodiment, the insulating substrate 5 taken out of the electrolytic bath 9 is put into the cleaning bath 11 more quickly, and the transparent electrode 4 on which the pigment particles are electrodeposited and the electrolysis where the surface of the insulating substrate 5 adheres. The case where the liquid is prevented from evaporating has been described. However, the temperature around the electrolytic bath 9 is lowered, or the electrolytic solution 7 in the electrolytic bath 9 is cooled and the holding jig 6 is taken out from the electrolytic bath 9. By lowering the temperature of the entire insulating substrate 5 held, the transparent electrode 4 on which the pigment particles are electrodeposited, and the electrolytic solution attached to the surface of the insulating substrate 5, the transparent electrode 4 on which the pigment particles are electrodeposited is insulated. The evaporation of the electrolytic solution attached to the surface of the conductive substrate 5 can be prevented. Further, by evaporating the electrolytic solution 7 in the electrolytic bath 9 by lowering the ambient temperature of the electrolytic bath 9 or cooling the electrolytic solution 7 in the electrolytic bath 9 as described above. When the surrounding atmosphere of the electrolytic cell 9 is lowered or the electrolytic solution 7 in the electrolytic cell 9 is cooled, the lower the cooling temperature, the more the evaporation of the electrolytic solution can be prevented. And

Furthermore, when the electrolytic solution 7 in the electrolytic bath 9 contains water, the surrounding atmosphere of the electrolytic bath 9 and the cleaning bath 11 is made to have a high humidity, so that the transparent electrode 4 on which the pigment particles are electrodeposited.
Thus, the evaporation of the electrolytic solution attached to the surface of the insulating substrate 5 can be further prevented.

When a color filter is produced by the micellar electrolysis method, a solution or compound which is water-soluble in an aqueous solution and has a higher boiling point than water and does not form micelles with pigment particles is added to the electrolytic solution 7 in the electrolytic cell 9. By doing so, evaporation of the electrolytic solution can be further suppressed without inhibiting micelle formation between the pigment and the surfactant in the electrolytic solution 7.

Examples of the solution or compound which is water-soluble in an aqueous solution which is an additive of the electrolytic solution 7 and has a higher boiling point than water and does not form micelles with pigment particles include diol compounds such as ethylene glycol, propylene glycol and diethylene glycol. Alternatively, there are derivatives thereof, triol compounds represented by glycerin, and derivatives thereof. Compounds that form micelles with pigment particles, such as polyethylene glycol, are not suitable as additives for the electrolyte 7. However, when the derivative of these additives has a group contributing to the oxidation-reduction reaction, such as a surfactant in the micelle electrolyte, for example, ferrocene in the molecule, the additives themselves contribute to the micelle electrolysis reaction. This is not the case.

[Specific Example 1] A 150 μm thick PES (polyether sulfone) was used as the insulating substrate 5, and the temperature of the electrolytic solution 7 in the electrolytic cell 9 was set to 20 ° C. in an atmosphere at a room temperature of 20 ° C. Pigment particles are electrodeposited on the transparent electrode 4 in an electrolysis time of 2 minutes, the insulating substrate 5 is lifted out of the electrolysis tank 9 and immersed in the cleaning tank 11 in 3 seconds, and washed in pure water at a flow rate of 30 mm / sec for 120 seconds. Thus, a thin film of a dye layer was formed.

[Specific Example 2] In the specific example 1, the electrolytic cell 9
A thin film of a dye layer was formed on the insulating substrate 5 under the same conditions as in Example 1 except that 8% by weight of ethylene glycol was added to the electrolytic solution.

[Comparative Example] In Example 1, the insulating substrate 5 was immersed in the cleaning tank 11 10 seconds after being lifted from the electrolytic bath 9, and the other conditions were the same as those in Example 1. Then, a thin film of a dye layer was formed.

The states of the thin films formed in the specific examples 1, 2 and the comparative example were visually determined, and the results of the evaluation on a scale of 1 to 5 are shown in the following table. In the evaluations in the following table, rank 5 indicates that the film was formed uniformly, rank 4 if the film was formed almost uniformly, and rank 3 if the film was formed without practical problems. Was evaluated as rank 2, and the case where the film was considerably disturbed was evaluated as rank 1.

