JPH05333201A - Production of color substrate - Google Patents

Abstract

(57) [Summary] [Purpose] Even when a printing method is adopted, a thin-film color filter having good flatness and high precision is manufactured, and the thin-film color filter is industrially advantageous in color. It is an object to provide a method for obtaining a substrate. [Constitution] On the base material sheet (1a) made of a shrinkable sheet,
Enlarged color pixel with size larger than target size
After providing (2a), the base sheet (1a) is contracted to obtain a color filter in which fine color pixels (2b) having a target size are formed on the contracted base sheet (1b). Then, the fine color pixels (2
A thermosetting or active energy ray-curing resin liquid is supplied between b) and the smoothing template material (3) so that the resin liquid is supported in a layered manner between the two, and then the supporting layer is formed. The step of curing to form a cured layer (c) and the step of providing the substrate layer (6) on the base sheet (1a) side of the formed color filter by a casting method are carried out in any order.

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 used for the purpose of a color liquid crystal display or the like.

[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) colored layer, an overcoat layer and a transparent layer on a glass substrate. It has a structure provided with electrodes.

The black matrix layer plays a role as a light-shielding layer for preventing a decrease in contrast due to LCD light leakage 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, and B includes mosaic type, triangle type, stripe type, and 4-pixel arrangement type.

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

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

[0007]

In order to mix the three primary colors with the naked eye, it is necessary to miniaturize the filter so that the repeating pitch of the same color is 300 μm or less. Since the pattern accuracy and flatness of the color directly affect the color of the screen, the dimensional accuracy of the pattern must be suppressed to the order of several μm or less, and the flatness is preferably ±
0.1μm or ± 0.2μm or less (especially for STN ± 0.
05 μm or less) is required.

Color LCDs are currently very expensive because color filters are very expensive.

Among the methods for forming the colored layer, the printing method is originally a mass-reproduction technique in a short process, the apparatus / running cost is low, and it is possible to process a large area.
Although it is expected to be a method capable of mass production and cost reduction, there is a problem that it is essentially inferior to other methods in terms of flatness and pattern accuracy.

That is, in the printing method, since the viscous ink is pressure-bonded to the ink, it is difficult to obtain the accuracy of the pattern end portion, and the deviation or the unevenness is likely to occur. The accuracy of the printing method is a mass production level and the pattern resolution is 70 to 100μ.
m, dimensional accuracy of ± 15 μm per 300 mm, flatness of ±
It is about 0.5 μm.

Under these circumstances, the printing method has a considerably low yield at present and is not so low in cost as compared with other methods such as the photolithography method. If it is possible to form a colored layer having good flatness and high accuracy even by a printing method, its usefulness becomes immeasurable.

Against this background, the present invention manufactures a thin film color filter having good flatness and high accuracy even when the printing method is adopted.
It is an object of the present invention to provide a method for industrially advantageously obtaining a color substrate from the thin film color filter.

[0013]

The method for manufacturing a color substrate of the present invention comprises: a base sheet (1a) made of a shrinkable sheet; and an enlarged color pixel (2) having a size larger than a target size.
After providing a), by shrinking the substrate sheet (1a), to obtain a color filter in which fine color pixels (2b) having a target size are formed on the shrinked substrate sheet (1b) In the manufacturing process A, a thermosetting or active energy ray-curable resin liquid is supplied between the fine color pixels (2b) of the formed color filter and the smoothing template material (3) so that the resin liquid can be applied between them. Of the color filter and the flattening step B in which the carrier layer is cured to form a cured layer (c), and the formed base sheet of the color filter (1).
a substrate layer installation step C in which the substrate layer (6) is provided on the a) side by a casting method, and after the step A is performed, the step B and the step C
Are carried out simultaneously or in any order.

The present invention will be described in detail below. In the present invention, the “sheet” means a thin film and does not limit the thickness.

