JPH11326628A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a conductive color filter having a light shielding layer by a black matrix, without executing precision alignment. SOLUTION: This process for producing a color filter forms the color filter comprises the steps in which a substrate having patterned transparent conductive thin films is immersed into a dispersion of dyestuffs of three primary colors formed by subjecting the dyestuffs having spectral characteristics of three primary colors red, green and blue, respectively to micelle formation by using a surfactant having a section electrochemically oxidizable and/or reduction in an aqueous medium, for example, a ferrocene derivative surfactant, and is then subjected to an energization treatment, by which the dyestuff films of the three primary colors described above are formed on the transparent electrodes and thereafter, a UV absorbent is incorporated into an least one kind of the dyestuff film among the dyestuff films. A black photosensitive resin composition is then applied thereon. Next, the dyestuff films are exposed from the rear surface of the substrate, by which the light shielding layers are formed between the respective dyestuff films.

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 for a color liquid crystal display device, and more particularly to a method for manufacturing a color filter suitable for a plastic film substrate having excellent portability.

[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 been advanced, and as a method of manufacturing a color filter for liquid crystal, a dyeing method, a pigment dispersion method, an electrodeposition method,
Various methods such as a printing method and a micellar electrolytic method have been proposed, and some of them have been put to practical use. The dyeing method is a method of forming an anti-staining film on gelatin by a photolithography method and dyeing each of RGB colors with a dye. The pigment dispersing method is to apply an ultraviolet-curable resist in which a pigment is dispersed to a substrate. Is a method of forming a dye layer by repeating mask exposure and heat curing by photolithography three times RGB to form a dye layer. The electrodeposition method is a method in which an electrodeposition polymer and a pigment are dispersed, and an electrode patterned on a substrate is electrodeposited. The printing method is a method of printing inks of three primary colors of RGB using a printing machine, and the micellar electrolytic method is a method in which a pigment is dispersed using a surfactant to form a patterned electrode on a substrate. This is a method of forming a dye layer on the substrate. Among these, in the dyeing method, the pigment dispersion method, the printing method, and the like, red (R), green (G), blue (B), a light-shielding layer provided to prevent light leakage and enhance contrast, and black (BK) In the pattern formation of
Each position must be accurately aligned with another pattern. For example, a black pattern is formed first, and the red, green, and blue patterns are formed while being precisely aligned with the black pattern. In addition, it is necessary to align the color filter pattern with the electrode for driving the liquid crystal.

In this respect, in an electrochemical method such as an electrodeposition method or a micelle electrolytic method, a photolithography method is used to pattern a transparent electrode, but such precise alignment is not required. Further, the micelle electrolysis method can form a conductive color filter layer, and can use the color filter layer as a liquid crystal drive electrode without laminating a liquid crystal drive electrode again on the color filter layer. For this reason, the micelle electrolysis method has established a basic technique (J. Am. Chem. Soc. 1991, 113,
450-456, Japanese Patent Publication 3-59998, Japanese Patent Publication 7-6
2275, JP-A-2-146001, JP-A-2-149
697, Japanese Patent Application Laid-Open No. 2-267268), various studies have been made toward practical use. In particular, since precise alignment is not required, besides a normal glass substrate,
High adaptability to plastic film substrates.

Recently, a liquid crystal display device using a plastic film has been used for portable equipment such as a mobile phone and an electronic organizer. The plastic film has a thickness of about 0.1 to 0.3 mm and is light in weight, so that it is most suitable for portable equipment. However, it is difficult to form a color filter due to the difficulty of fine patterning on the film substrate and the subtle changes in the dimensions of the substrate depending on the environment such as temperature and humidity. However, the number of colors that can be displayed is limited, and the display colors are not vivid. Further, in this method, since the distance between two substrates (cell gap) needs to be strictly controlled, colorization has not yet been put to practical use in a plastic film liquid crystal display device in which it is difficult to control the distance between substrates.

