JPH10123315A - Production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing color filters using an ink jet method which allows the selection of ink regardless of the critical surface tension of a substrate surface and inexpensively produces the color filters. SOLUTION: This process for producing the color filters includes a stage for forming patterns of black matrices (hereafter described as BM) 3 on the transparent substrate and a stage for applying the colored ink 4 in the spacings between the patterns of the BM 3. The critical surface tension in the spacing parts between the patterns of the BM 3 in this process is >=35dyne/cm and the critical surface tension of the BM 3 is >=5 to <=35dyne/cm. The colored ink 4 has the surface tension at 25 deg.C larger by 10dyne/cm than the critical surface tension of the BM 3 layers and have a viscosity of <=15cps. The colored ink is applied in the spacings between the patterns of the BM 3 by the ink jet printing method.

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 of a color liquid crystal display used in a color television, a personal computer, and the like, and more particularly, to a method for manufacturing a liquid crystal color filter using an ink jet printing method.

[0002]

2. Description of the Related Art In recent years, with the development of personal computers, especially portable personal computers, the demand for liquid crystal displays, especially color liquid crystal displays, has been increasing. However, cost reduction is necessary for further widespread use, and in particular, cost reduction of a color filter having a high specific gravity is required.

Conventionally, various methods have been tried to satisfy the above requirements while satisfying the required characteristics of the color filter, but no method has yet been established which satisfies all the required characteristics.

[0004] The most widely used dyeing method is to first form a water-soluble polymer material as a material for dyeing on a glass substrate and pattern it into a desired shape by a photolithography process. The obtained pattern is immersed in a dyeing bath to obtain a colored pattern. By repeating this three times, R.I. G. FIG. A color filter of B is formed.

In the pigment dispersion method, which has recently been replaced by the dyeing method, a photosensitive resin in which a pigment is dispersed is first formed on a substrate, and the photosensitive resin is patterned to obtain a monochromatic pattern, and this process is repeated three times. As a result, R. G. FIG. A color filter layer of B is formed.

In the electrodeposition method, first, a transparent electrode is patterned on a substrate, immersed in an electrodeposition coating solution containing a pigment, a resin, and an electrolytic solution to electrodeposit a first color. Repetition R times G. FIG. A color filter layer of B is formed, and finally baking is performed to form a color filter.

In still another method, a pigment is dispersed in a thermosetting resin, and printing is repeated three times. G. FIG.
After separately applying B, the resin is thermally cured to form a colored layer.

In each of these methods, R. G. FIG. It is necessary to repeat the same process three times in order to color the three colors B, resulting in a problem that the cost increases and the number of processes decreases the yield. In the electrodeposition method, since the pattern that can be formed is limited, it is difficult to apply the current technology to a TFT. Further, the printing method is not suitable for forming a fine-pitch pattern due to poor resolution.

To make up for these drawbacks, Japanese Patent Application Laid-Open No.
9-75205, JP-A-63-235901, JP-A-1
There are proposals such as -217320, but they are not always sufficient.

Japanese Patent Application Laid-Open No. Hei 6-347637 proposes a method of forming an ink by an ink jet printing method using an ink having a surface tension between the critical surface tension of a partition pattern (black matrix) and the critical surface tension of a substrate. However, in this method, it is necessary that the ink is separated from both the partition pattern and the substrate by 5 dyne / cm or more, and the range of ink selection is narrowed, and a color filter with good color characteristics may not be manufactured in some cases.

[0011]

SUMMARY OF THE INVENTION According to the present invention, the manufacturing process can be shortened by using the ink jet printing method while satisfying the required characteristics of the conventional color filter, such as heat resistance, solvent resistance and resolution. It is an object of the present invention to provide a method for manufacturing a color filter at low cost. According to the present invention, the ink can be selected independently of the critical surface tension of the substrate surface.

[0012]

According to the present invention, there is provided a method for producing a color filter, comprising the steps of forming a black matrix pattern on a transparent substrate, and applying a colored ink to a gap between the black matrix patterns. The critical surface tension of the gap portion of the black matrix pattern is 35 dyne / cm or more, and the critical surface tension of the black matrix is 5 dyne / cm or more.
5 dyne / cm or less;
A color filter having a surface tension at 10 ° C. higher than the critical surface tension of the black matrix layer by 10 dyne / cm or more and a viscosity of 15 cp or less, and applying a color ink to gaps of the black matrix pattern by an inkjet printing method. And a method for producing the same.

