JPH04324803A - Manufacture of color filter - Google Patents

Abstract

PURPOSE:To prevent display irregularity by putting and pressing a flexible mold having a surface with a few recesses and projections on a layer on which a compound for protective film made of an ultraviolet ray hardening resin is applied and hardening it with ultraviolet rays. CONSTITUTION:A layer on which a violet ray hardening resin 24 for protective film is applied is provided on a transparent substrate 21 on which a black matrix 22 and a coloring layer 23 are formed. A photosensitive resin in which photopolymerizing acrylate-oligomer blended with multi-functional photopolymerizing acrylatemonomer is used as the composition of the protective film. Then, the smooth surface of a mold 25 is faced to the application layer and a violet ray 26 is radiated thereon in the state of pressing the surface uniformly. After hardening of the protective film, the mold is separated from above the protective film. In this case, because the mold has flexibility, the mold can be separated easily from a filter without bring damage to the color filter, a protective film with few recess and projection can be provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter used in color liquid crystal display devices, and more particularly to a method for manufacturing a color filter in which the unevenness of a protective film formed on a colored layer is extremely reduced.

0002

[Prior Art] A liquid crystal display device consists of a transparent substrate, such as glass, provided with transparent electrodes, with a gap of approximately several micrometers, and a liquid crystal substance sealed in between.The liquid crystal is oriented in a certain direction by a voltage applied between the electrodes. An image is displayed using transparent and opaque areas formed by aligning the image. A color liquid crystal display device has three color filters of red (R), green (G), and blue (B) corresponding to the three primary colors of light on one of the transparent electrode substrates. The desired color is displayed by adding primary colors.

A color filter for a color liquid crystal display device has a transparent substrate, a colored layer, a protective film, and a transparent conductive film laminated in this order, and a transparent substrate on which electrodes or thin film transistors are formed facing each other at the positions of the three primary colors of RGB. A few μ
A liquid crystal display device is formed by keeping a distance of m and filling a liquid crystal material.

0004

[Problems to be Solved by the Invention] Color filters are produced by separating adjacent colored layers and providing a black matrix 32 that acts as a light shield on a transparent substrate such as glass 31, as shown in the cross-sectional view of FIG. , pigment dispersion method, dyeing method,
A colored layer 33 with the three primary colors R, G, and B in a predetermined shape is formed by an electrodeposition method, a printing method, etc., a protective film 34 is formed on the colored layer for the purpose of protecting the colored layer, and a protective film is further formed. A transparent electrode 35 for driving the liquid crystal is formed on the transparent electrode 35 .

[0005] Color liquid crystal display devices come in two types, the simple matrix type and the active matrix type, depending on the method of driving the liquid crystal.Recently, color liquid crystal display devices are used for display devices such as personal computers, which have excellent image quality and are capable of reliably controlling each pixel. The active matrix method is being adopted because it is possible to do this and has a fast operation speed.

In an active matrix type liquid crystal display device, a thin film transistor (TFT) element is formed on a glass substrate for each pixel, and the shutter action of the liquid crystal of each pixel is controlled by the switching action of each element. A uniform transparent electrode is formed on the opposite electrode of these elements.

[0007] When there is a difference in the thickness of each of the colors R, G, and B of the colored layer, the change in the thickness of the colored layer also appears as unevenness on the protective film formed on the colored layer. In a liquid crystal display device using TFT, the thickness of the liquid crystal sealed part is about 5 μm, so even the slightest unevenness formed on the protective film affects the difference in the optical rotation of the liquid crystal, causing unevenness on the display surface. The unevenness on the film needs to be as small as about 0.3 μm to 0.5 μm. In order to reduce the unevenness of the protective film, it is necessary to make the thickness of the colored layer constant, but in order to prevent unevenness from forming on the protective film even when the thickness of the colored layer differs. In addition, it has been proposed to form a protective film having a smooth surface by irradiating ultraviolet rays and curing an ultraviolet curable resin or the like coated on a colored layer while pressing it with a flat mold. However, in such a method, since the mold and the protective film to be formed are pressurized by the press, when the mold and the protective film are to be released after curing, they come into close contact with each other, making it difficult to release from the mold. If a strong force is used to separate the color filter, the thin glass substrate used as the color filter substrate may be damaged during release.

