JPH07306311A - Substrate provided with color filter and liquid crystal display element using the substrate - Google Patents

Abstract

PURPOSE:To form three colors at the same time, to produce the substrate with a small-scale device and to prevent the lowering of the strength of the porous film by making a transparent sealant or its precursor soluble in oil. CONSTITUTION:A light-shielding layer 2 is formed, as required, on a substrate 1, then a colored layer 3 and a sealing layer 4 are provided, and further an electrode layer 6 is furnished, if necessary, through a protective layer 5. The sealent or its precursor is made soluble in oil. Namely, an oil-soluble, especially hydrophobic, material is preferably used to form the sealing layer 4, and a material consisting essentially of polyepoxide or silicone is exemplified. Further, a monoepoxy represented by bisphenol A, bisphenol F, phenol novolac, cresol novolac, etc., the monoepoxy joined with various functional groups and halogenated, the various functional monomer or oligomer having an epoxy group as the functional group, etc., are used as the polyepoxide precursor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate with a color filter and a liquid crystal display device using the same.

[0002]

2. Description of the Related Art In recent years, a color filter has attracted attention as a device for enabling color display of a liquid crystal display device. This is generally a colored layer of three primary colors of red, blue and green formed on a transparent substrate such as glass in a specific pattern such as a stripe pattern.

Conventionally, various methods such as an electrodeposition method, a dyeing method and a pigment dispersion method have been used as a method for forming the colored layer. However, these methods require a photolithography process or the like to form the colored layer, and the number of processes is large. In addition, a complicated line and a large-scale device are required, which causes a decrease in yield and an increase in cost.

[0004]

By the way, Japanese Patent Laid-Open No. 3-116002 proposes a color filter in which a porous layer made of a mixture of pseudo-boehmite sol and a binder resin is dyed with an ink jet. The dyeing layer formed by this composition utilizes the fact that the pseudo-boehmite sol is likely to be positively charged, so that the dye is adsorbed to the dyeing layer by the electrostatic force between the pseudo-boehmite sol and the acidic dye. This color filter can be formed by a relatively small-sized device, and the number of expected manufacturing steps is small.

A color filter dyeing a porous film has been proposed in the past, but one of the advantages of this method over such a proposal is that it can be formed at a low temperature. In the past, it was necessary to bake alumina sol or the like at a high temperature of about 500 ° C. to form a porous film. On the other hand, in the method proposed in the above publication,
Since a porous layer made of a mixture of pseudo-boehmite sol and a binder resin is used, firing is basically unnecessary, and even if firing is performed, low temperature firing is sufficient. Therefore, since there is no problem such as warpage of the substrate during firing, it becomes a very suitable color filter substrate for a liquid crystal display device. In addition, there is a great advantage that a plastic substrate can be used as the substrate.

Further, there is also an advantage that the strength of the porous film against bending of the substrate is high. In the conventional method for producing a porous film, since there is no binder, the porous film may be chipped and spilled when the substrate is bent. Even if glass having a relatively high rigidity is used as the substrate material, the amount of deflection becomes very large as the display becomes large, and this drawback is serious. In the method proposed in the above publication, since the pseudo-boehmite sol is bound by the binder resin,
The porous film hardly spills when the substrate bends.

As described above, the above-mentioned color filter is promising for liquid crystal displays, but it is insufficient as the inventors proceed with research to apply this color filter as a color filter for liquid crystal display elements. It was found that there were points.

When a color filter is used in a liquid crystal display device, a color filter layer is usually provided on the inner surface (liquid crystal layer side) of the substrate in order to minimize parallax. On this occasion,
It is preferable to seal the porous layer after coloring it. This is because the haze is reduced and a clear liquid crystal display is obtained by sealing.

The sealing is generally performed by applying an organic resin, but it has been found that the strength of the porous layer may be deteriorated at this time. If such a decrease in strength occurs, the accuracy of the color filter may be reduced, and eventually the display quality may be deteriorated.

