JP3134549B2 - Color filter and method of manufacturing the same - Google Patents

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 As a color filter for a color liquid crystal display device, a method of manufacturing by a dyeing method, a printing method, a photolithographic method, an electrodeposition method, and the like has been put into practical use. Have 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, light leakage in a portion where no voltage is applied between the transparent electrodes, that is, a portion that does not contribute to display can be prevented, and color contrast can be increased. Further, in the case of the active matrix system, there is also an effect of preventing a malfunction due to light of the switching element.

Conventionally, various methods for forming the light-shielding portion have been proposed. The first is a method in which a chromium vapor deposition film or a sputtering film is formed on a glass substrate and patterned by etching. In this case, it is essential to produce a chromium film uniformly and without defects such as pinholes, and for patterning, multiple processes such as resist coating, exposure, development, baking, etching, and resist peeling are required. .

[0004] The second method is a method of applying an ink or paste colored with a black pigment using a printing machine, a spinner, a roll coater, or the like, and performing patterning by mask exposure. However, sufficient light shielding properties, dimensional accuracy, and flatness are required. It is difficult to realize.

[0005] Compared to these conventional methods, the backside exposure method is considered to be superior in dimensional accuracy and flatness, and is therefore promising (for example, JP-A-1-138530 and JP-A-3-209203). JP-A-3-284704
Issue publication). In other words, the backside exposure method is to form pixels on a transparent substrate in advance, apply a negative-type photosensitive coloring paste in which a light-shielding pigment is dispersed, and then apply each pixel as a mask to the transparent substrate side. This is a method of forming a light shielding portion in a gap between pixels by exposing from the (back side). At this time, since a frame light-shielding portion (light-shielding frame) is formed adjacent to the outside of the colored pattern portion including the pixels and the light-shielding portion, a frame processing mask can be used. The frame processing mask is a mask that transmits light only to a central portion, that is, a mask that transmits light only to a 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 characteristics such as light-shielding property, exposure sensitivity, and flatness by such a method has not been obtained. That is, in order to provide sufficient light-shielding properties, it is necessary to increase the thickness of the coating film or increase the amount of the coloring component in the paste. A light-shielding portion cannot be formed. That is, even if the exposure is performed for a long time, the film thickness is insufficient, the surface irregularities are severe, and the flatness is poor. Similarly, even if you try to increase the light-shielding properties, since the ultraviolet rays are attenuated by the coloring components,
There was a limit in light-shielding properties.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and has as its object to simultaneously satisfy all requirements for light-shielding properties, exposure sensitivity, and flatness independently of each other. A color filter having a light shielding portion and a method for manufacturing the same.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
This is achieved by 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 center side of the transparent substrate and a light shielding portion formed between the pixels. 3. The color filter according to claim 1, wherein the light-shielding portion comprises a coloring component, a photosensitive composition soluble in an alkali developer, a polymer insoluble in an alkali developer, and a cured product of a photosensitive paste containing a solvent as a main component.

(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 pixels of a plurality of colors and a gap for forming a light shielding portion at a predetermined position on the center of the transparent substrate; (B) forming a colored component on the transparent substrate; A step of applying and drying a photosensitive composition soluble in an alkali developing solution, a photosensitive paste containing an alkali developing solution-insoluble polymer and a solvent as main components, and (C) exposing from the back side of the transparent substrate to form a light-shielding portion. Curing the coating film in the gap portion for forming; (D) forming an alkaline developing solution on the coating film on the pixel;
Swelling and removing.

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

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

Hereinafter, the present invention will be described in detail.

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

The color filter of 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 of the transparent substrate. The color of each pixel is usually
Red, blue, and green, and the shape of each pixel is not particularly limited, but is generally a stripe shape, a mosaic shape, or the like. In addition, there is usually 10 pixels between each pixel.
A space of about 20 μm is provided, and a light shielding portion is formed in this space.

In the present invention, the photosensitive paste used for forming the light-shielding portion is soluble in a coloring component and an alkali developing solution.
The main components are a photosensitive composition, an insoluble polymer in an alkaline developer and a solvent.

