JPH06300914A - Base material for transfer and production of color filter formed by using the same - Google Patents

Abstract

PURPOSE:To provide a technique for production of the color filters capable of industrially easily and surely form fine colored layers free from unequal colors with good accuracy even if a printing method is adopted. CONSTITUTION:The first base material for transfer provided with magnified color pixels 2a which have the size larger than a target size and are formed of transferable ink on a sheet 1a for transfer consisting of shrinkable sheat is obtd. These pixels are then shrunk, by which the second base material for transfer formed with the fine color pixels 2 having the target size on a sheet 1 for transfer after shrinkage is obtd. The fine color pixels 2 formed on this second base material for transfer are transferred onto the base material 3 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter used for the purpose of a color liquid crystal display or the like. It also relates to a transfer base material for producing such a color filter.

[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 arrangements of R, G, B include 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 surface smoothness (flatness). Transparency, heat resistance, light resistance, and chemical resistance are also required.

As a method of 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 of electrochemically attaching a dye, 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, for example, 300 μm or less. Since the pattern accuracy and surface smoothness 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 surface smoothness is also smoothness of ± 0.1 μm or ± 0.2 μm. Is required.

Among the methods for forming the colored layer, the printing method can be mass-produced and cost-reduced in that it is originally a mass-reproduction technique, has low equipment / running cost, and can process a large area. Although it is expected to be a method, there is a problem that it is essentially inferior to other methods in terms of pattern accuracy, surface smoothness, color unevenness and the like.

That is, in the printing method, since the viscous ink is pressure-bonded to the ink, it is difficult to obtain the precision of the end portion of the pattern, which easily causes misalignment or unevenness, and uneven color. The accuracy of the printing method is such that the pattern resolution is 70 to 100 μm, the dimensional accuracy is ± 15 μm per 300 mm, and the surface smoothness is ± 0.5 μm at the mass production level.

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 with high accuracy and no color unevenness by the printing method, its usefulness will be immeasurable.

Under the circumstances described above, the present invention is a color capable of industrially and easily and reliably forming a fine colored layer with high accuracy and without color unevenness even when a printing method is adopted. It is intended to provide a filter manufacturing technology.

[0012]

The first transfer base material of the present invention comprises a transfer sheet (1a) made of a shrinkable sheet, and a transferable ink having a size larger than a target size. The enlarged color pixel (2a) is provided.

The second transfer base material of the present invention is a contraction product of the above-mentioned first transfer base material, and is a fine color pixel having a target size on the transfer sheet (1) after contraction. (2) is formed.

According to the method of manufacturing a color filter of the present invention, an enlarged color pixel (2a) having a size larger than a target size and made of a transferable ink is provided on a transfer sheet (1a) made of a shrinkable sheet. By contracting the first transfer base material, a second transfer base material having fine color pixels (2) having a target size formed on the contracted transfer sheet (1) is obtained. It is characterized in that the fine color pixels (2) formed on the transfer base material (2) are transferred to the base material (3) side.

The present invention will be described in detail below. In addition, in this invention, a "sheet" means a thin layer thing and does not limit thickness.

The transfer sheet (1a) made of a shrinkable sheet is uniaxial by means such as heating, moisture absorption / water absorption, active energy ray irradiation, release of mechanically stretched state, and utilization of shape memory property due to the property of the polymer itself. Alternatively, a sheet having a property of shrinking in biaxial directions (particularly biaxial directions) is used. The transfer sheet (1a) may be transparent or opaque, and its thickness is not limited. The particularly preferable transfer sheet (1a) is a heat-shrinkable sheet obtained by uniaxially or biaxially stretching a thermoplastic sheet and then heat-setting it under a condition that the shrinkage is not lost. Stretching or stretching (stretching with virtually no orientation)
After that, a thermoplastic sheet in which the stretched or stretched state is mechanically fixed can also be used as the transfer sheet (1a).

