JP2002365423A - Color filter and method for manufacturing the same, liquid crystal element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a color filter with a flat surface by an inkjet method. SOLUTION: Partition walls 2 with an ink-repelling property are formed on a substrate 2. Hardening type ink 3 is imparted by the inkjet method so as to form coloring parts 4. Subsequently a resin composition layer 5 is formed on the full surface of the substrate, the coloring parts 4 are exposed and the color filter with the flat surface is formed.

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 suitably used for a color liquid crystal display used in a color television, a personal computer, a pachinko game machine, etc. by an ink jet method, and a method for manufacturing the same. The present invention relates to a manufactured color filter and a liquid crystal element formed using the color filter.

[0002]

2. Description of the Related Art In recent years, with the development of portable personal computers and small liquid crystal televisions, the demand for liquid crystal displays has been increasing. Above all, the growth of color liquid crystal displays is remarkable. However, for further widespread use, it is necessary to reduce the cost of the liquid crystal display. In particular, there is an increasing demand for reducing the cost of a color filter having a high cost.

A color filter is usually provided on a transparent substrate with a plurality of colored portions having different light transmittances (generally, R (red), G (color)).
(Green) and B (blue)], and the adjacent colored portions are shielded from light by a light-shielding layer such as a black matrix or a black stripe in order to increase display contrast.

The light-shielding layer is usually formed by etching a metal chromium vapor deposition film or a sputtering film. In addition, a transparent conductive base film made of ITO or the like is formed on the entire surface of the substrate, and a colored portion is formed thereon by a pigment dispersion method or the like, and an electrodeposition method is performed using the ITO film between the colored portions. Forming method, forming a photosensitive black resin layer on the substrate,
A method of patterning by photolithography is also used.

[0005] As a method of forming a colored portion, a method of using a photosensitive resin in which a pigment is dispersed, a method of patterning and dyeing a dyeable resin layer using photolithography, and a method of patterning an electrode on a substrate are described. And a method of electrodepositing a dye on the electrode, a method of printing, and the like. Further, as a low-cost method, there is a method using an inkjet method.

[0006] As a method using an ink jet system, a method of forming an ink absorbing layer having an ink absorbing property on a substrate, applying an ink and coloring the ink to form a colored portion, and a method of forming a plurality of openings on the substrate. There is a method of forming a partition having the following formula, and applying a curable ink to the opening of the partition to cure the ink to form a colored portion. In the latter case, the process is shorter and advantageous.

[0007]

However, in the above-described method of manufacturing a color filter in which a curable ink is applied to the openings of the partition walls on the substrate to form a colored portion by the ink-jet method, each of the adjacent openings has In order to prevent so-called color mixing, in which curable inks of different colors to be applied are mixed with each other beyond the partition walls, the partition walls are formed of a material having ink repellency. Therefore, when the curable ink is applied to the opening, the surface of the cured colored portion becomes spherical due to the action of the surface tension of the curable ink and the surface tension of the partition walls. That is, in the opening,
This is a state in which a difference in film thickness occurs between the central portion and the peripheral portion of the colored portion, and color unevenness occurs in the colored portion. In addition, since the surface is not smooth, when the liquid crystal element is assembled, the image quality is reduced. Specifically, an active matrix type liquid crystal element requires a flatness of 0.3 μm or less, and a simple matrix type liquid crystal element requires a flatness of 0.1 μm or less.

To solve the problem of the surface step, there is a method of reducing the step by applying a flattening layer on the colored portion. However, if the step on the surface of the colored portion is large, the flattening layer becomes thick. It is necessary to form a film or a multilayer, and the transmittance is reduced. In addition, there is a problem that costs are high,
There is a demand for a color filter that does not use a flattening layer.

An object of the present invention is to manufacture a color filter having a flat surface and no flattening layer by a short process by a manufacturing method using an ink jet system, and to provide a color display liquid crystal element having high image quality at a lower cost. To provide.