Color filter manufacturing process A As the base sheet (1a) made of a shrinkable sheet, heating,
A transparent sheet having a property of uniaxially or biaxially contracting by means of moisture, irradiation of active energy rays, release of a mechanically stretched state, or the like is used. The substrate sheet (1a) preferably has a retardation value of 60 nm or less when contracted.

Particularly, a heat-shrinkable sheet obtained by stretching a thermoplastic sheet in a uniaxial or biaxial direction and omitting the heat setting, or heat setting it under the condition that the shrinkability is not lost is important. Is. Here, the thermoplastics include polyethylene, crosslinked polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polycarbonate, polysulfone, polyester, polyamide, hydrochloric acid rubber, polyvinyl alcohol, ethylene-. Examples include vinyl alcohol copolymers, polyvinylpyrrolidone, and cellulose derivatives.

The R, G, B enlarged color pixels (2a) are preferably formed on the substrate sheet (1a) by a printing method. Printing of the enlarged color pixel (2a) is set to a size larger than the target size, so that the printing method can be adopted. Examples of the printing method include offset printing, planographic offset printing, intaglio offset printing, screen printing, flexographic printing, and gravure printing. As the ink, there may be used an ink containing a dye and a solvent, an ink containing a binder further added thereto, a pigment (preferably pulverized to 0.1 μm or less), an ink containing a solvent and a binder. The black matrix layer (4) is usually formed before or after the enlarged color pixel (2a) is formed.

The pattern arrangement of the R, G, B enlarged color pixels (2a) can be a mosaic type, a triangle type, a stripe type, a four-pixel arrangement type, or the like.

After the color filter material is obtained as described above, the base material sheet (1a) is contracted according to the contraction behavior of the base material sheet (1a). For example, when the base material sheet (1a) has heat shrinkability, it is heated to shrink.

As a result, a color filter in which fine color pixels (2b) having a target size are formed on the contracted base sheet (1b) can be easily obtained.

In the flattening process B and the present invention, the formed fine color pixel (2
A thermosetting or active energy ray-curable resin liquid is supplied between b) and the smoothing template material (3) so that the resin liquid is supported in layers between the two, and then the supporting layer is formed. It is cured to form a cured layer (c).

Examples of the thermosetting resin liquid include phenoxy ether type crosslinkable resin, epoxy resin, acrylic resin, acrylic epoxy resin, melamine resin, phenol resin and urethane resin. Particularly preferred resins are as follows. It is a phenoxy ether type polymer represented by Chemical formula 1.

[0023]

[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. )

As the active energy ray-curable resin liquid, a prepolymer or / and a monomer having photopolymerizability, and optionally other monofunctional or polyfunctional monomer, various polymers, a photopolymerization initiator, and a sensitizer are added. The compounded resin composition is used.

Examples of the photopolymerizable prepolymer include polyester acrylate, polyester urethane acrylate, epoxy acrylate and polyol acrylate, and examples of the photopolymerizable monomer include monofunctional acrylate, bifunctional acrylate and 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, in addition to the above, phosphazene resins are also preferably used.

When the active energy ray curable resin is an ultraviolet curable resin, a small amount of a photoinitiator or a sensitizer is usually used together, 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 specific methods for obtaining the cured layer (c) having good flatness is to use a thermosetting type or an active type in the gap between the fine color pixels (2b) and the smoothing template material (3) made of a smooth film. An energy ray-curable resin solution is supplied so that the resin solution is sandwiched between the two, and then the sandwiching layer is cured by heating or irradiation with active energy rays (ultraviolet rays or electron beams). This is the method of forming with layer (c). The heating conditions and irradiation conditions (integrated light intensity and dose) are set in the optimum range in consideration of the thickness of the hardened layer (c), etc., and the smooth release property of the smoothing mold material (3) and the hardened layer (c) Try to ensure solvent resistance.
The smoothing template material (3) is peeled off at an arbitrary stage after the removal.

As the smoothing template material (3) 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 the smoothing template material (3) 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, those not containing a filler, the surface smoothness is remarkably improved by the biaxial stretching, so that the flatness can be maximized.

