JP2002333630A - Color filter and color liquid crystal display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color liquid crystal display element having satisfactory display quality by suppressing interference fringes in a screen near to a frame part. SOLUTION: In a color filter having fixed spacers, the color filter for a liquid crystal display element is characterized in that the modulus of rigidity per 1 mm<2> square of the color filter screen of the spacer positioned in the sealing part is higher than that of the spacer positioned outside the display screen. The color liquid crystal display element is formed by using the color filter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color liquid crystal display device using a color filter having a fixed spacer.

[0002]

2. Description of the Related Art Conventionally, a color liquid crystal display element has a structure in which an electrode substrate having a thin film transistor (TFT) and a plurality of scanning electrodes and a substrate on a color filter side are maintained in order to maintain the thickness (cell gap) of a liquid crystal layer. In between, beads such as plastic or silica or glass fibers are used as spacers. Here, since the bead spacers and the like are scattered, it is not fixed at which position (in-plane position) between the electrode substrate and the substrate on the color filter side.
JP-A-56-140324, JP-A-63-32405,
JP-A-4-93954, JP-A-5-196946, and JP-A-10-82909 propose a liquid crystal display device using a spacer formed on a colored layer of a color filter or a spacer formed by overlapping colored layers. I have.

[0003]

In a color liquid crystal display device using plastic beads or the like as a spacer, the position of the spacer is not fixed because the spacer is scattered. I do it. When the spacer is located on the display pixel portion, light is scattered or transmitted, and there is a problem that the display quality of the liquid crystal display element is reduced. In addition, there is also a problem that the cell gap becomes non-uniform due to the aggregation of the spacers. Further, the spacer may move during voltage application or during transportation of the liquid crystal display element, and may damage the alignment film.

[0004] As described above, in the bead spacer, it is necessary to perform a process of uniformly dispersing the spacer, or it is necessary to control the particle size distribution of the spacer with high accuracy. Was difficult to get. Furthermore, since the thickness of the pixel portion and the frame portion in the color filter are different, and the density of the spacers applied to the frame portion tends to be lower than that of the pixel portion,
Reflecting the non-uniformity of the cell gap determined in such a state, problems such as generation of interference fringes on a screen close to the frame were likely to occur.

For this reason, a color filter having a spacer having a fixed formation position is disclosed in Japanese Patent Application Laid-Open No. 56-14032.
4, JP-A-63-32405, JP-A-4-93954,
It is proposed in Japanese Patent Application Laid-Open Nos. 5-196946 and 10-82909. However, although there is disclosure of the shape and characteristics of the spacer alone, the display screen, the seal portion, and a liquid crystal display element having a high display quality without interference fringes can be obtained by arranging spacers outside the display screen with any characteristics. There is no disclosure of what can be done. In the liquid crystal display device using a color filter having a fixed spacer, sealing portion, if not the proper relationship of rigidity per the color filter screen 1 mm ² corners of the spacer outside the display screen, the interference fringes on the screen close to the frame portion Problems such as the occurrence of problems still remain.

In view of the above problems, the present invention provides a color filter and a color liquid crystal display device which realize a sufficient cell gap, maintain a uniform cell gap over the entire display screen, and overcome the above-mentioned conventional disadvantages. The task is to provide.

[0007]

In order to achieve the above object, a color filter and a color liquid crystal display device of the present invention have the following arrangement. That is, "in the color filter having a fixed spacer, and wherein the said color filter screen 1mm shear modulus per ^second corner of the seal portion the spacer is greater than the shear modulus per ^second corner said color filter screen 1mm of the display screen outside the spacer Color filter or color liquid crystal display device for liquid crystal display device. The present invention will be described in detail below.

[0008]

Embodiments of the present invention will be described below. FIG. 1 shows an example of a color liquid crystal display device of the present invention.
However, the present invention is not limited to this.

The color filter used in the liquid crystal display device of the present invention is provided with a black matrix as required on a substrate, and a colored layer (R, R,
G, B), and a protective film and a transparent electrode are laminated as necessary. The formation of the color filter is not limited to the transparent substrate side such as a glass or a polymer film, but can also be performed on the driving element side substrate. The pattern shape of the color filter includes a stripe shape and an island shape, but is not particularly limited.

