JPH05313012A - Color filter manufacturing method - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a method for industrially producing a color filter having extremely excellent flatness. [Structure] A colored layer (2) consisting of red, green, and blue color pixels on a substrate (1) such as a glass substrate, and a smoothing template material (4) having a smooth surface such as a smooth biaxially stretched polyethylene terephthalate film (4). 2) is supplied with a resin liquid (a) of a composition of a thermosetting or active energy ray-curable resin so that the resin liquid (a) is sandwiched between them. Then, the sandwiching layer (b) is cured to form a cured layer (3). The surface roughness of the hardened layer (3) is 0.3 μm (ie ± 0.15 μm) or less.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a color filter used for a purpose such as a color liquid crystal display, especially a color filter having an extremely excellent surface flatness.

[0002]

2. Description of the Related Art A color filter used in a liquid crystal display (LCD) includes a black matrix layer, a red (R), a green (G) and a blue (B) coloring layer and an overcoat layer (protection layer) on a glass substrate. Layer), and further a transparent electrode.

The black matrix layer plays a role of a light-shielding layer for preventing a decrease in contrast due to light leakage to the LCD and for suppressing a light leakage current of the TFT element.

The colored layer determines the most important optical properties of the color filter. The pattern arrangement of R, G, B includes a mosaic type, a triangle type, a stripe type, a 4-pixel arrangement type and the like.

The overcoat layer is a layer for protecting the coloring layer, protecting it from contamination, and imparting flatness. The flatness is imparted by polishing the surface after forming the overcoat layer.

As the method for forming the colored layer, there are a printing method applying the principle of printing, a dyeing method using photolithography, a pigment dispersion method, and an electrodeposition method in which a dye is electrochemically attached.

[0007]

The color LCD has a TF.
There are T method and STN method, and the requirement for flatness is rather strict in the STN method. The required flatness is, for example, about ± 0.2 μm at the practical level (about 0.5 μm because flattening is difficult in the case of the printing method), but the color LCD manufacturer wants ± 0.05 μm or less. There is.

[0008] By providing an overcoat layer on the colored layer, flattening is performed to some extent, but since the flatness is insufficient, as described above, the surface is usually polished after the overcoat layer is formed. Therefore, the flatness is improved.

However, since the work of polishing the overcoat layer which is a resin layer is extremely difficult, the yield is remarkably reduced and the cost is increased. Further, even if such polishing is performed, the flatness is increased beyond a certain limit. There was a problem of not having.

When the flatness of the over-auto layer is inferior, the flatness of the transparent electrode such as ITO formed thereon is also inferior, and the gap between the two substrates enclosing the liquid crystal is only 5 mm.
In the case of a color LCD of only about 6 μm, the color display quality of the screen becomes very poor.

If the smoothness of the surface of the overcoat layer can be increased to the utmost without polishing, and as a result, the gap between the two substrates facing each other can be maintained accurately and uniformly, the color of the screen will be improved. The display quality is remarkably improved and the cost can be reduced.

Under the circumstances, the present invention has an object to provide a method for industrially producing a color filter having excellent flatness.

[0013]

The method for producing a color filter according to the present invention comprises a thermosetting type or a gap in the gap between the colored layer (2) on the substrate (1) and the smoothing template material (4) having a smooth surface. A resin liquid (a) of an active energy ray-curable resin composition is supplied so that the resin liquid (a) is sandwiched between the two layers, and then the sandwiching layer (b) is cured to form a cured layer. (3) is a feature.

The present invention will be described in detail below.

As the substrate (1), in addition to a usual glass substrate for liquid crystal cells, a plastic substrate, an image sensor surface, a display surface and the like are used. In the case of a plastic substrate, a base material layer (polycarbonate, polymethylmethacrylate, polyethersulfone, polysulfone, polyarylate, amorphous polyolefin, polyparabanic acid resin, polyamide, etc.), a gas permeable resin layer (ethylene-vinyl alcohol copolymer) Combined layer, polyvinyl alcohol layer, etc.) or crosslinked resin cured product layer (phenoxyether type crosslinkable resin, etc.), or a layer in which these layers are appropriately combined and laminated (air-permeable resin layer / base material layer, air-permeable property) Resin layer / base material layer / air permeable resin layer / crosslinkable resin cured material layer, crosslinkable resin cured material layer / air permeable resin layer / base material layer / air permeable resin layer / crosslinkable resin cured material layer, etc. ) Is preferred.

The formation of the colored layer (2) on the substrate (1), that is, the formation of R, G, and B pixels is performed by a printing method, a dyeing method using photolithography, a pigment dispersion method, or an electrochemical dye. It is made by an electrodeposition method or the like.