The R, G, B magnified color pixels (2a) can be formed on the transfer 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. Printing methods include letterpress printing, offset printing, gravure printing, screen printing, flexographic printing, and the like.

In the present invention, the magnified color pixel (2a) is formed of transferable ink. As the transferable ink, those used as transfer printing inks such as sublimation transfer printing ink, pigment transfer printing ink, and wet transfer printing ink are used, and sublimation transfer printing ink is particularly important.

Here, as the sublimation transfer printing ink, for example, an ink composed of a disperse dye and a vehicle is used. Examples of disperse dyes include nitro dyes, azo dyes, quinophthalone dyes, anthraquinone dyes, and the like.As vehicles, ethyl cellulose, hydroxyethyl cellulose, cellulose acetate butyrate, polyvinyl alcohol, sodium alginate, modified starch,
Alkyd resin, acrylic resin, modified phenolic resin, petroleum resin, resin such as polymerized linseed oil or fat and oil components,
Examples of the solvent include water, alcohols, hydrocarbons, esters, ethylene glycol monoalkyl ethers, and solvent components such as mineral terpenes.

The pattern arrangement of the R, G, and B enlarged color pixels (2a) can be a mosaic type, a triangle type, a stripe type, a four-pixel arrangement type, or the like. The enlarged black matrix layer (4a) is formed simultaneously with the formation of the enlarged color pixel (2a), or before or after the formation.

On the transfer sheet (1a) made of a shrinkable sheet as described above, the enlarged color pixel (2a) (and the enlarged black matrix layer (4a )) Is provided to form the first transfer base material, and then the transfer sheet (1a) is contracted according to the contraction behavior of the transfer sheet (1a). For example, transfer sheet (1
If a) has heat shrinkability, heat it to shrink it. As a result, the second transfer base material is obtained in which the fine color pixels (2) (and the fine black matrix layer (4)) having the target size are formed on the transfer sheet (1) after contraction. .

Next, fine color pixels are formed as described above.
The second transfer base material on which (2) is formed is used, and this second transfer base material is transferred to the base material (3) side. When the transferable ink is sublimation transfer printing ink, the second
The transfer base material may be heat-treated and transferred in a state of being overlaid on the base material (3).

The substrate (3) used herein has a retardation value of 60 nm or less (particularly 40 nm or less) and a visible light transmittance of 70% or more, for example, polyethylene, crosslinked polyethylene, polypropylene, ethylene-vinyl acetate. Copolymer, amorphous polyolefin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polycarbonate, polysulfone, polyether sulfone, polyarylate, polyester, polyamide, hydrochloric acid rubber, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, cellulose derivative, gelatin A single-layer or multi-layer film of polyurethane, phenoxy ether-based polymer, epoxy resin or the like, or glass is used. When the transferable ink is sublimation transfer printing ink,
Since (3) is required to have the ability to accept sublimable dyes, if a material lacking such ability is used as the substrate (3), gelatin, chitin,
It is desirable to form a layer having a good ability to accept sublimable dyes such as chitosan, silicon-modified polyvinyl alcohol and polyester by means such as coating or laminating.

If necessary, an overcoat layer (5) is provided on the fine color pixels (2) transferred and formed on the substrate (3), and a transparent electrode (6) such as ITO is further provided thereon. Let it form. In some cases, the transparent electrode (6) is first formed on the substrate (3) and then the fine color pixel (2) is formed.

When the base material (3) in the above is a thin layer plastic sheet, the color filter obtained is in the form of a film, so depending on the application, a substrate (an ordinary glass substrate for a liquid crystal display cell, other than , Plastics substrate, image sensor surface, display surface, etc.) and the like. In the case of a plastic substrate, a base material layer, a gas permeable layer or a crosslinkable resin cured product layer,
Alternatively, a layer in which these layers are appropriately combined and laminated is suitable. The above-mentioned overcoat layer (5) and transparent electrode
(6) is installed by installing the above color filter on a glass substrate,
It can also be performed after laminating on a plastic substrate or the like.