The second method for obtaining a cured layer (c) having good flatness is to cast a resin solution on the fine color pixels (2b) or one of the smoothing template materials (3) made of a smooth film. While the casting layer is covered with the smoothing template material (3) or the fine color pixel (2b) side of the color filter, the sandwich layer is cured by controlling the sandwich layer thickness by the roll gap.
This is the method (c).

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

Hardened layer (c) formed by each of the above methods
The surface roughness of the free surface is less than 0.3 μm, preferably 0.2 μm, depending on the degree of surface smoothness of the smoothing template material (3).
Hereafter, it is more preferably 0.1 μm or less. In general,
The surface roughness of the melt-extruded film is 2-3 μm or more for 100 μm thick film, and the surface roughness of the cast film is 0.5-1 μm for 100 μm thick film. Has a very low surface roughness. Further, the cured layer (c) also has excellent heat resistance, solvent resistance, and transparent electrode forming property.

The thickness of the cured layer (c) 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.

Substrate Layer Setting Step C In the present invention, the substrate layer (6) is provided on the base sheet (1a) side of the color filter obtained in the above step A by a casting method.

As the substrate layer (6), a general base material layer (polycarbonate, polymethylmethacrylate, polyethersulfone, polysulfone, polyarylate, amorphous polyolefin, polyamide, etc.), a gas proof resin layer (ethylene-vinyl alcohol copolymer) is used. And a crosslinked resin cured product layer (phenoxyether type crosslinkable resin, etc.). Layers obtained by appropriately combining these layers (air-permeable resin layer / base material layer, air-permeable resin layer). / Substrate layer / Air-permeable resin layer / Crosslinkable resin cured product layer, Crosslinkable resin cured product layer / Air-permeable resin layer / Substrate layer / Air-permeable resin layer /
Crosslinked resin cured product layer).

Since the substrate layer (6) is required to have optical isotropy,
It is necessary to use the casting method.

Color Substrate After performing the above step A, the color substrate of the present invention can be obtained by performing step B and step C simultaneously or in any order.

When used in a color liquid crystal display, the cured layer is formed after the step B is completed or after the color substrate is manufactured.
A transparent electrode (5) such as ITO is formed on (c).

The total thickness of the color substrate including the substrate layer (6) is preferably about 50 to 1000 μm.

A liquid crystal display is produced by enclosing a liquid crystal between the color substrate and the counter substrate to form a liquid crystal cell, and laminating a polarizing plate and, if necessary, a retardation plate on the liquid crystal cell. .. The counter substrate may be a glass substrate or a plastic substrate.

[0044]

As described above, the enlarged color pixel (2a) having a size larger than the target size (for example, 2 times or more, preferably 3 times or more in area) is formed on the base sheet (1a) made of a shrinkable sheet. After providing, the color filter is obtained by shrinking the base sheet (1b) on which fine color pixels (2b) having a target size are formed. For example, a base sheet (1a) made of a shrinkable sheet that shrinks to 1 / n in one axial direction is used, the enlarged color pixel (2a) is set to n times the target value, and printing is performed. It may be contracted and returned to 1 / n. The fine color pixel (2b) after contraction not only has a smaller size, but also has a higher color density according to the contraction rate.

In the color filter thus obtained, since the hardened layer (c) having excellent flatness is formed on the fine color pixel (2b), the performance as a color filter is extremely high. It is excellent.

A base sheet for this color filter
Since the substrate layer (6) by the casting method is provided on the (1a) side, the color filter itself also serves as one substrate of the liquid crystal cell.

[0047]

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 substrate of the present invention.

An ethylene-vinyl alcohol copolymer film having a thickness of 30 μm was stretched under heating by 4 times in each of the longitudinal and transverse directions, and then heat-set so as not to impair the shrinkability to obtain a heat-shrinkable film (1a). ..