The pattern arrangement of R, G, and B pixels can be a mosaic type, a triangle type, a stripe type, a four-pixel arrangement type, or the like.

The film thickness and resolution in the case of the printing method, the dyeing method and the pigment dispersion method are as follows, for example, but they are being further improved.

In the present invention, the colored layer on the substrate (1)
A resin solution (a) of a thermosetting or active energy ray-curable resin composition is supplied into the gap between the (2) and a smoothing template material (4) having a smooth surface, and the resin solution (a) is a mixture of the two. The layers are sandwiched between them, and then the sandwiching layer (b) is cured to form a cured layer (3).

Examples of the thermosetting resin liquid (a) include phenoxy ether type crosslinkable resin, epoxy resin, acrylic resin, acrylic epoxy resin, melamine resin, phenol resin and urethane resin, and particularly preferable ones. Is a phenoxy ether type polymer represented by the following chemical formula 1.

[0021]

[Chemical 1]

(Wherein R ^{1 to} R ⁶ are each hydrogen, a lower alkyl group having 1 to 3 carbon atoms or Br, R ⁷ is a lower alkylene group having 2 to 4 carbon atoms, m is an integer of 0 to 3, n is 2
It means an integer of 0 to 300, respectively. )

The active energy ray-curable resin liquid (a) includes a photopolymerizable prepolymer or / and a monomer, and optionally other monofunctional or polyfunctional monomer, various polymers, a photopolymerization initiator, and an additive. A resin composition containing a sensitizer is used.

Examples of the photopolymerizable prepolymer include polyester acrylate, polyester urethane acrylate, epoxy acrylate, and polyol acrylate. The photopolymerizable monomer is a monofunctional acrylate, a bifunctional acrylate, or a trifunctional or higher functional acrylate. Are exemplified. Of these, epoxy acrylates, which have good physical properties after curing, are particularly useful, so it is desirable to use at least part of them.

As the photopolymerizable prepolymer or monomer, a phosphazene resin is preferably used in addition to the above.

When the active energy ray curable resin is an ultraviolet curable resin, a small amount of a photoinitiator or a sensitizer is usually used in combination, but depending on the kind of the resin, it is cured even if it is irradiated with ultraviolet rays without blending them. There are cases. As the photoinitiator, various photocuring agents such as acetophenones, benzophenones, Michler's ketone, benzyl, benzoin, benzoin ether, benzyl ketals and thioxanthones are used, and as sensitizers, amines and diethylaminoethyl methacrylate are used. Various sensitizers are used.

In addition to the active energy ray-curable resin, a polyisocyanate compound may be blended for modification, or a small amount of a solvent or the like may be blended. Here, as the polyisocyanate compound, tolylene diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or a modified product thereof, isophorone diisocyanate, tolidine diisocyanate, lysine diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, tetramethyl xylene diisocyanate, p-phenylene diisocyanate, etc. Examples include various polyisocyanates and adducts or prepolymers of these polyisocyanates,
In particular, derivatives of relatively long-chain aliphatic polyisocyanates such as hexamethylene diisocyanate are preferred. The compounding amount of the polyisocyanate compound is 2 to 30 with respect to the active energy ray-curable resin liquid.
It is desirable to occupy about wt%.

One of the concrete methods for obtaining the cured layer (3) having good flatness is a gap between the surface of the colored layer (2) on the substrate (1) and the smoothing template material (4) made of a smooth film. The resin solution (a) of the thermosetting or active energy ray-curable resin composition is supplied to the resin solution (a) so that the resin solution (a) is sandwiched between the two and then heated or activated energy ray (UV or The sandwich layer (b) is cured by irradiation with an electron beam) to form a cured layer.
This is the method (3). The heating conditions and irradiation conditions (integrated light intensity and dose) are set within the optimum range in consideration of the thickness of the hardened layer (3), etc., and smooth peeling of the smoothing mold material (4) and the resistance of the hardened layer (3) are set. Be sure to keep the solvent. The smoothing template material (4) is peeled and removed at an arbitrary stage after that.

As the smoothing mold material (4) in the above,
Biaxially oriented polyester film such as biaxially oriented polyethylene terephthalate sheet, biaxially oriented polybutylene terephthalate sheet, biaxially oriented polyethylene naphthalate sheet, or biaxially oriented polypropylene film is used. Stretched polyethylene terephthalate film is of particular importance. In this case, if the surface is subjected to corona discharge or flame treatment, it will be difficult to peel off the smoothing template material (4) in the subsequent steps, so be careful to use one that is not subjected to such treatment. ..