For this reason, the micellar electrolysis method is promising as a method for producing a color filter on a film substrate.
When forming the light-shielding layer between each of the color filters described above,
It has been a problem until now because precise alignment is difficult. This problem is not preferable not only for a film substrate but also for a substrate such as a glass substrate, which can be precisely positioned, because an increase in the number of times causes an error. For this reason, a method of forming a black light-shielding layer between the color filters by applying a black photosensitive resin composition over the entire surface of the color filter, exposing from the non-coated surface, and developing the so-called back exposure method is known. Proposed (Japanese Unexamined Patent Application Publication No.
-13530, JP-A-1-293306). However, only the method of using the color filter as a photomask in this manner cannot completely cut off the ultraviolet light from the color filter layer, so that a residual film remains on the color filter or a light-shielding layer having a desired thickness is formed. Because it could not be flattened or could not obtain sufficient optical density
Improvements have been attempted, for example, by including an ultraviolet absorbing substance in a pigment-dispersed color filter (JP-A-2-7701).
4, JP-A-9-127325). However, in the case of the pigment dispersion method, since it hinders the curing of the color filter itself,
At present, the above problems have not been solved because the type and content of the ultraviolet absorbing substance are limited.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a conductive color filter having a black matrix light-shielding layer without performing precise alignment.

[0007]

SUMMARY OF THE INVENTION The present invention relates to a surfactant having a site capable of electrochemically oxidizing and / or reducing each of dyes having red, green and blue primary spectral characteristics in an aqueous medium, for example, A substrate having a patterned transparent conductive film is immersed in a dispersion liquid of the three primary colors formed into micelles using a ferrocene derivative surfactant, and the three primary colors of the dye film are formed on the transparent electrode by applying an electric current. Then, after including an ultraviolet absorber in at least one kind of the dye film, a black photosensitive resin composition is applied, and then exposed from the back of the substrate to form a light-shielding layer between the dye films. By providing a method for producing a color filter, the above-mentioned problem can be solved.

In the present invention, as a method of incorporating an ultraviolet absorber in the dye film, the ultraviolet absorber is electrochemically oxidized and / or electrochemically in an aqueous medium in the same manner as the dye.
Alternatively, the dye film is immersed in a micellarized dispersion liquid using a surfactant having a reducible site, for example, a ferrocene derivative surfactant, and a method of applying a current to the dye film to be contained is used. Dissolve or disperse, after coating and drying on the substrate on which the dye film is formed, wash the ultraviolet absorber adhering to unnecessary portions with a solubilizing solvent of the ultraviolet absorber, or a dispersion solvent or the like. The removal method is preferred. The former is particularly difficult to form a film on a transparent electrode if it is an organic ultraviolet absorber, but is easily retained in a porous dye layer formed by micellar electrolysis. Also,
The latter is a method in which an ultraviolet absorber is retained in a dye layer, and then the ultraviolet absorber attached to other unnecessary parts is removed.

As the ultraviolet absorber used in the present invention, an organic ultraviolet absorber having excellent retention in micellar electrolytic CF is particularly effective. The organic ultraviolet absorber is preferably at least one selected from the group consisting of benzotriazole-based compounds, hydroxybenzophenone-based compounds, and salicylate-based compounds. Further, the present invention is most effective when the substrate having the patterned transparent conductive thin film is a plastic film substrate.