The method of forming the pixel includes, but is not particularly limited to, a photolithography method, a printing method, and an electrodeposition method. In consideration of the pattern formability and the like, it is more preferable to use the photolithography method. In a color filter that requires a black matrix, the black matrix is a resin black matrix composed of a resin and a light shielding material, a black matrix composed of a metal having a light shielding property,
Any of a black matrix composed of two or three colored layers of colored layers may be used. There is also no particular limitation on the resin that is a component of the black matrix and the pixel, regardless of whether it is photosensitive or non-photosensitive, such as acrylic resin, alkyd resin, melamine resin, polyvinyl alcohol, phenol resin, polyamide, polyamide imide, and polyimide. Resin can be used. Particularly, a resin soluble in an aqueous alkali solution is desirable because the equipment can be simplified in the developing or etching step. Among resins soluble in an aqueous alkali solution, a resin having a carboxyl group is preferably used, and specifically, an acrylic resin and a polyimide resin are preferable in terms of solvent resistance. In the case of a polyimide resin, precursors of the polyimide resin are particularly preferable because they function as a dispersant for the pigment. Further, from the viewpoint of heat resistance of the color filter, it is preferable to use a polyimide resin. As the coloring material used in the present invention, general coloring agents can be used regardless of organic pigments, inorganic pigments, and dyes.

Not all spacers need to be fixed spacers, and only beads or glass fiber spacers of conventional plastics or silica may be sprayed on a part of them, or both the spacers to be sprayed and the fixed spacers may be used simultaneously. Or a fixed spacer only. Outside the display screen, it is more preferable to use a fixed spacer in consideration of movement and the like. The formation of the fixed spacer
The colored layers of R, G, and B may be formed by overlapping each other, or only the spacer may be formed on the colored layer or black after forming the colored layer, after forming the protective film, or after forming the transparent electrode. It may be formed separately on a matrix or the like. When it is formed on a colored layer, it is more preferable to use a transparent material so as not to affect the colored layer. The shape of the spacer need not be a columnar body, and may be a dome-shaped body, a spherical body, or another shape as long as it has an adhesive surface to the color filter. Also, the cross-sectional shape of the surface that contacts the drive element side substrate is
The shape may be any of a square, a rectangle, and a circle. Regarding the formation position of the fixed spacer, it may be formed inside the display screen, in the seal portion, or outside the display screen. As long as there is no problem in the rigidity per 1 mm ^{2 of} the color filter screen, the spacers may be arranged for each specific colored layer or may be arranged at a fixed pitch. The number of color filter screen 1mm per ^second angle of fixed spacers, at a site located is uniform fixed spacer, around a certain one fixed spacer, fixed spacer is arranged per ² square color filter screen 1mm Indicates the number of Density of the color filter screen 1mm per ^second corner of the spacer to be sprayed is sprayed area am
If m ² and the number of sprays are b, b / a (pieces / mm ² ) is obtained. Here, the rigidity and the rigidity per 1 mm ² square of the color filter screen will be described. Rigidity (kg / μ
m) indicates the load required to displace one spacer by 1 μm. The rigidity per 1 mm ² square of the color filter screen is represented by n: the number of spacers existing in 1 mm ² square of the color filter screen, and m: the rigidity of one spacer.
(Kg / μm), it is represented by m × n.

An example of the method for producing a color filter of the present invention will be described.

The method for producing a color filter according to the present invention comprises applying a color paste comprising at least a polyimide precursor, an organic pigment, and a solvent on a transparent substrate, followed by air drying.
A polyimide precursor colored film is formed by heat drying, vacuum drying, or the like. In the case of heating and drying, use an oven, a hot plate, etc., in the range of 50 to 180 ° C. for 1 minute to 3 minutes.
It is preferable to carry out for a time. Next, a pattern is formed on the thus obtained polyimide precursor colored film by ordinary wet etching. First, a positive photoresist is applied on the polyimide precursor colored film to form a photoresist film. Subsequently, a mask is placed on the photoresist film, and ultraviolet light is irradiated using an exposure device. After the exposure, the photoresist coating and the polyimide precursor colored coating are simultaneously etched with an alkaline developer for a positive photoresist. After etching, the photoresist is stripped off film which has become unnecessary.

The polyimide precursor colored film is then converted into a polyimide colored film by heat treatment. The heat treatment is usually performed at 150 to 450 ° C., preferably at 18 ° C. in air, in a nitrogen atmosphere, or in vacuum.
It is performed continuously or stepwise at a temperature of 0 to 350 ° C. for 0.5 to 5 hours. When the above steps are performed for three color pastes such as red, green, and blue, and if necessary, a black color paste, a color filter for a liquid crystal display device can be manufactured.

Next, a liquid crystal display device produced using this color filter will be described. A transparent protective film is formed on the color filter as needed, and a transparent electrode such as an ITO film is formed thereon. It should be noted that the color filter of the present invention is set in the IPS mode (In Plane).
When applied to (Switching), a transparent electrode film is not required. The spacer is formed after forming the colored layer, after forming the protective film, or after forming the transparent electrode.

Next, a liquid crystal alignment film subjected to a rubbing treatment for liquid crystal alignment is provided on the color filter substrate and the driving element side substrate. These substrates are attached to each other with a spacer interposed therebetween. In addition, on the driving element side substrate, a projection for light diffusion, a thin film transistor (TFT)
Devices, thin film diode (TFD) devices, and scanning lines,
By providing signal lines and the like, a TFT liquid crystal display device or a TFD liquid crystal display device can be manufactured. Next, after injecting liquid crystal from an injection port provided in the seal portion, the injection port is sealed. Furthermore, a module is completed by mounting a polarizing plate, a phase difference plate, an IC driver, and the like.