[0008]

[Means for Solving the Problems] The present inventors have studied means for solving the above-mentioned problems, and have developed a mold for pressing the ultraviolet curing resin coated on the colored layer, which has flexibility and smoothness. We have discovered a method of forming a smooth surface on the protective film using a laminated material that transmits ultraviolet rays with excellent properties.

[0009] Flexible UV-transparent materials include various synthetic resin films or thin plates, but since these are manufactured by methods such as stretching or casting, they have many pinholes and irregularities. have. Therefore, if the protective film is cured by ultraviolet rays while being pressed by these methods, sufficient smoothness required for the protective film of a color filter cannot be obtained. Therefore, we created a smooth protective film by laminating a flexible thin plate and a smooth resin layer, applying pressure to the UV-curable resin coating film with the smooth resin surface, and curing the resin by irradiating it with UV rays. It forms the

[0010] The resin used as the smooth surface for smoothing the protective film has high hardness and may crack or break when bent.
Many transparent resins that do not peel off from the flexible material can be used, including many thermosetting resins and ultraviolet curable resins, but it is particularly preferable to use ultraviolet curable resins. .

As the ultraviolet curable resin, polyester acrylate, epoxy acrylate, polyurethane acrylate, polyether acrylate, alkyd acrylate, melamine acrylate, etc. can be used.

[0012] Furthermore, a mold release agent can be mixed into the ultraviolet curable resin so that the ultraviolet curable resin can be more easily released from the smooth surface of the glass after curing. As the mold release agent, silicone oil, fluorine-based surfactant, silicone-modified acrylate, fluorine-modified acrylate, etc. can be used.

Various materials can be used as the flexible material as long as it is transparent and transmits ultraviolet rays, but acrylic resin, polyethylene terephthalate, etc. having a thickness of 0.5 mm to 1.0 mm are preferable. Further, the surface of the flexible material can be treated with a primer using a vinyl acetate resin, an epoxy resin, an isocyanate resin, an acrylate resin, a titanium coupler, or the like to improve its adhesion to the ultraviolet curable resin.

The laminate thus obtained has an extremely smooth surface and flexibility.

[0015] In the press mold prepared as described above, after applying an ultraviolet curable resin for a protective film on the colored layer of the color filter, the smooth side of the mold with the cured ultraviolet curable resin is directed toward the coated surface. The mold is released from the color filter after being cured by irradiating ultraviolet rays in the pressed state, but since the mold is flexible, it can be easily released from the ultraviolet curable resin.

Various resins can be used as the protective film in the color filter of the present invention, but if a photosensitive resin is used, it is easy to form a protective film at a desired location on the color filter, so that UV rays can be removed. Preferably, a curable resin is used. As the ultraviolet curing resin, one consisting of a photopolymerizable acrylate oligomer and a polyfunctional photopolymerizable acrylate monomer can be used. The photopolymerizable acrylate oligomer has a molecular weight of 1000~
About 2000 is preferable, and examples include polyester acrylate, epoxy acrylate such as phenol novolac epoxy acrylate, o-cresol novolac epoxy acrylate, polyurethane acrylate, polyether acrylate, alkyd acrylate, melamine acrylate, etc. Examples of the polymerizable acrylate monomer include 1,4-butanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, pentaerythritol acrylate, dipentaerythritol hexaacrylate, and the like.

Furthermore, compared to the photopolymerizable resin in which a multifunctional photopolymerizable acrylate monomer is added to the photopolymerizable acrylate oligomer as described above, the mixture of the photopolymerizable acrylate oligomer and the epoxy resin contains By using a photosensitive acrylic resin to which a polyfunctional photopolymerizable acrylate monomer having multiple functional groups is added, the degree of cross-linking of the resin can be increased and a film with high rigidity and hardness can be formed. It is preferable to treat the surface to improve adhesion with the ultraviolet curable resin. The photopolymerizable acrylate oligomer that can be used for this purpose preferably has a molecular weight of about 1000 to 2000, and includes polyester acrylate, epoxy acrylate such as phenol novolac epoxy acrylate, o-cresol novolac epoxy acrylate, polyurethane acrylate, Examples include polyether acrylate, alkyd acrylate, and melamine acrylate.