Hereinafter, embodiments of the present invention will be described. 1. Micellar electrolysis method The micellar electrolysis method for forming the RGB dye film constituting the color filter of the present invention will be described. First, pigments having RGB spectral characteristics include organic pigments such as perylene pigments, lake pigments, azo pigments, quinacridone pigments, anthraquinone-based, metal-substituted phthalocyanine-based pigments, halogen polysubstituted phthalocyanine-based pigments, titanium oxide, and oxidized pigments. Inorganic pigments such as iron, cobalt violet, and cobalt blue may be mentioned, and these may be used alone or in combination. Further, yellow pigments such as isoindolinone pigments and disazo pigments for adjusting chromaticity, and purple pigments such as dioxane pigments are used as necessary. The particle size of these pigments is 10 μm
The thickness is particularly preferably 1 μm or less. In order to impart conductivity to the prepared dye layer, transparent conductive particles such as ITO are added as necessary in addition to these dyes. Ferrocene derivative surfactants used for converting these hydrophobic substances into micelles are described in JP-A-63-243298 and JP-A-Hei.
226894, JP-A-1-45370, JP-A-2-8
8387, JP-A-2-96585, JP-A-2-2508
92, it is not particularly limited as long as it has both a ferrocene site required for an electrolytic reaction and a nonionic, cationic, or anionic surface active site. The aqueous medium of the micelle electrolyte includes water,
Alcohol, acetone, and the like are mixed and used as necessary. In addition, a supporting electrolyte is added to the micelle electrolyte as needed in order to adjust the electric conductivity of the aqueous medium. Examples of the supporting electrolyte include alkali metal, alkaline earth metal, sulfates, halides, acetates, and the like.
What is generally used widely, such as a water-soluble oxide, is used.

In order to prepare a micelle electrolyte using the above materials, a dye, a surfactant having an electrochemically oxidizable and / or reducible site in the aqueous medium, for example, a ferrocene derivative surfactant If necessary, conductive particles, a supporting electrolyte, and the like are added, and the mixture is uniformly dispersed or solubilized by a dispersion method such as a homogenizer, a three-roll mill, a sand mill, a pearl mill, or a stirrer. Here, when a ferrocene derivative surfactant is used as the surfactant, its concentration is 0.1 mmol / 1 to 1.0.
mol / l is preferable, and the dye concentration is preferably 1 to 500 g / l. In order to prepare a dye thin film using the micelle electrolyte solution prepared in this manner, a conductive substrate is immersed in the electrolyte solution and is subjected to an electric current treatment. The electrolysis conditions at this time include oxidation and reduction of the surfactant. It is performed at a voltage higher than the potential and lower than the hydrogen generation potential. Specifically, the current density is preferably 0.1 to 1.5 V, and the current density is preferably 1 mA / cm ² or less. When electrolysis is performed under such conditions, a desired dye thin film is formed according to the principle of the micelle electrolysis method. After forming the thin film, wash and dry as necessary.
A protective layer may be provided. The protective layer is required to improve the mechanical strength of the dye layer without affecting the driving of the liquid crystal, and to be effective as a blocking layer between the dye layer and the liquid crystal layer. A transparent, light-curable resist cured product such as a resin, an ester, a polyimide, a cyclized rubber, a siloxane, or an epoxy resin, a cured transparent thermosetting resin, or the like is used. In addition, the conductive substrate must be a metal or a conductor that is nobler than the oxidation-reduction potential of the ferrocene derivative surfactant. Gold, platinum, silver, glassy carbon, conductive metal oxide, organic polymer Although a conductor or the like can be used, for use in a liquid crystal cell, a form in which a transparent conductive metal oxide layer such as ITO is formed on glass or a film is preferable, and in the present invention, precise alignment is required. Since an ITO thin film is formed on a plastic film substrate, it is particularly effective.