The surface roughness of these smooth films is
0.15 μm or less, preferably 0.1 μm or less, further 0.05
It is required to be less than μm, and if the surface roughness exceeds 0.15 μm, desired flatness cannot be obtained. Among the above-mentioned biaxially stretched polyethylene terephthalate films, which do not contain a filler, the surface smoothness is remarkably improved by the biaxial stretching, so that the smoothness can be maximized.

The second method for obtaining the cured layer (3) having good flatness is to apply the resin solution (a) to one of the colored layer (2) on the substrate (1) or the smoothing template material (4) made of a smooth film. ) Is cast and the smoothing template material (4) or the coloring layer (2) side of the substrate (1) with the coloring layer (2) is covered with the sandwiching layer (b ) Is controlled, and the sandwiching layer (b) is cured to form a cured layer (3).

A third method for obtaining a cured layer (3) having good flatness is to cast a resin solution (a) on a colored layer (2) on a substrate (1) and to form a cast layer on the cast layer. This is a method of curing the sandwiching layer (b) to form a cured layer (3) while controlling the thickness of the sandwiching layer (b) while pressing a smoothed glass as a smoothing template material (4). In this method, the glass used is used repeatedly.

Hardened layer (3) formed by each of the above methods
The surface roughness of the free surface is 0.3 μm (that is, ± 0.15 μm) or less, preferably 0.2 μm or less, more preferably 0.1 μm, depending on the degree of surface smoothness of the smoothing template material (4).
It is less than m. Generally, the surface roughness of melt-extruded film is 2-3 μm or more for 100 μm thick film,
Since the surface roughness of the cast film is 0.5 to 1 μm for a 100 μm thick film, the surface roughness of the free surface of the hardened layer (3) is extremely small. Further, the cured layer (3) also has excellent heat resistance, solvent resistance, and transparent electrode forming property.

The thickness of the hardened layer (3) can be set appropriately,
If it is too thick, hue shift or narrowing of the viewing angle may occur, so the thickness is often set to 1 to 20 μm, particularly 2 to 10 μm.

A transparent electrode (5) is usually further formed on the cured layer (3). For the formation of the transparent electrode (5), a vacuum deposition method, a sputtering method, an ion plating method, a metal spraying method, a metal plating method, a chemical vapor deposition method, a spray method or the like is adopted, and the sputtering method is particularly important. The material of the transparent electrode is mainly Sn, In, Ti, Pb.
, Tb and the like or oxides thereof are used, and the layer thickness of the electrode is usually at least 100 angstroms, more preferably 200 angstroms or more.

The color filter thus obtained is useful as a color filter for color separation in various applications such as a liquid crystal display and a color image sensor.

[0037]

In the color filter produced by the method of the present invention, the cured layer is formed on the surface of the colored layer (2) on the substrate (1).
Since (3) is provided and the surface of the cured layer (3) is extremely flat, the LCD manufactured using this color filter has a significantly improved color display quality on the screen.

[0038]

EXAMPLES The present invention will be further described with reference to examples. Hereinafter, “parts” means parts by weight.

Example 1 FIG. 1 is an explanatory view showing an example of a manufacturing process of a color filter of the present invention.

A black matrix layer (BM) is formed on a glass plate as an example of the substrate (1) according to a usual printing method, and then R, G and B color pixels are sequentially printed,
A colored layer (2) was formed.

Separately, as a smoothing template material (4), a thickness of 50
A biaxially stretched polyethylene terephthalate film (O type manufactured by Teijin Ltd.) having a surface roughness of 0.01 μm or less and not subjected to corona discharge treatment was prepared.

100 parts of epoxy acrylic resin "V-2550P" manufactured by Nippon Steel Chemical Co., Ltd., "Coronate 2094" manufactured by Nippon Polyurethane Industry Co.
10000 cp / 25 ° C.) 4 parts, and further 2 parts of benzophenone were added and mixed to prepare a resin liquid (a) of the active energy ray-curable resin composition.

[0043]

[Chemical 2]

This resin liquid (a) is treated with the above smoothing template material (4)
After casting on the surface, the colored layer (2) side of the substrate (1) with the above colored layer (2) was superposed on the casting surface, and ultraviolet irradiation was performed under the following conditions with an ultraviolet irradiation device. ..