Examples of the epoxy resin include phenol novolac type epoxy resins and cresol novolac type epoxy resins having the structural formulas of Compound 1 and Compound 2 below.

[0019]

[Chemical formula 1]

[0020] Examples of the polyfunctional photopolymerizable acrylate monomer include 1,4 butanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate,
Examples include pentaerythritol acrylate and dipentaerythritol hexaacrylate.

The protective film was formed by adding a photopolymerizable acrylate oligomer, a phenol novolac type epoxy resin, a multifunctional photopolymerizable acrylate monomer, a polymerization initiator, and an epoxy curing agent onto the colored layer provided on the transparent substrate. After applying the photosensitive resin by any coating method such as a spinner method, a roll method, a spray method, or a screen printing method, the above-mentioned smooth mold is placed and the protective film is cured by ultraviolet rays under pressure. At this time, a mask with a desired pattern drawn on it is placed and UV rays are irradiated to cure only the necessary areas, and the uncured photosensitive resin in the areas that were not irradiated with UV rays is dissolved and removed using a solvent. By this method, a protective film can be formed only in a predetermined area.

[0022]

[Operation] The color filter manufacturing method of the present invention uses a laminate made of a flexible material and a resin having an extremely smooth surface as a mold, and uses the smooth surface of the mold as a protective film coated on a colored layer. A smooth protective film is formed by irradiating ultraviolet rays while being in close contact with the resin composition and under pressure.The mold is flexible, so when the mold is peeled off, it does not touch the substrate. It can be easily released from the mold without causing damage.

[0023]

[Example] A method for manufacturing a laminate having a smooth surface used in the method of the present invention will be explained with reference to FIG.
As shown in (A), an ultraviolet curing resin 2 was applied onto a transparent smooth plate 1 made of glass or the like, and then a flexible transparent plate 3, which would become the base material of the mold, was pressed as shown in (B) of the same figure. In this state, ultraviolet rays 4 are irradiated to cure the ultraviolet curable resin layer. After curing, the mold is flexible and can be easily released. It is preferable to coat the surface of the flexible transparent plate in contact with the ultraviolet curable resin with a salt-vinyl acetate resin or the like to increase the adhesion with the ultraviolet curable resin, and the surface of the smooth plate in contact with the ultraviolet curable resin It is preferable to apply an ultraviolet curable silicone resin or the like to improve mold releasability. As the smooth plate 1, a glass plate having an extremely smooth surface, such as soda lime glass or borosilicate glass, whose surface is polished to a mirror finish can be used. Many photocurable resins that can be integrated with the flexible transparent plate can be used as long as they have high hardness, including polyester acrylate, epoxy acrylate, polyurethane acrylate, and polyether acrylate. , alkyd acrylate, melamine acrylate, etc. Further, it is preferable to apply a mold release agent on the smooth plate, and as the mold release agent, an ultraviolet curing silicone resin such as Evecryl (manufactured by Shin-Etsu Chemical Co., Ltd.) can be used.

A method for manufacturing a color filter using the mold obtained as described above will be explained with reference to FIG.
As shown in FIG. 2A, a coating layer of an ultraviolet curing resin 24 for a protective film is provided on a transparent substrate 21 on which a black matrix 22 and a colored layer 23 are formed.

[0025] Many compositions can be used for the protective film, and a photosensitive resin in which a polyfunctional photopolymerizable acrylate monomer is added to a photopolymerizable acrylate oligomer has excellent properties after curing. Therefore, it is preferable.