The present invention has been made in order to solve the above problems, and in a color filter of a method of dyeing the inside of a porous film, a color pattern has good accuracy and a clear color image can be obtained. An object is to provide a substrate with such a color filter.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, in which a porous layer formed of inorganic particles and a water-soluble binder resin on a substrate is patterned with a coloring agent. A substrate with a color filter having a colored layer formed by: and a transparent sealing material layer for sealing a porous layer, wherein the transparent sealing material or a precursor thereof is oil-soluble. A substrate with a color filter is provided.

In particular, one of the present invention is further characterized in that the sealing material is an organic resin containing polyepoxide or silicone as a main component.

Further, one of the present invention is further characterized in that the colorant is a water-soluble dye.

Further, one of the present invention is further characterized in that the inorganic particles are pseudo-boehmite sols.

The present invention also provides a liquid crystal display device characterized by using the above-mentioned substrate with a color filter as at least one substrate.

FIG. 1 is a sectional view showing the basic structure of a liquid crystal display panel using the color filter of the present invention. After providing the light shielding layer 2 on the substrate 1 as needed, the colored layer 3 and the sealing layer 4 are provided. Further, an electrode layer 6 is provided via a protective layer 5 if necessary.

In the present invention, the colored layer 3 is formed by pattern-coloring a porous layer composed of inorganic particles and a water-soluble binder resin with a coloring agent, and the sealing material or its precursor is oil-soluble. Characterize. Thus
Prevents deterioration of the strength of the porous membrane due to the sealing treatment,
As a result, an accurate substrate with a color filter can be obtained.

Each component will be described in detail below.

As the material of the substrate 1, glass, quartz, plastic or the like can be used. Examples of the plastic material include polyethylene terephthalate, polyether sulfide, acrylic, polycarbonate, polyimide and the like. Of course, it is not limited to these as long as they do not interfere with the characteristics of the color filter.

In particular, when manufacturing the substrate with a color filter of the present invention, a step of baking at a high temperature is substantially unnecessary, so that a plastic material can be used. When a plastic material is used, it is preferable that the surface is hard-coated before use. When using ordinary soda lime glass, it is preferable to previously form a film such as SiO ₂ as an alkali barrier by a method such as CVD.

The light-shielding layer (black matrix) 2 is provided to ensure the color separation of the colors of the color filter, and may not be provided depending on the required degree of color separation. Normally, it is provided below the colored layer 3,
It may be provided on the colored layer. As the material, a single layer of an inorganic substance such as metallic chromium or chromium oxide, or a multilayered combination thereof, a dye-receiving layer such as gelatin dyed with a dye, or an organic resin mixed with a pigment is used. it can.

These materials are printed on a substrate in a predetermined pattern or formed on the entire surface of the substrate by a method such as electrolytic plating, chemical plating, vapor deposition, and sputtering, and then patterned by photolithography to form a predetermined shape. Form a film. As the pattern, a striped pattern or a matrix pattern may be appropriately adopted according to the application.

The coloring layer 3 comprises a coloring agent holding layer (porous film) and a coloring agent held in the coloring agent holding layer. here,
The colorant holding layer is a mixture of inorganic particles such as silica and alumina, particularly inorganic oxide particles having excellent transparency, and a binder resin. From the viewpoint of increasing the ink holding power, it is preferably a mixture of coagulated boehmite particles, that is, an alumina hydrate having a pseudo-boehmite structure, and a binder resin. The colorant retaining layer has sufficient pores to absorb the ink. As a result, the same smoothness as before coloring can be maintained after coloring.

The coagulated boehmite particles need to be easily dispersed as a sol in a dispersion medium in order to improve the coatability on a substrate, and it is desirable that the particle size distribution be such. On the other hand, as the binder resin, it is preferable to use a water-soluble binder resin or a monomer or an oligomer, instead of a water-insoluble binder resin that requires a large amount of various stirrers such as a dispersant and a homogenizer. That is, it is preferable to use water as the dispersion medium and to use it as an aqueous coating liquid.