UV irradiation conditions UV irradiation device UVC-253 manufactured by Ushio Electric Co., Ltd.
/ 1MNLC3-AA08 lamp High pressure mercury lamp 120W / cm Irradiation distance 200mm Conveyor speed 3m / min

The sandwiching layer (b) is cured by irradiation with ultraviolet rays,
It became the active energy ray-curable resin cured layer (3). As a result, a laminate having a layer structure of smoothed template material (4) / active energy ray-curable resin cured layer (3) / colored layer (2) / substrate (1) was obtained. Then, the smoothing template material (4) was peeled and removed, and the peeling and removability was smooth.

The cured layer (3) of the color filter thus obtained has a thickness of 5 μm and a surface pencil hardness of 4H.
The surface smoothness of the free surface is 0.05 μm (that is, ± 0.025 μm) or less as measured by a non-contact type surface roughness meter using light interference, and the surface solvent resistance (dimethylacetamide, 44 ± 1)
C., 5 minutes) was good, and the adhesion between the cured layer (3) and the colored layer (2) was also good.

Next, a transparent electrode (5) made of an ITO layer having a thickness of 800 Å was directly formed on the surface of the cured layer (3) of the color filter obtained above by a sputtering method.

A liquid crystal was sealed between a substrate made of this color filter and a counter substrate with electrodes to form a liquid crystal cell, and polarizing plates were laminated on both sides of the liquid crystal cell to assemble a color LCD. The performance of this color LCD is
Color L using a conventional printing color filter
It was far superior to the CD.

Example 2 As a substrate (1), there was prepared a glass plate on which a colored layer (2) consisting of R, G and B color pixels was formed by a dyeing method utilizing photolithography.

Example 1 was repeated except that the above substrate was used as the substrate (1) with the colored layer (2), and the smoothing template material (4) was used.
/ Active energy ray curable resin cured layer (3) / Colored layer (2)
/ A laminate having a layer structure of the substrate (1) was obtained. Then, the smoothing template material (4) was peeled and removed, and the peeling and removability was smooth.

The cured layer (3) of the color filter thus obtained had a thickness of 4 μm and a surface pencil hardness of 4H.
The surface smoothness of the free surface is 0.05 μm (that is, ± 0.025 μm) or less as measured by a non-contact type surface roughness meter using light interference, and the surface solvent resistance (dimethylacetamide, 44 ± 1)
C., 5 minutes) was good, and the adhesion between the cured layer (3) and the colored layer (2) was also good.

Example 3 A phenoxy ether (manufactured by Tohto Kasei Co., Ltd.) 40 was used in place of the resin liquid (a) of the active energy ray-curable resin composition.
Part, 40 parts of methyl ethyl ketone, 20 parts of cellosolve acetate, 40 parts of a 75% solution of an adduct of tolylene diisocyanate and trimethylolpropane (“Coronate L” manufactured by Nippon Polyurethane Industry Co., Ltd.) 40 parts Example 1 was repeated except that (a) was used for drying at 80 ° C. for 4 minutes and further heated at 130 ° C. for 20 minutes to form a phenoxyether-based crosslinkable resin cured layer (3).

The cured layer (3) of the color filter thus obtained had a thickness of 4 μm and a surface pencil hardness of 3H.
The surface smoothness of the free surface is 0.05 μm (that is, ± 0.025 μm) or less as measured by a non-contact type surface roughness meter using light interference, and the surface solvent resistance (dimethylacetamide, 44 ± 1)
C., 5 minutes) was good, and the adhesion between the cured layer (3) and the colored layer (2) was also good.

[0055]

EFFECTS OF THE INVENTION In the color filter substrate of the present invention, since the cured layer (3) provided on the colored layer (2) on the substrate (1) is extremely flat, The color display quality of the screen of the color LCD manufactured by using is significantly improved.

Despite such excellent performance, it has an industrial advantage that its manufacturing process is simple.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a manufacturing process of a color filter of the present invention.

[Explanation of symbols]

(1) ... substrate, (2) ... colored layer, (R) ... red pixel, (G) ... green pixel, (B) ... blue pixel, (B
M) ... Black matrix layer, (3) ... Hardened layer, (4) ... Smoothing template material, (5) ... Transparent electrode

Claims (2)

[Claims] 1. A resin liquid (a) containing a thermosetting or active energy ray-curable resin composition in a gap between a colored layer (2) on a substrate (1) and a smoothing template material (4) having a smooth surface. ) Is supplied so that the resin liquid (a) is sandwiched between the two, and then the sandwiching layer (b) is cured to form a cured layer (3). Method. 2. The method for producing a color filter according to claim 1, wherein the cured layer (3) has a surface roughness of 0.3 μm (that is, ± 0.15 μm) or less.