JPH06130219A - Color filter and its production - Google Patents

Abstract

PURPOSE:To obtain a color filter with light shielding parts satisfying all of light shielding property, sensitivity to exposure and flatness independently of each other. CONSTITUTION:This color filter has at least a transparent substrate and a colored pattern part with picture elements having plural colors formed at central prescribed positions on the substrate and light shielding parts formed between the picture elements with photosensitive paste consisting essentially of a coloring component, a photosensitive compsn., a polymer insoluble in an alkali developer and a solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter suitable for a color liquid crystal display device such as a color liquid crystal television and a color liquid crystal display for a computer, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Color filters for color liquid crystal display devices have been put into practical use by a method such as a dyeing method, a printing method, a photolithography method, an electrodeposition method, and the like. Has been obtained. At this time, in order to improve the display quality of the pixels, a method of forming a light shielding portion between the pixels has been devised. By providing the light-shielding portion, it is possible to prevent light from leaking in a portion where a voltage is not applied between the transparent electrodes, that is, a portion which does not contribute to display, and to enhance color contrast. Further, in the case of the active matrix method, there is also an effect of preventing malfunction of the switching element due to light.

Conventionally, various methods for forming this light shielding portion have been proposed. The first is a method of forming a chromium vapor deposition film or a sputtering film on a glass substrate and patterning it by etching. In this case, it is essential to produce a chromium film uniformly and without defects such as pinholes, and patterning requires numerous processes such as resist coating, exposure, development, baking, etching, and resist stripping. .

The second is a method of applying an ink or paste colored with a black pigment with a printing machine, a spinner, a roll coater or the like, and patterning by mask exposure, but sufficient light shielding property, dimensional accuracy and flatness are obtained. It is difficult to realize.

Compared with these conventional methods, the backside exposure method is promising because it is considered to have excellent dimensional accuracy and flatness (for example, JP-A-1-138530 and JP-A-3-209203). JP-A-3-284704
Issue Bulletin). That is, the backside exposure method means that pixels are formed on a transparent substrate in advance, and a negative type photosensitive coloring paste in which a light-shielding pigment is dispersed is applied on the entire surface, and then each pixel is used as a mask, and the transparent substrate side is used. This is a method of forming a light-shielding portion in the gap between each pixel by exposing from the (back side). At this time, since the frame light-shielding portion (light-shielding frame) is formed adjacent to the outside of the colored pattern portion including the pixel and the light-shielding portion, a frame-processing mask can be used. The frame-processing mask is a mask that transmits light only to the central portion, that is, a mask that transmits light only to the central colored pattern portion and a frame portion having a predetermined width outside the central colored pattern portion.

However, a light-shielding portion which simultaneously satisfies all the characteristics such as light-shielding property, exposure sensitivity and flatness has not been obtained by such a method. That is, in order to make the light-shielding property sufficient, the coating film must be thickened or the coloring component in the paste must be increased. In either method, the exposure sensitivity decreases, and the required film thickness and light-shielding property It is not possible to form a light shielding part. That is, even if the exposure is performed for a long time, the film thickness is insufficient and the surface irregularities are severe, resulting in poor flatness. Similarly, even if an attempt is made to increase the light-shielding property, the ultraviolet rays are attenuated by the coloring component,
There was a limit to the light blocking effect.

[0007]

The present invention was devised in view of the above-mentioned drawbacks of the prior art, and its object is to satisfy all of the light-shielding properties, exposure sensitivities, and flatness at the same time regardless of each other. It is an object of the present invention to provide a color filter having a light-shielding portion and a manufacturing method thereof.

[0008]

The object of the present invention is as follows.
This is achieved by adopting the following configuration.

(1) A color filter having at least a transparent substrate and a colored pattern portion having pixels of a plurality of colors formed at predetermined positions on the central side of the transparent substrate and a light-shielding portion formed between the pixels. 2. The color filter, wherein the light-shielding portion is composed of a cured product of a photosensitive paste containing a coloring component, a photosensitive composition, an alkali developer insoluble polymer and a solvent as main components.

(2) A method of manufacturing a color filter including the following steps (A) to (D).