In the present invention, a light-shielding layer between the respective dyes is prepared by adding a black photosensitive resin composition to the dye film formed as described above, then applying a black photosensitive resin composition, and exposing from the back surface. When a high-contrast color filter having a light-shielding layer with a high optical density is produced, it is important to include an ultraviolet absorber in the dye layer. It is preferable to use a porosity of the micelle electrolytic thin film and hold the ultraviolet absorbent on the dye film after forming the dye film, rather than including the absorbent. As these methods, for example, the dye film is immersed in a micellarized dispersion using a ferrocene derivative surfactant in an aqueous medium in the same manner as the above-described dye,
A method of applying a current to the dye film to be contained, dissolving or dispersing an ultraviolet absorber in a solvent, or spin coating, dipping, spraying or the like on a substrate on which the dye film has been formed, followed by drying by a general method such as spraying. Thereafter, a method of removing the ultraviolet absorber adhering to an unnecessary part by washing with a solvent for dissolving the ultraviolet absorber or a dispersing solvent may be used. In this case, the former is difficult to form a film on the transparent electrode particularly when it is an organic ultraviolet absorber, but is easily retained in the porous dye layer formed by the micellar electrolysis method. Also, when the latter holds the ultraviolet absorber in the dye layer, even if they are washed with a solubilizing solvent or a dispersion solvent, they are not easily eluted,
If the washing conditions are selected, it is possible to wash away only the ultraviolet absorber adhering to other unnecessary parts.
At this time, the solvent to be used is not particularly limited as long as it can easily dissolve or disperse the ultraviolet absorber and can be applied to various general coatings. For example, acetone, methyl ethyl ketone, methyl isobutyl ketone, Ethylene glycol, methylene glycol, propylene glycol, pyrrolidone, dimethylformamide,
Examples include dioxane, tetrahydrofuran, toluene, xylene and the like.

As the ultraviolet absorber used in the present invention, transparent ceramic fine particles such as titanium oxide, tin oxide and cerium oxide, or, in the present invention, particularly effective in the case of an organic ultraviolet absorber, benzotriazole It is preferable to contain at least one selected from the group consisting of a hydroxy compound, a hydroxybenzophenone compound and a salicylate compound. The general formulas of these organic ultraviolet absorbers are shown in the following (I) to (III).

(I) Benzotriazole compounds

Embedded image (R ₁ and R ₂ may be the same or different and each represents, for example, a hydrogen atom or a substituted or unsubstituted alkyl group, alkenyl group, allyl group, aryl group, etc.) (II) Hydroxybenzophenone-based compound

Embedded image (R ₁ and R ₂ may be the same or different, and for example, each may be a substituted or unsubstituted alkyl group, alkenyl group,
Represents an allyl group, an aryl group, or the like. (III) Salicylate compounds

Embedded image (R ₁ and R ₂ each represent a substituted or unsubstituted alkyl group, alkenyl group, allyl group, aryl group, etc.) Hereinafter, specific examples of the above formulas (A) to (C) will be shown.

[0015]

Embedded image

[0016]

Embedded image

[0017]

Embedded image

The content of the ultraviolet absorber in the dye layer is preferably 0.1 to 10%. The light-shielding layer is formed by back exposure between the color filters produced as described above. The light-shielding layer is obtained by photo-curing a black photosensitive resin composition, and the composition contains a black pigment, a binder resin, a photosensitive resin composition, and the like. As black pigments, carbon, aniline black, cyanine black,
A mixture of the R, G, and B pigments and the like are used. As the photosensitive resin composition, (1) a polymer and a photo-crosslinking agent, (2)
Examples include a combination of a monomer or oligomer, a binder resin, and a photopolymerization initiator. Examples of the photocrosslinking agent (1) include diazo compounds, dichromates, chromates, and bisazide compounds. Examples of polymers include 2-hydroxyethyl methacrylate, methoxymethyl acrylamide, dimethylaminopropyl methacrylamide, and methyl methacrylate. And polymers such as acrylic acid.
Examples of the monomer and oligomer of (2) include acrylic acid, 2-hydroxyethyl acrylate, acrylamide, styrene, and vinyl acetate. As the photopolymerization initiator, 4- (2-hydroxyethoxy) phenyl-
(2-hydroxy-2-propyl) ketone, azobisisobutyronitrile, anthraquinone and the like. A black resin composition is prepared using such a material, applied to the entire surface of the dye layer on the substrate, baked and then cured by irradiating light of a photosensitive wavelength from the back side of the substrate (the side without the dye layer). Let it. Here, the light used is general ultraviolet light (300 to 380 n).
m), an excimer laser (157 to 351 nm) and the like. Here, since the dye layer is provided with ultraviolet absorption by the dye and the ultraviolet absorber, the black coating film on the dye layer is not cured, and the black coating film formed on portions other than the dye layer Is cured and the thickness of the photocured light-shielding layer can be made the same as that of the dye layer by adjusting the conditions such as the irradiation amount.