[0010]

A first aspect of the present invention is a method of manufacturing a color filter having at least a plurality of colored portions on a substrate and partitions separating adjacent colored portions.
A partition having a plurality of openings and having at least an upper surface having ink repellency is formed on the substrate, and a curable ink is applied to each of the openings according to a predetermined coloring pattern by an inkjet method, and cured to cure the colored portion. Is formed, a resin composition layer is formed on the entire surface, and the colored portion is exposed by removing the surface layer to a predetermined depth on the entire surface of the substrate.

In the method of manufacturing a color filter according to the present invention, it is preferable that the removal of the surface layer is performed by polishing.

A second aspect of the present invention is a color filter having at least a colored portion of a plurality of colors and a partition separating an adjacent colored portion on a substrate, which is manufactured by the method of manufacturing a color filter of the present invention. A color filter characterized in that:

In the above color filter of the present invention,
It is preferable that at least one of the partition wall and the resin composition has a light-shielding property and has a protective layer on the colored portion as a preferred embodiment.

A third aspect of the present invention is a liquid crystal element characterized in that liquid crystal is sandwiched between a pair of substrates, and one of the substrates is formed using the color filter of the present invention.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, a curable ink is applied to the opening of a partition wall having ink repellency to form a colored portion, and then a second resin composition layer is laminated on the entire surface of the substrate. The present invention is characterized in that a color filter having high surface flatness is manufactured by removing a surface layer from a surface to a predetermined depth by polishing or the like to expose a colored portion.

Hereinafter, the present invention will be described with reference to embodiments.

FIG. 1 schematically shows the steps of a preferred embodiment of the method for producing a color filter of the present invention. In the figure, 1
Is a substrate, 2 is a partition, 3 is a curable ink, 4 is a colored portion, 5
Denotes a resin composition layer, and 6 denotes a protective layer. 1A to 1E are cross-sectional views corresponding to the following steps (a) to (e), respectively.

Step (a) A partition 2 is formed on a substrate 1. As the substrate 1, a substrate having necessary characteristics such as transparency and strength may be used. In general, glass is used, but plastic can also be used. Further, a black matrix substrate manufactured by patterning a metal thin film or the like in advance may be used.
In this case, when the partition wall 2 and the resin composition layer 5 formed thereon are used as a light shielding layer, formation of a black matrix having a higher OD value can be expected.

In the next step (b), the partition wall 2 is cured with the curable ink 3
This is a member that acts to house the black matrix, and in the present invention, it can be a black matrix that also serves as a light shielding layer. The partition wall 2 according to the present invention has at least an upper surface having ink repellency, and is usually formed of a resin composition. Specifically, a photosensitive resin composition that exhibits ink repellency upon curing is preferable,
Commercially available transparent or black negative or positive photoresists are preferably used. Here, when a transparent photoresist is used, it is expected that the partition walls 2 can be formed with high precision. When a black photoresist is used, a black matrix 2 can be formed. Further, by using a light-shielding resin composition as a resin composition used in the next step (c), a black matrix having a high OD value can be obtained. Can be expected.

In the present invention, the height of the partition 2 is
Higher than the height of the colored portion 4 formed in the next step (c),
When the upper layer of the partition 2 is removed by polishing or the like in the subsequent step (d), it is necessary to use a material that can be removed by the polishing step or the like as the partition 2. Partition wall 2 according to the present invention
Is preferably 0.5 μm in consideration of the partition wall effect.
The above is preferred.

Step (b) The curable ink 3 is applied along a predetermined coloring pattern using an ink jet head (not shown), with the opening of the partition wall 2 as a portion to be colored. Curable ink 3 according to the present invention
Is a curing component such as a resin composition and a colorant (usually R, G,
B) and a solvent component.

The curing components contained in the curable ink 3 include N, N-dimethylolacrylamide, N, N
Acrylamide monomers such as dimethoxymethylacrylamide, N, N-diethoxymethylacrylamide, N, N-dimethylolmethacrylamide, N, N-dimethoxymethylmethacrylamide, N, N-diethoxymethylmethacrylamide A polymer or a copolymer with another vinyl monomer is exemplified. Other vinyl monomers, acrylic acid, methacrylic acid, acrylates such as methyl acrylate and ethyl acrylate, methacrylates such as methyl methacrylate, ethyl methacrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, Hydroxymethyl acrylate, vinyl monomers containing a hydroxyl group such as hydroxyethyl acrylate, and others, styrene, α-methylstyrene, acrylamide, methacrylamide, acrylonitrile, allylamine, vinylamine, vinyl acetate,
And vinyl propionate. In the case of a copolymer of the acrylamide monomer and another vinyl monomer, the acrylamide monomer is used in an amount of 5% by weight or more,
Preferably it is 10 to 90% by weight.