(A) a step of forming a colored pattern portion having a plurality of color pixels and light-shielding portion forming gaps at a predetermined position on the central side of the transparent substrate, (B) a coloring component on the transparent substrate, A step of applying and drying a photosensitive paste containing a photosensitive composition, an alkali developer insoluble polymer and a solvent as main components, and (C) exposing from the back surface side of the transparent substrate to form a coating film in a gap portion for forming a light shielding portion And (D) developing and removing the coating film on the pixel.

(3) The coloring component in the photosensitive paste is an organic pigment or an inorganic pigment, and the alkali developer insoluble polymer is a vinyl polymer.
(1) The color filter described.

(4) The coloring component in the photosensitive paste is an organic pigment or an inorganic pigment, and the alkali developer insoluble polymer is a vinyl polymer.
(2) A method for manufacturing the color filter described above.

The present invention will be described in detail below.

The transparent substrate in the present invention is not particularly limited, but glass or transparent plastic is preferably used.

The color filter according to the present invention has a colored pattern composed of pixels of a plurality of colors and a light shielding portion at a predetermined position on the center side of the transparent substrate. The color of each pixel is usually
The shape of each pixel is red, blue, and green, and the shape of each pixel is not particularly limited, but a stripe shape, a mosaic shape, or the like is common. In addition, between each pixel is usually 10
A space of about 20 μm is provided, and a light shielding part is formed in this space.

In the present invention, the photosensitive paste used for forming the light-shielding portion contains a coloring component, a photosensitive composition, an alkali developer insoluble polymer and a solvent as main components.

Coloring components used in the photosensitive paste include organic pigments such as carbon black, phthalocyanine type, azileke type, condensed azo type, quinacridone type, anthraquinone type, perinone type, perylene type, ultramarine blue, navy blue and cobalt blue. Inorganic pigments such as can be used. These pigments can be used alone or in combination of two or more.

The ratio of the coloring component in the photosensitive paste is 1
-30% by weight is preferable, and more preferably 3-10% by weight. If it is less than 1% by weight, the optical density is insufficient and the function as a light shielding portion is small. On the other hand, if it exceeds 30% by weight, the fluidity of the paste is deteriorated and it becomes difficult to form a uniform coating film on the glass substrate.

The photosensitive composition used for the photosensitive paste is one that can form a pattern image by curing by ultraviolet exposure and developing to remove the unexposed area. That is, in the present invention, a photosensitive composition that is soluble in an alkaline developer is used. Examples of such a photosensitive composition include a resin having a photosensitive group such as cinnamic acid-based resin, or a resin having an acid group such as a carboxyl group such as cellulose-based, acrylic-based, vinyl-based, urethane-based, and ethylenic Monomers or oligomers having a saturated group, and those containing a photoinitiator as a main component can be used. Among these, a particularly preferable resin is a resin containing acrylic acid as an acrylic copolymerization component, or a part of acrylic acid as an acrylic copolymerization component becomes an ethylenically unsaturated group by introducing a glycidyl group. A resin such as a resin, a polyfunctional monomer such as trimethylolpropane trimethacrylate, a functional oligomer such as an epoxy diacrylate, and a photoinitiator such as “IRGACURE” 907 and “IRGACURE” 369 (manufactured by Ciba Geigy). A mixture containing the same can be mentioned.

The proportion of the photosensitive composition in the photosensitive paste is preferably 1 to 50% by weight, more preferably 5%.
Is about 20% by weight. If it is less than 1% by weight, the exposure sensitivity becomes low and it is difficult to form a pattern. On the other hand, when it exceeds 50% by weight, other components are reduced, so that insufficient optical density and poor fluidity are likely to occur.

The alkali developer insoluble polymer used in the photosensitive paste has the property of not being dissolved in a developer consisting of an aqueous solution of sodium carbonate, caustic soda, caustic potash, ethanolamine, etc., and has an affinity for coloring components. Insensitive polymers are preferred. Examples of such an alkali developer insoluble polymer include vinyl polymers such as polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, and various modified products thereof. Among these, polyvinyl butyral is particularly preferable.

The content ratio of the alkali developer insoluble polymer is preferably 0.05 to 1.0 times by weight, more preferably 0.1 to 0.8 times by weight, with respect to the coloring component.
If the amount is less than 0.05 times the weight of the coloring component, the desired film thickness and optical density may not be achieved at the same time. On the other hand, if it exceeds 1.0 times by weight, development becomes difficult.

As the solvent used for the photosensitive paste, known general organic solvents can be used, and examples thereof include alcohol-based, ester-based, ketone-based and ether-based solvents. A preferable solvent can be appropriately selected depending on the method of applying the photosensitive composition or the photosensitive paste.