The present invention also provides a method of manufacturing a color filter, comprising the steps of forming a pattern of a black matrix on a transparent substrate, and applying a color ink to a gap between the black matrix patterns. Forming a transparent organic layer having a critical surface tension of 35 dyne / cm or more; and forming a critical surface tension of 5 dyne / cm or more and 35 dyne on the transparent organic layer.
/ Cm or less in a pattern, and the surface tension at 25 ° C. is 10 dyne / cm higher than the critical surface tension of the black matrix layer.
And a step of applying an ink to the gaps of the black matrix layer by ink-jet printing using a large colored ink having a viscosity of 15 cp or less.

The method of manufacturing these color filters is as follows:
It is used as one step of a method for manufacturing a liquid crystal display device.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent substrate used in the present invention may be a glass substrate generally used as a substrate for a liquid crystal, but the necessity of transparency, mechanical strength, etc. as a liquid crystal color filter is given. It is not limited to a glass substrate as long as it has.

The critical surface tension of the transparent substrate surface is 35 d
If it is yne / cm or more, a black matrix pattern may be formed directly on the surface of the transparent substrate, but it is more preferable to form a transparent organic layer on the surface of the transparent substrate. By forming the transparent organic layer, the uniformity of the surface is improved, the variation when the colored ink is applied is reduced, and the adhesion of the colored ink (after curing) is improved. Further, it is preferable that the transparent organic layer has an ink absorbing property, because the fixing property of the ink is further improved.

As the transparent organic layer, 35 dyne / cm
What is necessary is to have the above critical surface tension, and specifically, 6 nylon, 6,6 nylon, 11 nylon, polyethylene terephthalate, polyvinyl chloride, polyvinylidene chloride, polymethyl acrylate, polyethyl acrylate, polypropylene, Chloroprene, polyvinyl alcohol,
Polysiloxane or the like is used.

The material and the forming method of the black matrix pattern are not limited as long as the critical surface tension of the black matrix after formation is 5 dyne / cm or more and 35 dyne / cm or less, and a non-photosensitive material is used. Although it can be formed by using a photosensitive material containing a photo-curable resin and a black pigment, it is preferable to form by a coating, exposure and development process.

As the photo-curable resin, for example, a positive type photosensitive silicon compound in which a light irradiation part is solubilized is used. Specifically, for example, an alkali-soluble siloxane,
Examples thereof include those obtained by adding naphthoquinonediazide to silsesquioxanone or the like, those obtained by adding naphthoquinonediazide esters to a silicon-modified novolak resin, silicon-modified acrylic resins, and polysilanes.
In addition, general acrylate-based, polyimide-based resins and the like can also be used.

Examples of black pigments for exhibiting light-shielding properties include carbon black and Ni / Ti / Fe / Co.
/ Sn and the like, an organic black pigment, a mixture of two or more kinds of pigments such as blue, purple, yellow, and red, and a mixture thereof. These are materials, contents, so that they have the necessary degree of transparency in the ultraviolet region for photosensitivity.
It is desirable to appropriately adjust the mixing ratio and the like and to disperse in the photocurable resin.

In order to apply the photosensitive material for a black matrix onto a substrate surface, any coating method such as spin coating, roll coating, bar coating, spray coating, and dip coating can be used.

After that, a black matrix pattern is formed by exposing using an exposure apparatus having a wavelength matching the sensitivity of the photocurable resin and a mask having a predetermined pattern, and then developing the black matrix pattern. The substrate surface (or the transparent organic layer formed on the substrate surface) is exposed.

Next, using an ink jet printer,
For example, R, G, and B colored inks are applied to the gaps between the black matrix patterns to be pixels, and the inks are dried as necessary.

As the coloring ink, as described above, 25 ° C.
If the surface tension is higher than the critical surface tension of the black matrix layer by 10 dyne / cm or more and the viscosity is 15 cp or less, both dye-based and pigment-based can be used. Usually, those having a critical surface tension of 35 to 65 dyne / cm at 25 ° C. are used.

As the ink jet printing machine, a bubble jet type using an electric transducer or a piezo jet type using a piezoelectric element can be used as an energy generating element, and a coloring area and a coloring pattern are arbitrarily set. be able to.