The content of the curing component in the curable ink 3 according to the present invention is preferably 0.01 to 30% by weight, more preferably 0.1 to 10% by weight. When the amount of the curing component is less than 0.01% by weight, the curability becomes insufficient, and when the amount exceeds 30% by weight, problems such as a decrease in inkjet dischargeability and a decrease in stability of the ink itself are caused. May occur, which is not preferred.

Further, when the curing component is photocured, various photocurable resins and photopolymerization initiators may be added.

As the colorant contained in the curable ink 3, any of a dye or a pigment can be used, and the content thereof is 0.5 to 10 with respect to the total weight of the ink.
% By weight is preferred.

Further, in addition to the above-mentioned components, various types of commercially available resins and additives can be used as appropriate for the curable ink 3 as long as they do not cause problems such as sticking in the ink. For example, an acrylic resin, an epoxy resin, or the like can be used.

The curable ink 3 is used by dissolving or mixing the above-mentioned curing component and colorant in a solvent. The solvent used here is preferably water or a combination of water and a water-soluble organic solvent.

The ink jet system used in the present invention includes a bubble jet (registered trademark) type using an electrothermal converter as an energy generating element,
A piezo jet type using a piezoelectric element can be used.

Step (c) The curable ink 3 is subjected to a necessary treatment such as heat treatment or light irradiation, and is cured to form the colored portion 4. Thereafter, the resin composition layer 5 is formed on the entire surface of the substrate. As a method of forming the resin composition layer 5, a method of applying the resin composition precursor solution by a spin coating method, a roll coating method, a dip coating method, or the like is preferable, and thereafter, the resin composition is cured by heat curing or photo curing.

The resin composition used in this step is a material that fills the steps between the colored portion 4 and the surface of the partition 2 and can be removed by polishing or the like in the next step (d). Preferably, the same material as that of the partition wall 2 described in the step (a) is used. In particular, when the partition wall 2 is made light-blocking and the lower layer of the resin composition layer remains on the partition wall 2 when polished, It is desirable to form a light-shielding layer having a high OD value by using a light-shielding material like the partition 2.

Step (d) On the entire surface of the substrate, the surface layer is removed from the surface of the resin composition layer 5 to a predetermined depth to expose the colored portion 4. At this time, the exposed surface of each colored portion 4 is made to have the same area. The resin composition layer 5 may be left on the partition 2 as long as it is removed from the colored portion 4. As a method for removing the surface layer, polishing is preferable, and as an abrasive, a buff or a polishing film is preferably used. By this step, a smooth surface in which the surface of the colored portion 4 is continuous with the surface of the partition wall 2 or the remaining resin composition layer 5 is obtained.

Step (e) If necessary, a protective layer 6 is formed on the colored portion 4 to obtain the color filter of the present invention. As the protective layer 6, a resin composition layer of a photo-curing type, a thermosetting type, or a combination of heat and light, or an inorganic film formed by vapor deposition, sputtering, or the like can be used. In any case, any material can be used as long as it has transparency as a color filter and can withstand the subsequent ITO film forming step, alignment film forming step, and the like.

Next, FIG. 2 is a schematic sectional view of one embodiment of the liquid crystal element of the present invention. The present embodiment is an example in which a TFT type color liquid crystal element is configured using the color filters obtained by the process of FIG. In the figure, 7 is a common electrode, 8,
Reference numeral 13 denotes an alignment film, 9 denotes a liquid crystal, 11 denotes a counter substrate, and 12 denotes a pixel electrode. The same members as those in FIG.