The light-shielding portion-forming photosensitive paste according to the present invention is prepared by adding a pigment dispersant or the like to the mixture of the above components, if necessary, and using a three-roll, ball mill, paint shaker, homogenizer or the like to prepare the pigment. It can be adjusted by performing dispersion.

The method for manufacturing a color filter according to the present invention will be described in detail below, but the present invention is not limited to this.

First, red is placed at a predetermined position on the center side of the transparent substrate.
A colored pattern portion having three-color pixels of green and blue and a light-shielding portion forming gap is formed by a known method such as a photolithography method, a photosensitive paste method, a printing method, an electrodeposition method, and a dyeing method.
The gap for forming the light shielding portion is usually formed between pixels.

Then, the photosensitive paste is coated on the entire surface of the transparent substrate having a predetermined coloring pattern by using a spinner, a roll coater, a die coater or the like, and then dried by a hot air oven or a hot plate. . Drying conditions are usually in the range of 80 to 100 ° C. and 5 to 10 minutes. At this time, it is preferable that the film thickness of the light-shielding portion after drying is made uniform with the film thickness of the pixel portion.

Subsequently, the entire surface is exposed from the back surface side of the transparent substrate with an ultrahigh pressure mercury lamp, a chemical lamp, a high pressure mercury lamp or the like.
At this time, the colored pattern acts as a kind of mask. That is, the photosensitive resin coating film on the pixels is not cured because light does not pass therethrough, and the photosensitive resin coating film in the gap portion between the pixels is photocured.

After the exposure is completed, a predetermined development is subsequently carried out.
By developing, the unexposed area on the pixel swells, and the cured product made of the resin coating film for forming the light shielding area in the gap between the pixels remains on the transparent substrate, and a predetermined light shielding area is formed between each pixel. It After development, a non-exposed portion is peeled and removed by performing a spray rinse with water or the like. The development can be carried out by spraying a developing solution, immersing in a developing solution, or applying ultrasonic waves while immersing in the developing solution. When it is immersed in the developing solution, it can be performed by immersing it for about 1 minute. As the developer, a developer containing an alkaline aqueous solution such as sodium carbonate, caustic soda, caustic potash, and ethanolamine as a main component can be preferably used.

In the present invention, since the alkali developing solution insoluble polymer is contained in the photosensitive paste for forming the light-shielding portion, the light-shielding portion is characterized by little change in film thickness and optical density before and after development. That is, by adjusting the film thickness of the photosensitive paste for forming the light-shielding portion after drying to be the same as the film thickness of the pixel portion, a color filter having good flatness can be obtained.

After completion of development and spray rinsing, post-baking is performed, and if necessary, top coat and IT
O film formation or the like can be performed.

Further, a frame light-shielding portion can be formed on the peripheral side of the colored pattern portion. When the light-shielding portion is not formed on the outside of the frame light-shielding portion, it is preferable to use a mask for frame processing to form the light-shielding portion. That is, it is possible to use a mask that transmits light only to the central colored pattern portion and the frame-forming portion having a predetermined width outside the central colored pattern portion and does not transmit light to a portion outside thereof.

[0034]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited thereto.

The flatness and the thickness of the coating film were measured with a stylus type surface meter, and the optical density was calculated from the transmittance of visible light.

Example 1 Polyamic acid solution of N-methylpyrrolidone (25 wt.
%) With a red, green, and blue organic pigment dispersed therein to prepare a colored paste. Each of these colored pastes was applied onto a glass substrate with a spinner, and a pattern was formed using an etching method using a positive resist. In this way, the film thickness is 1.5 μm at the center of the glass substrate.
A predetermined colored pattern portion including the red, green, and blue pixels and the light shielding portion gap was formed.

On the other hand, 5% by weight of an acrylic polymer obtained by copolymerizing acrylic acid with styrene and methyl methacrylate in an equal amount and 3% by weight of trimethylolpropane triacrylate,
6% by weight of carbon black, 5% by weight of polyvinyl butyral, 1% by weight of α-aminoacetophenone and 80% by weight of methyl cellosolve were added, and dispersed by beads mill to prepare a photosensitive paste for forming a light shielding part. This paste was applied over the entire surface of the substrate having the colored pattern formed thereon by a spinner, and dried at 80 ° C. for 5 minutes. The film thickness at this time was 1.5 μm.