[0019]

Embodiments of the present invention will be described below.

Example 1 A transparent conductive film on a glass substrate was formed with a pitch of 110 μm and a width of 90 μm.
960 μm stripes were processed by the usual photolithography method. Next, a micelle electrolyte was prepared as follows. That is, in the case of red, perylene red 10.0
g, ITO powder 10.0 g, ferrocenyl polyethylene glycol (FPEG, manufactured by Dojindo Chemical Co., Ltd.) 2.5 g as a ferrocene derivative, LiBr 10.4 g as a supporting salt were added to 1000 ml of water, ultrasonically dispersed, and then centrifuged (200
0 rpm 10 minutes), in the case of green, 10.0 g of phthalocyanine green, 10.0 g of ITO powder, FPEG
3.0 g and 10.4 g of LiBr were added to 1000 ml of water, ultrasonically dispersed, and then centrifuged (2000 rpm for 10 minutes). In the case of blue, phthalocyanine blue 1 was added.
0.0 g, ITO powder 10.0 g, FPEG 3.5 g,
After adding 10.4 g of LiBr to 1000 ml of water and ultrasonic dispersion, each was prepared by centrifugation (2000 rpm for 10 minutes). After immersing the glass substrate in the red electrolyte solution prepared in this way, a constant potential electrolysis of 0.5 V is applied to every third transparent electrode for 12 minutes, and a red conductive color is applied on the selected electrode. A filter layer was formed. Subsequently, the substrate was washed with pure water and dried at 120 ° C. Similarly, for 15 minutes with the green electrolyte, 12 minutes with the blue electrolyte,
Electrolysis was performed to form red, green, and blue conductive color filter layers. Next, 7.0 g of 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, FPEG
1.0 g of LiBr and 10.4 g of LiBr were added to 1000 ml of water, ultrasonically dispersed, stirred for 1 day, and insoluble components were removed by centrifugation (2000 rpm for 1 hour) to prepare a benzotriazole micelle electrolyte. The above prepared color filter layer was immersed in the solution, subjected to a constant potential electrolysis of 0.5 V for 5 minutes, washed with pure water and dried to hold the ultraviolet absorbent in the color filter. A black light-curable resin (Fuji Hunt Electronics Technology color mosaic CK-2000) of about 2 μm
Was applied by spin coating, and the entire surface was exposed (300 mJ / cm ² ) from the back side of the substrate with an ultra-high pressure mercury lamp. Development processing was performed with an aqueous alkaline solution (10-fold dilution of a color mosaic CD manufactured by Fuji Hunt Electronics Technology) to form a black matrix between the transparent electrode patterns. Next, after the black matrix was cured by post-baking at 180 ° C., the pigment on the transparent electrode was removed by ultrasonic cleaning. Subsequently, an overcoat layer 0.3 μm made of a thermosetting acrylic resin was formed. Near the peak top of the color filter produced as described above (R: 630 nm, G: 530 nm, B: 470 nm)
Table 1 shows the measured values of the spectral transmittance and the optical density.

Example 2 A 0.2 μm-thick chromium metal film was formed on a transparent conductive film of a transparent conductive film FST-5340 (manufactured by Sumitomo Bakelite Co., Ltd.) by a vacuum evaporation method. Subsequently, 960 stripe-shaped resist patterns having a pitch of 110 μm and a width of 90 μm were formed by a normal photolithography method, and chromium and a transparent conductive film were processed by wet etching with the resist patterns. After removing the photoresist, an RGB conductive color filter was formed on the transparent electrode in the same manner as in Example 1. Next, 5.0 g of 2-hydroxymethoxybenzophenone, 0.5 g of FPEG, 10 g of LiBr.
4 g was added to 1000 ml of water, ultrasonically dispersed, stirred for 1 day, and insoluble components were removed by centrifugation (2000 rpm for 1 hour) to prepare a micelle electrolyte. The color filter layer prepared above was immersed in this,
A constant potential electrolysis of 5 V was performed for 5 minutes, washed with pure water and dried to hold an ultraviolet absorber in the color filter. Hereinafter, in the same manner as in Example 1, a black matrix was formed by back exposure using a black photocurable resin, and the evaluation was performed.