After the black matrix layer (4) was printed on the heat-shrinkable film (1a), magnified color pixels (2a) of R, G, and B were sequentially printed using a dye-based ink. The size of each enlarged color pixel (2a) is 280
It was set to μm square.

The color filter material thus obtained was kept in a heated atmosphere and heat-shrinked in the lengthwise and crosswise directions to 1/4 each to obtain the size before stretching.

As a result, fine color pixels (2b) having a target size (each 70 μm square) were formed on the contracted base sheet (1b). The color density of the fine color pixel (2b) was higher than that of the enlarged color pixel (2a).

Separately, as a smoothing template material (3), 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., Ltd.
10000 cp / 25 ° C.) 3 parts, and further 2 parts of benzophenone were added and mixed to prepare a resin solution of the active energy ray-curable resin composition.

[0055]

[Chemical 2]

After casting this resin solution on the surface of the smoothing template material (3), the fine color pixel (2b) side of the color filter is overlaid on the casting surface, and the UV irradiation device is used. Ultraviolet irradiation was performed under the following conditions.

Ultraviolet Irradiation Conditions Ultraviolet Irradiation Device Ushio Electric Co., Ltd. UVC-253
/ 1MNLC3-AA08 lamp High pressure mercury lamp 120W / cm Irradiation distance 200mm Conveyor speed 3m / min

The sandwiching layer was cured by irradiation with ultraviolet rays to become an active energy ray-curable resin cured layer (c). As a result, a laminate having a layered structure of the smoothed template material (3) / active energy ray curable resin cured layer (c) / fine color pixel (2b) / base material sheet (1b) was obtained. Then smoothing mold material (3)
Was removed by peeling, but the peeling removability was smooth.

The thickness of the cured layer (c) of the color filter having the cured layer (c) thus obtained was 5 μm, the pencil hardness of the surface was 4H, and the surface smoothness of the free surface was based on light interference. 0.05 μm (that is ± ±
0.025 μm) or less, the solvent resistance of the surface (dimethylacetamide, 44 ± 1 ° C., 5 minutes) was good, and the adhesion between the cured layer (c) and the fine color pixel (2b) was also good.

Next, 40 parts of a phenoxyether resin (manufactured by Toto Kasei Co., Ltd.) and 4 parts of methyl ethyl ketone were placed on the base sheet (1b) side of the color filter having the above-mentioned cured layer (c).
0 part, 20 parts of cellosolve acetate, 7 of an adduct of tolylene diisocyanate and trimethylolpropane
A thermosetting resin solution having a composition of 40 parts of a 5% solution (“Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) was cast, dried at 80 ° C. for 4 minutes, and further heated at 110 ° C. for 40 minutes. A 70 μm-thick substrate layer (6) consisting of a phenoxyether resin-based crosslinkable resin cured layer was formed.
As a result, the intended color substrate was obtained.

A transparent electrode (5) made of an ITO layer having a thickness of 700 Å was directly formed on the surface of the cured layer (c) of this color substrate by a sputtering method.

Liquid crystal is sealed between this color substrate and a counter substrate (glass substrate or plastics substrate) with ITO to form a liquid crystal cell, and polarizing plates are laminated from both sides of the liquid crystal cell to form a color LCD. Assembled The performance of this color LCD is far superior to that of a color LCD using a color filter by a conventional printing method.

Example 2 In the same manner as in Example 1, a color filter was manufactured in which fine color pixels (2b) having a target size were formed on the contracted base sheet (1b).

Phenoxyether resin (manufactured by Tohto Kasei Co., Ltd.) 40 parts, methyl ethyl ketone 40 parts, cellosolve acetate 20 parts, 75% solution of an adduct of tolylene diisocyanate and trimethylolpropane (“Coronate L” manufactured by Nippon Polyurethane Co., Ltd.) ) A thermosetting resin solution having a composition of 40 parts was prepared, and the resin solution was used as the smoothing template material as in Example 1 and the fine color pixel (2b).
While discharging the resin liquid in a gap between (3) and the resin liquid so as to be sandwiched between them, the resin liquid is dried at 80 ° C. for 4 minutes and further heated at 120 ° C. for 20 minutes to obtain a phenoxy ether resin system. The cured crosslinkable resin layer (c) was formed, and then the smoothing template material (3) was peeled off.