The color liquid crystal element is generally formed by aligning the substrate 1 on the color filter side with the counter substrate 11 and sealing the liquid crystal 9. TFTs (not shown) and pixel electrodes 12 are formed in a matrix inside one substrate 11 of the liquid crystal element. Further, inside the substrate 1 on the color filter side, at a position facing the pixel electrode 12,
The colored portion 4 of the color filter is formed so that R, G, and B are arranged, and a transparent common electrode 7 is formed thereon. Usually, a black matrix is formed on the color filter side, and in this configuration, the partition 2 can be used as well.
In a BM-on-array type liquid crystal element or the like, a black matrix may be formed on the counter substrate 11 side. Further, alignment films 8 and 13 are formed in the plane of both substrates, and the liquid crystal molecules are arranged in a certain direction. These substrates are opposed to each other via a spacer (not shown), are adhered to each other with a sealing material (not shown), and the gap is filled with a liquid crystal 9.

In the case of the transmissive liquid crystal element, the substrate 11 and the pixel electrode 12 are formed of a transparent material, a polarizing plate is adhered to the outside of each substrate, and a fluorescent lamp and a scattering plate are generally combined. The display is performed by using the backlight and using the liquid crystal compound as an optical shutter for changing the transmittance of the backlight. In the case of the reflection type, the substrate 11 or the pixel electrode 12 is formed of a material having a reflection function, or a reflection layer is provided on the substrate 11, a polarizing plate is provided outside the substrate 1, and a color filter is provided. Display is performed by reflecting light incident from the side.

In the liquid crystal device of the present invention, as long as it is constituted by using the color filter of the present invention, it is needless to say that the conventional technique can be used as it is for the other members.

[0037]

(Example 1) A photosensitive resin composition comprising an acrylic polymer shown below was spin-coated on an alkali-free glass (200 mm square, 1.1 mm thick) whose surface was polished, and was applied at 90 °. A prebaking treatment was performed for 20 minutes to form a photosensitive resin composition layer having a thickness of 0.5 μm.

[Composition of Photosensitive Resin Composition] Acrylic copolymer (copolymer of the following monomer) 10.0 parts by weight ・ Methyl methacrylate 5.0 parts by weight ・ Hydroxymethyl methacrylate 3.0 parts by weight ・ N -Methylol acrylamide 2.0 parts by weight Triphenylsulfonium triflate ("TPS-105" manufactured by Midori Kagaku Co., Ltd.) 0.3 parts by weight Ethyl cellosolve 89.7 parts by weight

Next, the photosensitive resin composition layer is subjected to pattern exposure through a photomask having a partition pattern as an opening, heat-treated on a hot plate at 120 ° C. for 1 minute, and immersed in a NaOH aqueous solution of pH = 12. Then, the unexposed portion was removed. Thereafter, the resultant was heated in an oven at 230 ° C. for 30 minutes, and was completely cured to form a partition.

Next, a curable ink having the following composition is discharged from the ink jet head to each opening of the partition wall along a predetermined coloring pattern, and dried at 90 ° C. for 20 minutes, and subsequently at 230 ° C. for 30 minutes. Heat treatment,
The ink was cured to form a colored portion.

[Composition of Curable Ink] Acrylic copolymer (copolymer of the following monomer) 10.0 parts by weight ・ Methyl methacrylate 5.0 parts by weight ・ Hydroxymethyl methacrylate 3.0 parts by weight ・ N-methylol Acrylamide 2.0 parts by weight R, G, B dyes 5.0 parts by weight Ethylene glycol 20.0 parts by weight Deionized water 65.0 parts by weight

The maximum thickness of the obtained colored portion was 1.8 μm, and the difference in thickness from the partition wall was about 1.3 μm.

A black resist (“V-259VK” manufactured by Nippon Steel Chemical Co., Ltd.) was applied on the colored portion by a spin coater so as to have a thickness of 1.5 μm, and dried at 100 ° C. for 20 minutes.

Next, a polishing tape (# 100) using alumina powder was used as a polishing condition,
Polishing was performed from the surface of the black resist layer under a pressure of kg / cm ² to obtain a color filter of the present invention. In the polishing, the black resist on the colored portion was removed, and the upper layer of the colored portion was also polished so that the exposed portion had the same area in each colored portion. As a result, the lower layer of the black resist layer remained on the partition walls, and the surface step was 0.15 μm.