The coloring components used in the photosensitive paste include organic pigments of carbon black, phthalocyanine, azilake, condensed azo, quinacridone, anthraquinone, perinone, perylene, ultramarine, navy blue and cobalt blue. And the like inorganic pigments. 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
The content is preferably from 30 to 30% by weight, more preferably from 3 to 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 becomes poor, and it becomes difficult to form a uniform coating film on the glass substrate.

Alkaline development used for photosensitive paste
As the photosensitive composition soluble in the liquid, one that can be cured by exposure to ultraviolet light and removed from unexposed portions by development to form a pattern image is used .
Examples of such a photosensitive composition soluble in an alkali developer include a resin having a photosensitive group such as cinnamic acid, or an acid group such as a carboxyl group in cellulose, acrylic, vinyl, or urethane. Resin, monomers or oligomers having an ethylenically unsaturated group, and those containing a photoinitiator as a main component can be used. Among these, a resin containing acrylic acid as an acrylic copolymer component, or a part of acrylic acid in the acrylic copolymer component, becomes an ethylenically unsaturated group by introducing a glycidyl group. Resin, such as
Mixtures containing a polyfunctional monomer such as trimethylolpropane trimethacrylate, and a functional oligomer such as an epoxy diacrylate, and a photoinitiator such as "Irgacure" 907 and "Irgacure" 369 (manufactured by Ciba-Geigy). it can.

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

The insoluble polymer in the alkali developing solution used in the photosensitive paste has a property that it is insoluble in a developing solution composed of an aqueous solution of sodium carbonate, caustic soda, caustic potash, ethanolamine and the like, and has an affinity for a coloring component. Non-sensitive polymers are preferred. Examples of such an alkali developer insoluble polymer include vinyl polymers such as polyvinyl acetate, polyvinyl alcohol and polyvinyl butyral, and various modified products thereof. Among them, polyvinyl butyral is particularly preferable.

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

As the solvent used for the photosensitive paste, known general organic solvents can be used, and examples thereof include alcohols, esters, ketones and ethers. A suitable solvent can be appropriately selected depending on a method of applying a photosensitive composition or a photosensitive paste soluble in an alkali developer .

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

Hereinafter, the method for producing a color filter according to the present invention will be described in detail, but the present invention is not limited thereto.

First, at a predetermined position on the center side of the transparent substrate, red,
A colored pattern portion having three color pixels of green and blue and a gap for forming a light shielding portion 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 the pixels.

Next, the above-mentioned photosensitive paste is applied to the entire surface of the transparent substrate on which a predetermined colored pattern is formed using a spinner, a roll coater, a die coater or the like, and then dried in a hot-air oven or a hot plate. . Drying conditions are usually in the range of 80 to 100 ° C. for 5 to 10 minutes. At this time, it is preferable to make the thickness of the light-shielding portion after drying equal to the thickness of the pixel portion.

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

After the exposure, predetermined development is performed.
By performing the development, the unexposed portions on the pixels swell, and the cured product formed of the resin coating film for forming the light shielding portion in the gap between the pixels remains on the transparent substrate, and a predetermined light shielding portion is formed between the pixels. You. After the development, unexposed portions are removed by spray rinsing with water or the like. The development can be carried out by spraying the developer, immersing in the developer, or applying ultrasonic waves while immersing in the developer. When immersed in a developer, it can be carried out by immersion for about 1 minute. As the developing solution, those mainly containing an aqueous alkali solution such as sodium carbonate, caustic soda, caustic potash, and ethanolamine can be preferably used.

In the present invention, since the photosensitive paste for forming the light-shielding portion contains an alkali developer-insoluble polymer, the light-shielding portion is characterized in that the change in film thickness and the change in optical density before and after development are small. That is, a color filter with good flatness can be obtained by making the thickness of the photosensitive paste for forming a light-shielding portion after drying equal to the thickness of the pixel portion.