As a raw material of the pseudo-boehmite particles, those having a small amount of cationic impurities such as sodium are preferable from the viewpoint of enhancing the reliability of the liquid crystal. For example, aluminum alkoxide is suitable. In this case, as the alkoxide used in the reaction, aluminum triisopropoxide, aluminum trisec butoxide and the like can be used, but it is particularly preferable to use aluminum isopropoxide. This is because IPA has suitable reactivity and is easy to handle, and because the by-product during hydrolysis is IPA, which is an azeotropic mixture with water, it is easy to remove.

Any binder resin can be used as long as it is soluble in the dispersion medium. For example, when water is used as the dispersion medium, water-soluble resins such as melamine resin, vinyl acetate, polyvinyl alcohol, polyvinylpyrrolidone, polyvinyl acetal, hydroxycellulose resin, starch and its modified products, SBR latex, NBR latex are used. can do. Particularly preferred binder resin is polyvinyl alcohol partially acetalized. According to this, together with the sealing material of the present invention, it is possible to more completely prevent the strength of the porous film from being lowered.

Colorant (ink) retained in the colorant retaining layer
As the dye, a dye having a good absorbability is suitable. Particularly preferred are water-soluble dyes, and more preferred are acid dyes that electrostatically associate with cationically charged pseudoboehmite.
As the dye structure, known structures such as azo type, phthalocyanine type and anthraquinone type can be appropriately used, and in some cases, a complex having a metal ion at the center may be used. A sulfonic acid group, an amino group, a carboxyl group or the like can be used as the functional group imparting anionicity. The presence of cation ions such as sodium in the dye may elute the cation ions into the liquid crystal layer. Therefore, these ions are preferably removed by a method such as salting out or ion exchange.

As a method for absorbing the ink in the colorant-holding layer, it is very preferable to use a non-impact printer, especially an inkjet printer. Other than this, known dyeing methods and various printing methods such as screen printing and offset printing can also be adopted. When using the inkjet printing method, in particular, three or more ink nozzles are arranged in parallel,
The method of forming three colors at the same time is most preferable in terms of mass productivity.

As the method for forming the porous layer, coating and drying may be carried out in the same manner as a method for coating a usual coating material. For example, coagulated boehmite sol and binder resin are mixed by an appropriate method to prepare a coating solution using water as a solvent, and blade coating method, air knife coating method, bar coating method, spin coating method, spraying method, roll coating method, etc. A known method for forming the thin film can be adopted. A water-soluble organic solvent such as an alcohol solvent such as methanol, a nonpolar solvent such as acetone, or a polar solvent such as N-methylpyrrolidone can be appropriately added to the coating liquid. If necessary, a water-soluble plasticizer such as glycerin, a surfactant, a dispersant, a stabilizer, a gelling agent, etc. can be added.

An oil-soluble material is used as the sealing material for forming the sealing layer 4 in the present invention. It is particularly preferable to use a hydrophobic one. Specifically, it is preferable that the main component is polyepoxide or silicone. As the precursor of polyepoxide, a monoepoxy represented by bisphenol A type, bisphenol F type, phenol novolac type, cresol novolac type, alicyclic epoxy, and various functional groups / halogenated products thereof, Also, various functional monomers / oligomers having an epoxy group as a functional group can be used alone or as a mixture of several kinds.

A coating liquid is prepared by dissolving these substances or precursors for forming these substances in a solvent, and the coating liquid is coated on the dye-retaining layer by an appropriate method, and a curing reaction is carried out if necessary. As the solvent that can be used in this case, there is a solvent composition mainly composed of a lipophilic solvent. Specifically, aromatic solvents such as benzene, toluene and xylene, 1,1,1
-Halogen-based solvents such as trichloroethane and trichloroethylene, CFC-based solvents such as R-225 and R-1416,
Alcoholic solvents such as methanol and ethanol, aliphatic solvents such as cyclohexane, hexane and decane, so-called reactive diluents having functional groups such as epoxy / acryl, etc. can be used alone or in any mixing ratio. It is not limited to this as long as the strength of the porous membrane is not substantially reduced.