Examples of the photopolymerizable acrylate oligomer include polyester acrylate, epoxy acrylate such as phenol novolak epoxy acrylate, o-cresol novolac epoxy acrylate, polyurethane acrylate, polyether acrylate, oligomer acrylate, alkyd acrylate,
Polyol acrylate, melamine acrylate, etc. can be mentioned, and examples of the polyfunctional photopolymerizable acrylate monomer include 1,4 butanediol diacrylate, diethylene glycol diacrylate, neopentyl glycol diacrylate, pentaerythritol triacrylate, and trimethylol. Examples include propane triacrylate, pentaerythritol acrylate, dipentaerythritol hexaacrylate, and the like.

Furthermore, in the photopolymerizable resin, as an initiator, benzophenone, Irgacure 184, Irgacure 907, Irgacure 651 (all brand names of Ciba Geigy), Darocure (trade name of Merck & Co., Ltd.), etc. are added at a solid content ratio of 1 to 3. % may be added.

A particularly suitable blending ratio (wt%) of the photopolymerizable acrylate oligomer and the polyfunctional photopolymerizable monomer is shown in Blend Example 1: Phenol novolak epoxy acrylate...
60% trimethylolpropane triacrylate
…17% dipentaerythritol hexaacrylate …20% Irgacure 184
... 3% blending example 2 O-cresol novolak epoxy acrylate...60
% dipentaerythritol hexaacrylate
…38% Irgacure 184
...2% blending example 3 Polyurethane acrylate
…50% dipentaerythritol hexaacrylate …48% Irgacure 651
…
2% blending example 4 Melamine acrylate
…70% trimethylolpropane triacrylate …27% Irgacure 1
84
... You can raise 2%, etc.

Furthermore, the blending ratio (% by weight) of a composition containing an epoxy resin in a photopolymerizable acrylate oligomer and a polyfunctional photopolymerizable monomer is as follows: Blend Example 5 Phenol novolak epoxy acrylate...
40% phenol novolac type epoxy resin
…18% trimethylolpropane triacrylate …17% dipentaerythritol hexaacrylate …20% Irgacure 18
4
...3% UVE1014 (manufactured by GE)
... 2% blending example 6 O-cresol novolak epoxy acrylate...38
%Cresol novolac type epoxy resin
…18% dipentaerythritol hexaacrylate …38% Irgacure 184
…2%U
VE1014 (manufactured by GE)
...2% blending example 7 Polyurethane acrylate
…35% phenol novolac type epoxy resin …13% dipentaerythritol hexaacrylate …48% UVE10
14 (manufactured by GE)
…2% Irgacure 651
...2% blending example 8 Melamine acrylate
…49% phenol novolac type epoxy resin …20% trimethylolpropane triacrylate …27% UV
E1014 (manufactured by GE)
…2% Irgacure 184
... You can raise 2%, etc. Subsequently, as shown in FIG. 2B, ultraviolet rays 26 are irradiated with the coating layer being uniformly pressed so that the smooth surface of the mold 25 faces the coating layer. After the protective film has hardened, the mold is separated from the protective film. Since the mold is flexible, it is easy to remove the mold from the color filter without damaging the color filter, as shown in Figure 2 (C). It can be separated and a protective film with less unevenness can be obtained.

Example 1 A mixture of 100 parts of epoxy acrylate and 1 part of silicon-modified acrylate as an ultraviolet curable resin was applied to a thickness of 0.1 mm on a smooth plate made by polishing a 3 mm thick glass substrate to a mirror finish. did. On the other hand, one side of a flexible plate made of 0.5 mm thick acrylic plate was coated with salt-vinyl acetate resin.
．． The coated surface was applied at a coating weight of 1 g/mm2, the coated surface was brought into close contact with the surface of the coating layer of the above-mentioned ultraviolet curable resin, and while pressure was applied from above, ultraviolet rays were irradiated for 10 seconds using a 2.0 kW ultra-high pressure mercury lamp. After the curable resin had hardened, the flexible plate integrated with the applied ultraviolet curable resin was separated from the smooth plate to obtain a mold with a smooth surface. The unevenness of the smooth surface of the obtained mold was in the range of 0.01 μm to 0.03 μm.