The color filter of the present invention is useful as a color filter for color separation in various applications such as a liquid crystal display and a color image sensor.

[0027]

Function: An enlarged color pixel (2a) having a size larger than a target size (for example, twice or more, preferably three times or more in area) and having a transferable ink on the transfer sheet (1a) made of a shrinkable sheet. When the first transfer base material provided with) is contracted, a second color pixel (2) having a target size is formed on the contracted transfer sheet (1).
To obtain a transfer base material.

For example, a transfer sheet (1a) made of a shrinkable sheet, which shrinks to 1 / n in one axis direction, is used, and the enlarged color pixel (2a) is set to n times the target value for printing. Then, when this is contracted and returned to 1 / n, not only the size of the contracted fine color pixel (2) becomes smaller but also the color density becomes darker according to the contraction rate and the color unevenness becomes smaller.

If the second transfer base material having such fine color pixels (2) formed thereon is transferred to the base material (3) side,
The desired color filter can be easily obtained.

[0030]

EXAMPLES The present invention will be further described with reference to examples. FIG. 1 is an explanatory view showing an example of a manufacturing process of a color filter of the present invention.

Example 1 An ethylene-vinyl alcohol copolymer film was stretched in the lengthwise and crosswise directions by 4 times under heating and then heat-set so as not to impair the shrinkability, and a heat-shrinkable transfer sheet (1a). Got

After printing the magnified black matrix layer (4a) on the transfer sheet (1a) using an ink containing a sublimable dye, R, G and B are also printed using the ink containing a sublimable dye. The magnified color pixels (2a) were sequentially printed. The size of each enlarged color pixel (2a) was set to 280 μm square. It is also possible to print the enlarged color pixel (2a) and then print the enlarged black matrix layer (4a).

The thus-obtained first transfer base material was kept in a heating atmosphere and heat-shrinked in each of the lengthwise and crosswise directions by 1/4 to obtain the size before stretching.

As a result, fine color pixels (2) (and fine black matrix layer (4)) having a target size (each 70 μm square) on the transfer sheet (1) after shrinkage.
As a result, a second transfer base material in which the film was formed was obtained. The color density of the fine color pixel (2) was higher than that of the enlarged color pixel (2a), and the color unevenness was extremely small.

Next, the second transfer base material on which the fine color pixels (2) were formed was applied to a polyurethane resin sheet (composition of phenoxyether resin and polyisocyanate) having a thickness of 30 μm and a retardation value of 5 nm. Fine color formed on the second transfer base material by heat treatment for about 2 minutes at a temperature of about 110 ° C. in a state that the base material (3) made of a material is adhered and laminated. The pixel (2) was transferred to the substrate (3).

Next, the transferred fine color pixel
(2) After providing the overcoat layer (5) on the top by a conventional method,
The glass substrate on which the transparent electrode (6) made of ITO was previously formed was adhered via an adhesive layer to form one substrate constituting a liquid crystal cell. The transparent electrode (6) can also be formed on the overcoat layer (5).

A liquid crystal was sealed between this substrate and a counter substrate with patterned ITO to form a liquid crystal cell, and polarizing plates were laminated from both sides of the liquid crystal cell to assemble a color LCD. The performance of this color LCD was far superior to that of a color LCD using a color filter by a conventional printing method.

Example 2 A partially cross-linked polyvinyl alcohol film was stretched 6 times in the machine and transverse directions under heating, and then heat-set so as not to impair the shrinkability to obtain a heat-shrinkable transfer sheet (1a). It was
It is also possible to employ a method of mechanically fixing with a frame, omitting heat fixing.

After printing the magnified black matrix layer (4a) on the transfer sheet (1a) using an ink containing a sublimable dye, R, G and B were also printed using the ink containing a sublimable dye. The magnified color pixels (2a) were sequentially printed. The size of each enlarged color pixel (2a) was set to 300 μm square.