If necessary, a light stabilizer, a defoaming agent, an antioxidant, a leveling agent, a surfactant, a catalyst and the like can be introduced. Since the coating liquid needs to penetrate into the porous film without destroying it, the viscosity of the coating liquid is
It is preferably 200 cP or less.

The coating thickness is preferably less than 2.0 μm including the protective layer described above above the dye holding layer. If it is thicker than this, cracks and waviness are likely to occur, which may adversely affect the refractive index and the like.

When the transparent film according to the present invention is insufficient in terms of smoothness, hardness, etc., in order to further protect the color filter and provide a stable screen, the transparent electrode and the liquid crystal layer at the uppermost part of the color filter are provided. A protective layer may be provided on the border with the.

In this case, since there is no direct contact with the porous film, various organic resins and inorganic substances can be used. However, a relatively high hardness is required in order to prevent compression from the outside in the subsequent process such as liquid crystal injection and to keep the color filter flat.

As a method of forming the protective layer, a sputtering method or a CVD method can be used in addition to the same method as that of the porous film.

In addition, a characteristic common to the colorant, the porous film, the sealing layer and the protective layer is that the physical properties do not change in the subsequent steps, particularly during the ITO film formation, that is, under a vacuum of 200.
It is preferable that it has heat resistance such that it does not substantially discolor at a high temperature of about ° C. Further, in order to enhance the reliability of the liquid crystal, it is preferable that the amount of ionic impurities such as sodium is small.

Next, an electrode layer is formed on the protective layer. The electrode layer is made of aluminum, chromium or the like.
Further, the transmissive display needs to be light transmissive, and it is generally preferable to use indium tin oxide (ITO) or tin oxide, but the present invention is not limited to this. Further, the electrode layer may be patterned corresponding to the display, or may be a solid electrode when used as a common electrode. The method for forming the electrode layer is not particularly limited to this, but from the viewpoint of making the layer thickness uniform, a vapor deposition method, a sputtering method, or the like is preferably used.

[0039] In the present invention, SiO ₂ above or below the substrate electrode if necessary, TiO ₂ or the like of the insulating film, TFT, MIM, active elements such as thin film diode, a phase difference film, polarizing film, A reflective film, a photoconductive film or the like may be formed.

Further, in the case of a liquid crystal display, an alignment film is formed on the electrode-attached substrate, if necessary. This may be obtained by rubbing an organic resin film of polyimide, polyamide, polyvinyl alcohol, or the like, may be obliquely vapor-deposited of SiO, or may be used by applying a vertical alignment agent.

Further, as a method of manufacturing a liquid crystal display element, a method which is usually used can be adopted. That is,
One of the pair of substrates is the electrode substrate with the color filter, the other is a substrate with an electrode that is appropriately patterned, and a liquid crystal alignment film is formed on the substrate as necessary,
Next, the electrode surfaces of the pair of substrates are opposed to each other, the peripheral portions are sealed, and the liquid crystal is sealed inside. This makes it possible to obtain a color liquid crystal display having high definition.

From the viewpoint of application, the substrate with a color filter of the present invention includes a liquid crystal display surface, a cathode ray tube display surface, a light receiving surface of an image pickup tube, and the like. Further, since a color filter having extremely small thickness unevenness can be obtained, it is particularly preferable for a liquid crystal element in which the accuracy of the substrate spacing is strict.

[0043]

【Example】

[Example 1] Chromium was formed on the entire surface of a glass substrate by sputtering, a pattern on a black mask was formed by photolithography, and etching was performed.