[0028]

[Table 1]

As shown in the above evaluation results, the insulating substrate 5
Was lifted out of the electrolytic bath 9 and washed before the electrolytic solution adhering to the surface of the transparent electrode 4 on which the pigment particles were electrodeposited and the insulating substrate 5 was evaporated, whereby a good quality thin film could be formed. In addition, as shown in the comparative example, 10 seconds after the insulating substrate 5 was pulled out of the electrolytic cell 9, the transparent electrode 4 on which the pigment particles were electrodeposited and the electrolytic solution adhering to the surface of the insulating substrate 5 were removed. In the case of washing after evaporation, the formed thin film was considerably disturbed, and it was confirmed that a high quality thin film could be formed by preventing the evaporation of the electrolytic solution.

[0030]

As described above, according to the present invention, after the electrodeposition step of the pigment layer, the cleaning step is performed without evaporating the electrolytic solution adhering to the substrate, whereby the electrode on which the pigment particles are electrodeposited is formed. The electrolyte attached to the surface can be prevented from hardening, and only the electrode on which the pigment particles are electrodeposited and the electrolyte attached to the surface of the insulating substrate are washed away, and the dye layer formed on the electrode is peeled off That is to say, it is possible to stably produce a high quality dye layer thin film.

Further, when water is contained in the electrolytic solution,
By setting the temperature of the substrate immediately after the electrodeposition to be lower than the temperature of the surrounding atmosphere of the electrolytic cell, it is possible to clean the substrate by a simple process without evaporating the electrolytic solution attached to the substrate.

When a color filter is manufactured by electrodepositing a dye layer of a color filter for a liquid crystal display by a micellar electrolysis method, after the step of electrodepositing the dye layer, washing is performed without evaporating the electrolytic solution attached to the substrate. By performing the process,
The pigment particles are electrodeposited on the electrode and only the electrolyte attached to the surface of the insulating substrate can be washed away to prevent the dye layer formed on the electrode from being peeled off. A color filter can be manufactured stably.

Further, by adding a solution or compound which is water-soluble and has a boiling point higher than that of water and does not form micelles with the pigment particles, the pigment and the surfactant in the electrolyte solution are added to the electrolyte solution used in the micelle electrolysis method. The evaporation of the electrolytic solution can be further suppressed without hindering the formation of micelles, and a color filter having a high quality dye layer thin film can be manufactured more stably.

[Brief description of the drawings]

FIG. 1 is a process chart of an embodiment of the present invention.

FIG. 2 is an explanatory view showing a state where an electrode portion from which pigment particles flow down is shown.

[Explanation of symbols]

1; substrate holding step, 2; dye layer forming step, 3; washing step, 4; transparent electrode, 5; insulating substrate, 6; holding jig,
9; electrolytic bath, 11; washing bath.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 342 G09F 9/00 342Z 9/30 349 9/30 349B F-term (Reference) 2H048 BA02 BA62 BB02 BB15 BB43 2H091 FA02X FA02Y FA02Z FC06 FC24 LA02 LA12 5C094 AA03 AA08 AA42 AA43 BA43 CA19 CA24 DA13 EA04 EA05 EB02 ED03 FA01 FB01 GB10 5G435 AA04 AA17 BB12 CC12 FF14 GG12 KK07

Claims (3)

[Claims] In a method of electrochemically laminating a dye layer on an electrode on an insulating substrate, after the electrodeposition step of the dye layer, a washing step is carried out without evaporating an electrolytic solution attached to the substrate. A method for producing a thin film. 2. A method for producing a color filter, wherein a dye layer of a color filter for a liquid crystal display, which is laminated on a insulating substrate in the order of a transparent electrode and a dye layer, is electrodeposited by micellar electrolysis. Thereafter, a washing step is performed without evaporating the electrolyte adhering to the substrate, thereby producing a color filter. 3. The method for producing a color filter according to claim 2, wherein a solution or compound that is water-soluble and has a higher boiling point than water and does not form micelles with pigment particles is added to the electrolytic solution in the electrolytic cell.