Next, the glass surface side (back side) of the substrate was exposed with a chemical lamp at a light amount of 100 mJ / cm ² . At this time, in order to form a frame light-shielding portion on the peripheral portion of the colored pattern portion, exposure was performed using a mask that allows light to pass through only the colored pattern portion and a portion having a width of 5 mm outside thereof. The exposure hardened the photosensitive paste in the gaps between the pixels and the frame portion.

Then, immersion development was carried out for 1 minute using a 2% aqueous solution of sodium carbonate as a developing solution to remove the unexposed photosensitive paste on the pixels. At this time, since the photosensitive paste contained the alkaline developer insoluble polymer, the hardened portion was not dissolved by the development.

Subsequently, post baking was carried out at 200 ° C. for 1 hour to obtain a color filter. When the optical density and the film thickness before and after the development were measured in the frame light-shielding portion outside the colored pattern portion, as shown in Table 1, there was no change before and after the development, and the film thicknesses of the pixel and the light-shielding portion were uniform. The color filter had good flatness and sufficient light-shielding properties.

Comparative Example 1 A light-shielding portion was formed in the same manner as in Example 1, except that the photosensitive paste for light-shielding portion did not contain polyvinyl butyral.
The optical density and film thickness were measured before and after development. As a result, Table 1
As shown in (3), the film thickness was greatly reduced after development and became thinner than the pixel portion, and the optical density was significantly reduced as compared with that before development, resulting in a poor quality color filter having poor flatness and light-shielding properties.

[0042]

[Table 1]

[0043]

In the color filter according to the present invention, since the light-shielding portion contains the alkali developer insoluble polymer, the change in film thickness before and after the development of the light-shielding portion and the decrease in optical density are small. Therefore, since the film thickness of the light shielding part can be determined by the initial coating film thickness, the film thickness of the light shielding part can be made equal to the film thickness of the pixel part, and a color filter having extremely excellent flatness can be obtained. it can. Moreover, since the optical density of the light-shielding portion can be arbitrarily determined by the pigment density of the photosensitive paste, the target optical density can be easily achieved.

In the conventional light-shielding portion, the exposed portion is photo-cured and the unexposed portion is dissolved and removed during development. In the light-shielding portion of the color filter according to the present invention, the exposed portion is photo-cured. In addition, the unexposed portion is characterized in that it swells during development, and is therefore removed by peeling. Therefore, if only the interface with the transparent substrate is cured in the exposed portion, there is a difference in swelling from the unexposed portion even if not completely cured, and thus pattern formation can be performed by rinsing. That is, for exposure, it is sufficient that the light amount is such that the photosensitive paste layer and the transparent substrate are adhered to each other. Therefore, excellent exposure sensitivity can be obtained with an extremely small amount of light.

That is, according to the present invention, it is possible to obtain a color filter having a light-shielding portion that simultaneously satisfies all of the light-shielding property, the exposure sensitivity, and the flatness.

Claims (4)

[Claims] 1. A color filter having at least a transparent substrate and a colored pattern portion having pixels of a plurality of colors formed at a predetermined position on the center side of the transparent substrate and a light shielding portion formed between the pixels. A color filter, wherein the light-shielding portion is composed of a cured product of a photosensitive paste containing a coloring component, a photosensitive composition, an alkali developer insoluble polymer and a solvent as main components. 2. A method of manufacturing a color filter comprising the following steps (A) to (D): (A) A step of forming a colored pattern portion having a plurality of color pixels and a light-shielding portion forming gap at a predetermined position on the center side of the transparent substrate, and (B) a coloring component and a photosensitive composition on the transparent substrate. Of a photosensitive paste mainly composed of an object, an alkali developer insoluble polymer and a solvent, and drying, (C) exposing from the back side of the transparent substrate to cure the coating film in the light-shielding portion forming gap portion. Step (D) A step of developing and removing the coating film on the pixel. 3. The color filter according to claim 1, wherein the coloring component in the photosensitive paste is an organic pigment or an inorganic pigment, and the alkali developer insoluble polymer is a vinyl polymer. 4. The method for producing a color filter according to claim 2, wherein the coloring component in the photosensitive paste is an organic pigment or an inorganic pigment, and the alkali developer insoluble polymer is a vinyl polymer.