After drying or curing the colored ink, a protective layer is formed if necessary. As the protective layer, a resin material of photo-curing type / thermo-curing type or combined use of light and heat, an inorganic film formed by vapor deposition, sputtering, or the like can be used, and has transparency when a color filter is used. Any material that can withstand the ITO forming process, the alignment film forming process, and the like can be used.

Next, FIG. 1 shows an example of a TFT color liquid crystal panel incorporating the color filter of the present invention.

A color liquid crystal panel is generally formed by laminating a color filter substrate and a counter substrate to face each other and sealing a liquid crystal compound between the two substrates. TFTs (not shown) and transparent pixel electrodes are formed in a matrix inside one substrate of the liquid crystal panel.
Further, on the inside of the other substrate, each color of RGB of the color filter is arranged at a position facing the pixel electrode, and a transparent counter electrode is formed thereon. Further, an alignment film is formed in the plane of both substrates, and rubbing the alignment film allows liquid crystal molecules to be aligned in a certain direction.

A polarizing plate is adhered to the outside of each glass substrate, and the liquid crystal compound is filled in the gap (about 2 to 5 μm) between these glass substrates. In addition, a combination of a fluorescent lamp (not shown) and a scattering plate (not shown) is generally used as the backlight, and the display is performed by making the liquid crystal compound function as an optical shutter that changes the transmittance of the backlight light. I do.

[0030]

The present invention will be described below in detail with reference to examples.

Example 1 Glass substrate (Corning 70)
59) on top of polyethyl acrylate (critical surface tension 35
dyne / cm) with a toluene solution (solid content: 10%) using a dip coating method (pulling speed: 100 nm /
min film thickness: 80 nm) to form a transparent organic layer.

On this transparent organic layer, a negative type black resist material (a phenol novolak resin resist mixed with carbon black) is applied by a spin coater to a film thickness l.
It was coated to a thickness of μm, exposed using a predetermined pattern mask, and developed to obtain a black matrix having a predetermined pattern shape. The critical surface tension of this black matrix was 21 dyne / cm.

Thereafter, using an ink jet recording apparatus, a pigment ink having an ink viscosity of 9 cp at 25 ° C. and a surface tension of 42 dyne / cm (for example, CI Pigment Red 177 as a pigment and a styrene-acrylic acid copolymer as a resin) Of the black matrix with RGB using an ammonium salt of isopropyl alcohol or the like as a solvent, and then 90 ° C., 5 m
In-ink drying was performed.

Next, an ITO electrode was formed by a sputtering method.

Observation of the thus prepared color filter for liquid crystal with an optical microscope confirmed that the color filter had no color mixture and had uniform light transmission and no pixel defects.

Example 2 In Example 1, a transparent organic film was formed of nylon 11 having a critical surface tension of 43 dyne / cm, and a black matrix was formed using a black pigment (MCF-88 manufactured by Mitsubishi Chemical) and water-repellent silicon (modified with silicon). Acrylic resin) is formed of a negative photosensitive resin (critical surface tension 25 dyne / cm). The ink has a viscosity at 25 ° C. of 15 cp and a surface tension of 50 dyne / cm.
(For example, CI Pigmen as a pigment)
Example 1 was repeated except that t Green 36 and the same resin and solvent as in Example 1 were used) to produce a color filter for a liquid crystal. No color filters were obtained.

Example 3 In Example 1, a transparent organic layer was formed of nylon 11 having a critical surface tension of 43 dyne / cm, and a black matrix was formed with a black pigment (MCF-88 manufactured by Mitsubishi Chemical) and a water-repellent fluorine compound (Asahi Glass) Company
It is formed of a negative photosensitive resin containing (Cytop CTL) (critical surface tension 10 dyne / cm), and has a viscosity of 9 cp at 25 ° C. and a surface tension of 42 dyne as an ink.
/ Cm of pigment ink (for example, CI Pig as a pigment)
Example 1 was repeated except that the same resin and solvent as those of Example 1 were used) to produce a color filter for liquid crystal. No color filters were obtained.

Comparative Example 1 In Example 1, except that the transparent organic layer was formed of poly (propylene fluoride) having a critical surface tension of 16 dyne / cm and the black matrix was formed of a black pigment-containing acrylate compound (43 dyne / cm). A color filter for liquid crystal was prepared by repeating Example 1, but color mixture was found between adjacent pixels, pixel defects were present, and light transmittance was non-uniform.