Example 3 In the same manner as in Example 2, RGB was formed on a transparent conductive film.
A conductive color filter was formed. Next, 1.0 g of phenyl salicylate was dissolved in 100 ml of toluene / methyl ethyl ketone (1/1 vol), immersion-coated on the above-prepared color filter layer, dried, shower-washed with toluene, and dried to form a color filter. The UV absorber was retained. Hereinafter, in the same manner as in Example 1, a black matrix was formed by back exposure using a black photocurable resin, and the evaluation was performed.

Comparative Example 1 The procedure was the same as in Example 1, except that the color filter did not contain 2- (2'-hydroxy-5'-methylphenyl) benzotriazole as an ultraviolet absorber.

Comparative Example 2 The same procedure as in Example 2 was carried out except that the ultraviolet absorbent, 2-hydroxymethoxybenzophenone, was not contained in the color filter.

COMPARATIVE EXAMPLE 3 In Example 2, the ultraviolet light absorber 2-hydroxymethoxybenzophenone was not contained in the color filter, and the light exposure for curing the black photocurable resin was 100.
The same applies except that mJ / cm ² was used.

[0026]

[Table 1]

Example 4 A liquid crystal alignment film AL3046 manufactured by Nippon Synthetic Rubber Co., Ltd. was coated on the plastic color filter substrate prepared in Example 2 by 0.1 μm.
After applying m, the alignment treatment is performed by rubbing, and 240
An STN mode liquid crystal cell having a twist angle of 240 degrees and a cell gap of 7 μm was manufactured by laminating the counter substrate having the stripe electrodes. After a circuit for driving liquid crystal was connected to this cell, the cell was sandwiched between a retardation plate and a polarizing plate for color compensation, and when a color liquid crystal display device was completed, good color display could be performed.

[0028]

According to the present invention, it is possible to provide a method of manufacturing a color filter having a light-shielding layer of a black matrix having a sufficient optical density without requiring precise alignment. The organic ultraviolet absorber has excellent retention in a micelle electrolytic color filter, and the micelle electrolytic color filter containing the same does not deteriorate the color characteristics as a color filter, and a photomask at the time of back exposure. Worked as effectively.

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

Claims (4)

[Claims] 1. The three primary colors obtained by micellizing dyes having spectral characteristics of three primary colors of red, green and blue using a surfactant having a site capable of being oxidized and / or reduced electrochemically in an aqueous medium. In the dispersion of the dye, after immersing the substrate having a patterned transparent conductive thin film, after forming the three primary color dye film on the transparent electrode by conducting the current,
After including an ultraviolet absorber in at least one type of dye film of the dye film, a black photosensitive resin composition is applied,
Next, a light-shielding layer is formed between each dye film by exposing from the back surface of the substrate. 2. A method of incorporating an ultraviolet absorber in a dye film, comprising the steps of: using an ultraviolet absorber formed into micelles using a surfactant having a site capable of being electrochemically oxidized and / or reduced in an aqueous medium. The method for producing a color filter according to claim 1, wherein the dye film is immersed in the contained dispersion liquid, and the dye film to be contained is subjected to an electric current treatment. 3. A method of incorporating an ultraviolet absorber in a dye film, wherein a solution or a dispersion of the ultraviolet absorber is applied to a substrate on which the dye film is formed, dried, and then adhered to an unnecessary portion. The method for producing a color filter according to claim 1, wherein the agent is removed by washing with a solvent capable of dissolving or dispersing the ultraviolet absorber. 4. The ultraviolet absorber at least one selected from the group consisting of a benzotriazole compound, a hydroxybenzophenone compound and a salicylate compound.
The method for producing a color filter according to claim 1, wherein the color filter contains a kind.