Next, a pseudo-boehmite sol was synthesized.
204.25 g of aluminum triisopropoxide,
751 g of isopropanol and 900 g of water are mixed,
Hydrolysis was performed for 24 hours in a 2000 cc glass reactor to obtain a white sol liquid.

50 parts by weight of this pseudo-boehmite sol was mixed with "ESREC K" (trade name: Sekisui Chemical Co., Ltd.) as a water-soluble binder, and the mixture was applied by spin coating to the above-mentioned substrate having a black mask formed thereon, and at 150 ° C. It was heated for 30 minutes and fixed to form an ink receiving layer.

Next, an RGB stripe pattern was formed by using the ink jet method. Next, main agent: "Epicoat 1001" (trade name: Epoxy Shell epoxy) 65 parts by weight, curing agent: BF ₃ monomethylamine 35 parts by weight, solvent: mixture of toluene and 1-methoxy-2-propanol 30 parts by weight A coating solution having a composition of was prepared and applied to the above substrate by spin coating, heated at 150 ° C. for 1 hour, and cured to form a sealing layer.

Further, "X-12-2206" (trade name: manufactured by Shin-Etsu Silicone) was applied to the above substrate by spin coating and cured at 150 ° C. to form a protective layer.

The printed image was maintained clear, the defect of insufficient strength did not occur, and the color characteristics as a liquid crystal color filter were maintained.

[Comparative Example] The same procedure as in Example 1 was performed except that the sealing layer and the protective layer were formed as follows.

Tripropylene glycol diacrylate (manufactured by Daicel), which is freely soluble in water as a main agent 47.
Application of a composition comprising 5 parts by weight, 2.5 parts by weight of 2-methyl-1- (4- (methylphenyl) -2-morpholinopropane) as a curing agent, and a mixture of water and 25 parts by weight of acetone as a solvent. A liquid was prepared and applied on the above-mentioned substrate by spin coating, and was irradiated with ultraviolet rays to be cured to form a sealing layer.

Further, "RN-812" (trade name: polyimide coating agent manufactured by Nissan Chemical Industries, Ltd.) was applied onto the above-mentioned substrate by spin coating, irradiated with ultraviolet rays and cured to form a protective layer.

In this case, the strength of the porous film was insufficient, line color mixing and fading occurred, and the color characteristics of the liquid crystal color filter could not be satisfied.

[Example 2] When a substrate with a color filter prepared by this method was incorporated as a substrate in a liquid crystal module, a clear color image was obtained.

[0054]

By forming a color filter by the method according to the present invention, simultaneous formation of three colors is possible,
A low-cost, highly reliable color filter that can be manufactured using a relatively small-scale apparatus can be obtained.

According to the present invention, the pore-sealing material can easily penetrate into the porous membrane, and complete pore sealing is possible without lowering the strength of the porous membrane, and haze can be prevented.

Further, in the color filter of the present invention, when the transparent coating material is an organic resin containing polyepoxide or silicone as a main component, a color filter having a high adhesiveness with the ink receiving layer and a high durability is obtained. To be

Further, if a separate flattening film is provided on the color filter, higher smoothness can be obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a substrate with a color filter of the present invention.

[Explanation of symbols]

 1: Substrate 2: Light-shielding layer 3: Colored layer 4: Sealing layer 5: Protective layer 6: Electrode layer

Claims (5)

[Claims] 1. A colored layer formed on a substrate by pattern-coloring a porous layer comprising inorganic particles and a water-soluble binder resin with a coloring agent, and a transparent sealing material layer for sealing the porous layer. A substrate with a color filter, wherein the transparent sealing material or its precursor is oil-soluble. 2. The sealing material is an organic resin containing polyepoxide or silicone as a main component.
Substrate with the described color filter. 3. The substrate with a color filter according to claim 1, wherein the colorant is a water-soluble dye. 4. The substrate with a color filter according to claim 1, wherein the inorganic particles are pseudo-boehmite sols. 5. A liquid crystal display device using the substrate with a color filter according to any one of claims 1 to 4 as at least one substrate.