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

Further, a frame light-shielding portion can be formed on the periphery of the colored pattern portion. In the case where no light-shielding portion is formed outside the frame light-shielding portion, it is preferable that the light-shielding portion is formed using a frame processing mask. That is, it is possible to use a mask that transmits light only to the central colored pattern portion and a frame forming portion having a predetermined width outside the central colored pattern portion, and does not transmit light to portions outside the central colored pattern portion.

[0034]

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

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

Example 1 A solution of polyamic acid in N-methylpyrrolidone (25 wt.
%) To prepare colored pastes in which red, green, and blue organic pigments are dispersed. Each of these colored pastes was applied on a glass substrate by a spinner, and a pattern was formed by an etching method using a positive resist. In this way, the film thickness is 1.5 μm each at the center on the glass substrate.
A predetermined colored pattern portion composed of red, green, and blue pixels and a light-shielding portion gap was formed.

On the other hand, 5% by weight of an acrylic polymer obtained by copolymerizing acrylic acid, styrene and methyl methacrylate in the same amount, and 3% by weight of trimethylolpropane triacrylate,
Carbon black (6% by weight), polyvinyl butyral (5% by weight), α-aminoacetophenone (1% by weight) and methyl cellosolve (80% by weight) were added, and the mixture was dispersed in a bead mill to prepare a light-shielding portion-forming photosensitive paste. This paste was applied to the entire surface of the substrate on which the colored pattern was formed, using a spinner, and dried at 80 ° C. for 5 minutes. The film thickness at this time was 1.5 μm.

Next, the substrate was exposed from the glass surface side (back side) 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 at the periphery of the colored pattern portion, exposure was performed using a mask that allows light to pass only through the colored pattern portion and a portion having a width of 5 mm outside the colored pattern portion. Exposure hardened the photosensitive paste in the gaps between pixels and in the frame.

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

Subsequently, post baking was performed 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 at 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 thickness 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 the light-shielding portion did not contain polyvinyl butyral.
The optical density and film thickness before and after development were measured. As a result, Table 1
As shown in (1), the film thickness was greatly reduced after the development and became thinner than the pixel portion, and the optical density was also significantly reduced as compared with that before the development, resulting in a poor quality color filter having poor flatness and light shielding properties.

[0042]

[Table 1]

[0043]

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

In the conventional light-shielding portion, the exposed portion is light-cured and the unexposed portion is dissolved and removed at the time of development. However, the light-shielding portion of the color filter according to the present invention has a light-cured exposed portion. In addition, the unexposed portions have the characteristic of swelling during development, and thus are removed and removed. Therefore, if even the interface with the transparent substrate is hardened in the exposed portion, even if it is not completely hardened, there is a difference in swelling from the unexposed portion, so that the pattern can be formed by rinsing. That is, in the exposure, an amount of light sufficient for bonding the photosensitive paste layer and the transparent substrate is sufficient, so that 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 properties, exposure sensitivity, and flatness independently of each other.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-297502 (JP, A) JP-A-3-15025 (JP, A) JP-A-2-287303 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G02B 5/20 101 G02F 1/1335 505

Claims (4)

(57) [Claims] 1. A color filter having at least a transparent substrate and a colored pattern portion having a plurality of color pixels formed at predetermined positions on the center side of the transparent substrate and a light shielding portion formed between the pixels. , the light shield unit is coloring components, A
What is claimed is: 1. A color filter comprising a photosensitive composition soluble in a alkaline developer, an insoluble polymer in an alkaline developer, and a cured product of a photosensitive paste containing a solvent as a main component. 2. A method for manufacturing a color filter, comprising the following steps (A) to (D). (A) a step of forming a colored pattern portion having pixels of a plurality of colors and a gap for forming a light shielding portion at a predetermined position on the center side of the transparent substrate; and (B) forming a colored component, an alkali on the transparent substrate.
A photosensitive composition soluble in the developer, an alkaline developer insoluble polymer and a photosensitive paste containing a solvent as a main component are applied,
A step of drying, (C) a step of exposing from the back side of the transparent substrate and curing the coating film in the gap portion for forming the light shielding portion;
(D) swelling of the coating film on the pixel by the action of an alkali developing solution;
A step of moisturizing and removing. 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 polymer insoluble in the alkali developing solution 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.