Red, green, and blue colored photosensitive resins are prepared by dispersing red, green, and blue pigments in a photosensitive resin at the composition ratios (% by weight) shown below.

(1) Red photosensitive resin pyrazolone red (red pigment)
…10 polyvinyl alcohol/5% stilbazolium quinolium …5
(Photosensitive resin) Water

...85(2) Green photosensitive resin Lionol Green 2Y-301 (green pigment)
…9 Polyvinyl alcohol/5%
Stilbazolium quinolium...5 (photosensitive resin) water

...86(3) Blue photosensitive resin Fast Dogen Blue (blue pigment)
… 3 polyvinyl alcohol/5% stilbazolium quinolium …
5 (Photosensitive resin) Water

...For the 92 substrate, a 1.1 mm thick glass substrate (AL material manufactured by Asahi Glass Co., Ltd.) was used after being thoroughly cleaned. A black matrix with a size of 20 μm×40 μm was formed.

A red photosensitive resin was applied thereon to a thickness of 1.2 μm, then dried in an oven at a temperature of 70°C for 30 minutes, exposed using a mercury lamp, and exposed to water. Spray development is performed for 1 minute to form a red relief image in the area where red pixels are to be formed, and further developed at 150°C.
It was heated and cured for 30 minutes.

The same process was repeated to form a green relief pixel in the area where the green pixel was to be formed, and a blue relief pixel in the area where the blue pixel was to be formed, thereby forming a colored layer.

Next, as a photocurable acrylate oligomer, 50 parts by weight of o-cresol novolac epoxy acrylate (molecular weight 1,500 to 2,000), and as a polyfunctional polymerizable monomer, dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku Co., Ltd.) was added. ) and 2 parts by weight of Irgacure (manufactured by Ciba Geigy) as a polymerization initiator was dissolved in 200 parts by weight of ethyl cellosolve acetate. 10 g of the solution was applied onto the colored layer using a spin coater to a thickness of 2.0 μm.

Next, the smooth side of the mold obtained in Example 1 was placed facing the coated layer of the protective film compound, and while applying pressure uniformly, unnecessary parts of the protective film were shielded from light. A photomask was placed, and ultraviolet rays were irradiated for 10 seconds using a 2.0 kW ultra-high pressure mercury lamp. Next, 1,1 at a temperature of 25℃
, 2,2-tetrachloroethane for 1 minute to remove only the uncured portions of the coating film.

[0037] The unevenness of the surface of the obtained protective film is 0.01 μm.
It was within the range of 0.05 to 0.05 μm.

[0038]

Effects of the Invention: A flexible mold with a surface with very little unevenness is placed on a coating layer of a composition for a protective film made of an ultraviolet curable resin, and the coating is cured with ultraviolet light under pressure.
When removing the mold from above the protective film, it can be easily removed without damaging the color filter, and after forming a film on the protective film, it is attached to a substrate having TFTs etc. to manufacture a color liquid crystal display device. Since the layer thickness is uniform, an excellent liquid crystal display device with no display unevenness can be obtained.

[Brief explanation of the drawing]

[Figure 1] Diagram showing the manufacturing process of a smooth mold

FIG. 2 is a diagram showing the method for manufacturing a color filter of the present invention.

[Figure 3] Partial cross-sectional view of color filter

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Smooth plate, 2... Ultraviolet curable resin, 3... Flexible transparent plate, 4... Ultraviolet rays, 21... Transparent substrate, 22... Black matrix, 23... Colored layer, 24... Ultraviolet curable resin, 31...
Glass, 32...black matrix, 33...colored layer,
34...Protective film, 35...Transparent electrode

Claims (1)

[Claims] Claim 1: A transparent flexible material is laminated on an uncured synthetic resin composition coated on a smooth board, and the uncured synthetic resin composition is cured under pressure. The smooth surface of the flexible material laminate of the synthetic resin composition obtained by releasing from the mold is placed in contact with the uncured ultraviolet curable resin composition applied on the colored layer of the color filter. A method for manufacturing a color filter, characterized by forming a protective film by irradiating ultraviolet rays under pressure.