The cured layer (c) of the color filter thus obtained had a thickness of 3 μm and a surface pencil hardness of 3H.
The surface smoothness of the free surface is 0.05 μm (that is ± 0.025 μm) μ as measured by a non-contact surface roughness meter that uses light interference.
m or less, surface solvent resistance (dimethylacetamide, 44
± 1 ℃, 5 minutes) is good, cured layer (c) and fine color pixels
The adhesion with (2b) was also good.

Then, in the same manner as in Example 1, a substrate layer (6) having a thickness of 80 μm and composed of a phenoxyether resin-based crosslinkable resin cured layer was formed to obtain a color substrate.

On the surface of the cured layer (c) of this color substrate, a transparent electrode (5) made of an ITO layer having a thickness of 700 angstrom was directly formed by a sputtering method.

Liquid crystal is enclosed between this color substrate and a counter substrate (glass substrate or plastic substrate) with ITO to form a liquid crystal cell, and polarizing plates are laminated from both sides of the liquid crystal cell to form a color LCD. Assembled The performance of this color LCD is far superior to that of a color LCD using a color filter by a conventional printing method.

[0069]

According to the present invention, since the enlarged color pixel (2a) having a size larger than the target size is provided on the base material sheet (1a) made of a shrinkable sheet, it is possible to achieve a precision of a normal level. The technique can accurately form the pattern without failure.

Then, since this is contracted, the fine color pixel (2b) having the target size is obtained.
A color filter in which is formed is obtained.

In addition, even if the film thickness of the enlarged color pixel (2a) formed on the base material sheet (1a) is made thin (thus the color density is not so dark), the color density becomes dark due to contraction. There are also advantages.

Furthermore, in the color filter obtained by the present invention, the surface of the fine color pixel (2b) is a cured layer.
It is flattened to the limit by (c).

Therefore, the drawbacks of the printing method, which has been difficult in the prior art in terms of accuracy, flatness, and yield, and which is not necessarily advantageous over other methods, are completely eliminated. Therefore, the advantage of the printing method that the device / running cost is low in a short process and the processing of a large area can be utilized as it is, and the mass production of the color filter and the cost reduction can be achieved.

A base sheet for this color filter
Since the substrate layer (6) by the casting method is provided on the (1a) side, the color filter itself also serves as one substrate of the liquid crystal cell, which is a completely different structure from the conventional color substrate. ..

[Brief description of drawings]

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

[Explanation of symbols]

 (1a) ... Substrate sheet, heat-shrinkable film, (1b) ... Shrinked substrate sheet, (2a) ... Enlarged color pixel, (2b) ... Fine color pixel, (R) ... Red pixel, (G ) Green pixel, (B) Blue pixel, (4) Black matrix layer, (5) ITO, transparent electrode, (6) Substrate layer, (c) Hardened layer

Claims (1)

[Claims] 1. A magnifying color pixel (2a) having a size larger than a target size is provided on a base material sheet (1a) made of a shrinkable sheet, and then the base material sheet (1a) is shrunk, Color filter manufacturing process A for obtaining a color filter in which fine color pixels (2b) having a target size are formed on a contracted base sheet (1b), smoothing with fine color pixels (2b) of the formed color filter A thermosetting or active energy ray-curable resin liquid is supplied between the mold material (3) and the resin liquid so that the resin liquid is supported in layers between the two, and then the supporting layer is cured to form a cured layer. (c) a flattening treatment step B, and a substrate layer setting step C in which a substrate layer (6) is provided on the substrate sheet (1a) side of the formed color filter by a casting method. After performing step B and step C simultaneously or in any order A method for producing a color filter, which is characterized by being carried out.