Comparative Example 2 A color filter for liquid crystal was prepared by repeating Example 1 except that the transparent organic layer was formed of polyethylene having a critical surface tension of 31 dyne / cm. Color mixing was observed.

Comparative Example 3 The procedure of Example 3 was repeated except that the mixing ratio of the water-repellent fluorine compound (Teflon AF manufactured by duPont) contained in the material forming the black matrix was changed to form a black matrix having a different critical surface tension. A color filter was prepared in the same manner as in Example 3.

As a result, when the critical surface tension of the black matrix was in the range of 5 dyne / cm or more and 35 dyne / cm or less, no color mixing was observed between adjacent pixels. Critical surface tension of black matrix is 3
When it was 5 dyne / cm or more, the ink got on the black matrix and color mixing occurred. On the other hand, when the critical surface tension of the black matrix was 5 dyne / cm or less, the ink did not sufficiently penetrate into the lower corner of the black matrix, and a white spot phenomenon was observed.

Comparative Example 4 A color filter was prepared in the same manner as in Example 2 except that various inks having different critical surface tensions were used. As a result, with the ink having a difference from the critical surface tension of the black matrix of less than 10 dyne / cm, the ink got on the black matrix and color mixing occurred. on the other hand,
10 dyne from the critical surface tension of black matrix
Ink having a critical surface tension greater than / cm did not cause color mixing.

[Comparative Example 5] In Example 1, an ink having a viscosity of 20 cp at 25 ° C was used as an ink.
An attempt was made to color in the same manner as in Example 1, but no stable ejection was obtained from the inkjet nozzle. Ink was ejected with a lower viscosity.
The ink did not sufficiently penetrate to the corners of the pixel portion of the black matrix gap. When the viscosity became 15 cp or less, the ink permeated to the corner of the pixel portion in the gap of the black matrix.

[0044]

According to the present invention, the manufacturing process can be shortened by using the ink jet printing method while satisfying the required properties of the conventional color filter, such as heat resistance, solvent resistance, and resolution, and the cost can be reduced. And a method for producing a color filter.

According to the present invention, since the ink can be selected regardless of the critical surface tension of the substrate surface, the range of ink selection can be widened and a color filter having excellent color characteristics can be produced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal panel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Transparent organic layer 3 Black matrix 4 Colored ink layer 5 Protective layer 6 Common electrode 7 Alignment film 8 Liquid crystal compound 9 Alignment film 10 Glass substrate 11 Polarizer 12 Polarizer 13 Pixel electrode 14 Backlight

Claims (4)

[Claims] 1. A method for manufacturing a color filter, comprising: forming a pattern of a black matrix on a transparent substrate; and applying a color ink to a gap between the black matrix patterns. The tension is 35 dyne / cm or more, and the critical surface tension of the black matrix is 5 dyne.
/ Cm or more and 35 dyne / cm or less, wherein the colored ink has a surface tension at 25 ° C of 10 dyne / cm2 more than the critical surface tension of the black matrix layer.
A method for producing a color filter, wherein a color ink is applied to gaps of a black matrix pattern by an inkjet printing method, the coloring ink having a viscosity of at least 15 cm and a viscosity of 15 cp or less. 2. A method for manufacturing a color filter, comprising the steps of: forming a pattern of a black matrix on a transparent substrate; and applying a colored ink to a gap between the black matrix patterns, wherein a critical surface is formed on the entire surface of the transparent substrate. Tension is 35 dyne
Forming a transparent organic layer having a critical surface tension of 5 dyne / c or more on the transparent organic layer.
forming a black matrix layer having a thickness of not less than m and not more than 35 dyne / cm in a pattern; using a colored ink having a surface tension at 25 ° C. of at least 10 dyne / cm higher than the critical surface tension of the black matrix layer and a viscosity of not more than 15 cp. Applying the ink to the gaps between the black matrix layers by an inkjet printing method. 3. The method according to claim 1, wherein the formation of the black matrix pattern is performed by exposure using a black photosensitive material. 4. A method for manufacturing a liquid crystal display device, comprising the method for manufacturing a color filter according to claim 1 as one step.