When a liquid crystal device was manufactured using the obtained color filter, a high-definition color display was possible.

Example 2 A color filter was produced in the same manner as in Example 1 except that the partition walls were formed using a black resist (“V-259VK” manufactured by Nippon Steel Chemical Co., Ltd.). .15 μm, which was a good color filter. Further, when a liquid crystal element was produced using this color filter as in Example 1, high-definition color display was possible.

Comparative Example 1 On the glass substrate used in Example 1, a black resist (“V-259V” manufactured by Nippon Steel Chemical Co., Ltd.) was used.
K ") was formed to a film thickness of 1 μm, pattern-exposed, developed, and dried at 90 ° C. for 20 minutes to form a black matrix also serving as a partition.

The same curable ink as in Example 1 was applied to the opening of the black matrix along the predetermined coloring pattern in the same amount as in Example 1, dried at 90 ° C. for 20 minutes, and dried.
The composition was cured by a heat treatment at 30 ° C. for 30 minutes to form a colored portion. The maximum thickness of the colored portion was 1.7 μm, and the difference in thickness from the black matrix was 0.7 μm.

Next, a two-pack type thermosetting resin composition ("Optomer SS-6688" manufactured by Nippon Synthetic Rubber Co., Ltd.), which is usually used as a protective layer of a color filter, is applied to a thickness of 2 .mu.m. After pre-baking at 200 ° C. for 30 minutes, heat treatment is performed at 200 ° C. for 30 minutes, and cured,
A protective layer was formed. The step on the surface of the obtained color filter was 0.4 μm. That is, although the protective layer was formed, it was found that the surface smoothness was poor as compared with Examples 1 and 2 in which the protective layer was not formed.

[0050]

As described above, according to the present invention,
It is possible to obtain a smooth color filter in which the surface step is significantly reduced compared to the conventional art, and it is not necessary to use a flattening layer, or even if it is used, a thin flattening layer is sufficient. Accordingly, a color filter having high transparency is provided, and a liquid crystal element having high definition and excellent color display characteristics can be provided at lower cost.

[Brief description of the drawings]

FIG. 1 is a process chart of one embodiment of a method for manufacturing a color filter of the present invention.

FIG. 2 is a schematic sectional view of one embodiment of the liquid crystal element of the present invention.

[Description of Signs] 1 Substrate 2 Partition wall 3 Curable ink 4 Colored part 5 Resin composition layer 6 Protective layer 7 Common electrode 8 Alignment film 9 Liquid crystal 11 Opposite substrate 12 Pixel electrode 13 Alignment film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09F 9/00 342 G09F 9/30 349A 5G435 9/30 349 349C 9/35 9/35 B41J 3/04 101Z (72) Inventor Katsuhiro Shirota 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yoshihisa Yamashita 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Invention Person Koichiro Nakazawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. BA43 CA19 CA24 ED03 ED15 HA07 HA08 5G435 AA04 AA17 BB12 BB15 CC09 CC12 GG12 KK05 KK07 KK10 LL04 LL08

Claims (6)

[Claims] 1. A method for manufacturing a color filter, comprising at least a plurality of colored portions on a substrate and partitions separating adjacent colored portions, wherein the substrate has a plurality of openings and at least an upper surface has repellency. Forming a partition having an ink property, applying a curable ink by an inkjet method along a predetermined coloring pattern to each opening, and curing to form a colored portion, then form a resin composition layer on the entire surface, A method for manufacturing a color filter, wherein the colored portion is exposed by removing a surface layer to a predetermined depth over the entire surface of the substrate. 2. The method according to claim 1, wherein the removal of the surface layer is performed by polishing. 3. A color filter having at least a colored portion of a plurality of colors and a partition separating adjacent colored portions on a substrate, wherein the color filter is manufactured by the method of manufacturing a color filter according to claim 1. A color filter characterized by the following. 4. The color filter according to claim 3, wherein at least one of the partition and the resin composition is light-shielding. 5. The color filter according to claim 3, further comprising a protective layer on the colored portion. 6. A liquid crystal device comprising a pair of substrates sandwiching a liquid crystal, and one substrate comprising the color filter according to claim 3.