The first transfer base material obtained as described above was kept in a heating atmosphere and heat-shrinked to 1/6 in each of the vertical and horizontal directions to obtain the size before stretching. As a result, the target size (each 50
A second transfer base material was obtained in which fine color pixels (2) (and fine black matrix layer (4)) having a (μm angle) were formed.

A substrate (3) having a sublimable dye-accepting ability coated with chitin or silicon-modified polyvinyl alcohol on the surface of a glass plate was prepared, and the second transfer obtained above was applied to the substrate (3). The base material for heat treatment was heat-treated for about 3 minutes at a temperature of about 120 ° C. in a state where the base materials were adhered and laminated. As a result, the fine color pixels (2) formed on the second transfer base material were transferred to the base material (3) side.

Next, an overcoat layer (5) was provided on the fine color pixel (2) by a conventional method, and further a transparent electrode (6) made of ITO was formed.

Using this as one of the substrates constituting the liquid crystal cell, liquid crystal is sealed between the substrate and the counter substrate with patterned ITO to form a liquid crystal cell, and polarizing plates are laminated from both sides of the liquid crystal cell. Then, a color LCD was assembled. The performance of this color LCD was far superior to that of a color LCD using a color filter by a conventional printing method.

[0044]

In the present invention, since the enlarged color pixel (2a) having a size larger than the target size is provided on the transfer sheet (1a) made of a shrinkable sheet, a precision technique of ordinary degree is used. The pattern can be formed accurately without any failure.

Since it is made to shrink after that, the second transfer base material in which the fine color pixels (2) having the target size are formed on the transfer sheet (1) after contraction is used. can get.

Further, 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 high), the fine color pixel (2 ) Has the advantage of increasing the color density, and also has the advantage of reducing color unevenness.

In addition, since the fine color pixels (2) formed on the second transfer base material are transferred to the base material (3), the accurate fine color pixels (2) can be surely obtained. It can be formed on the base material (3), and the degree of freedom in selecting the material of the base material (3) is increased.

As described above, according to the present invention, the drawbacks of the printing method, which has been difficult in the prior art in terms of accuracy, yield, color unevenness, etc., and was not necessarily advantageous as compared with other methods, are completely eliminated. Therefore, the advantage of the printing method that the device / running cost is low in a short process and a large area can be processed can be directly utilized.

Therefore, according to the present invention, mass production and cost reduction of a color filter having an accurate fine colored layer can be achieved.

[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]

(1a) ... Transfer sheet composed of shrinkable sheet, (1) ... Transfer sheet after shrinking, (2a) ... Enlarged color pixel, (2) ... Fine color pixel, (R) ... Red pixel, (G )… Green pixel, (B)…
Blue pixel, (3) ... Base material, (4a) ... Black matrix layer, (4) ... Fine black matrix layer, (5) ... Overcoat layer, (6) ... Transparent electrode

Claims (5)

[Claims] 1. A first transfer base comprising a transfer sheet (1a) made of a shrinkable sheet and enlarged color pixels (2a) having a size larger than a target size and made of transferable ink. material. 2. The transfer base material according to claim 1, wherein the transferable ink is an ink containing a sublimable dye. 3. A shrinkage product of the first transfer base material according to claim 1, wherein fine color pixels (2) having a target size are formed on the transfer sheet (1) after shrinkage. Second transfer base material. 4. A first transfer base material having a magnified color pixel (2a) having a size larger than a target size and having a transferable ink provided on a transfer sheet (1a) made of a shrinkable sheet. By contracting, a second transfer base material having fine color pixels (2) having a target size formed on the contracted transfer sheet (1) is obtained, and then the second transfer base material is obtained.
Fine color pixel formed on the base material for transfer
A method for producing a color filter, which comprises transferring (2) to a substrate (3) side. 5. The method according to claim 4, wherein the transferable ink is an ink containing a sublimable dye.