According to the liquid crystal display device of the present invention, no interference fringes occur on the screen near the frame portion, so that a liquid crystal display device with high display quality can be obtained. This is probably the seal <
Outside the display screen, the spacer becomes softer from the outside of the display screen toward the seal part, so stress concentrates on the frame part, which is the boundary between the seal part and the display screen, and the cell gap becomes particularly narrow, causing interference fringes. On the other hand, it is presumed that if the area outside the display screen is smaller than the seal area, no interference fringes are generated because there is no concentration of stress on the frame.

[0018]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto. Example 1 (Preparation of color filter) 4,4'-diaminodiphenyl ether and bis (3- (Aminopropyl) tetramethyldisiloxane was charged together with γ-butyrolactone and N-methyl-2-pyrrolidone to prepare 3,3 ′, 4,4′-.
After adding and reacting biphenyltetracarboxylic dianhydride, phthalic anhydride was added and reacted to obtain a polyamic acid solution. Carbon black (MA100, manufactured by Mitsubishi Chemical Corporation) was mixed and dispersed in the polyamic acid solution to prepare a black paste. A black paste was applied on an alkali-free glass (Corning Corp., 1737) substrate, and photolithographically processed to a film thickness of 1.2 μm. next,
The red, green, and blue pigments were mixed and dispersed in a polyamic acid solution to obtain red, green, and blue colored pastes. Each of the colored pastes was subjected to photolithographic processing in the form of a stripe in order, to have an area of 100 × 300 μm and a film thickness of 1.9 μm. A transparent protective film (Optomer 6917, manufactured by JSR Corporation) was formed with a film thickness of 1.2 μm to prepare a color filter.

(Formation of Fixed Spacer) An acrylic negative photosensitive material (manufactured by JSR Corporation) on a color filter
(Optomer NN700) was applied by a spinner, and then pre-baked on a hot plate at 80 ° C. for 3 minutes. Thereafter, exposure was performed at 500 mJ / cm ² (h-ray) through a mask using an exposure machine PLA-501F manufactured by Canon Inc. After exposure, it is immersed for 90 seconds in a developing solution composed of a 0.14% aqueous solution of tetramethylammonium hydroxide,
Development was performed. Further, post-baking was performed in an oven at 220 ° C. for 60 minutes to form a spacer. The spacers were formed on the red pixels inside the display screen and at a pitch of 1 mm outside the display screen. Spacer is 300μ in the display screen
One per m square, and one per 1 mm square outside the display screen. The upper area of the spacer in the display screen is about 110
μm ² and height was 5.0 μm. The upper area of the spacer outside the display screen was about 3500 μm ² , and the height was 5.0 μm.

(Measurement of rigidity) The spacers inside and outside the display screen were compressed, and the rigidity was measured. To measure, Inc.
DUH-20, a dynamic ultra-fine hardness tester manufactured by Shimadzu Corporation
1 was used. The rigidity of the spacer in the display screen is 0.
004 kg / μm, and the rigidity of the spacer outside the display screen was 0.13 kg / μm. The rigidity of the glass fiber spacer having a diameter of 6.9 μm (a micro rod manufactured by NEC Corporation) used for the sealing portion is 0.006 k.
g / μm.

(Preparation of Liquid Crystal Display Element) A glass fiber spacer was mixed with a sealant so as to have a density of 45 pieces / mm ^{2 in} the seal portion, and screen printing was performed.

[0022] The rigidity rate per ^second corner the color filter screen 1mm of the spacer in the display screen, per ² square screen 1mm spacer because 11 there, the spacer one of the rigidity of 0.004kg / μm × 11 pieces in 0.044kg
/ Μm. Outside the display screen, since there is one spacer per 1 mm ² of the screen, it is 0.13 kg / μm. In the seal portion, there are 45 spacers per 1 mm ² square of the screen, so the rigidity of one spacer is 0.006.
It is 0.27 kg / μm for 45 kg / μm. In other words, the rigidity per 1 mm ^{2 of} the screen is as follows: outside the display screen <seal portion. A color filter substrate and a transparent electrode substrate provided with a thin film transistor element were bonded. After the liquid crystal was injected from the injection port, the injection port was sealed to produce a liquid crystal display device. The manufactured liquid crystal display device was observed under a sodium lamp. No interference fringes were observed on the display screen.

Example 2 In Example 1, only the area of the spacer outside the display screen was changed to 2500 μm ² to produce a liquid crystal display device. As a result of measuring the rigidity of the spacer outside the display screen, 0.09
kg / μm. The rigidity per square of the color filter screen 1 mm ² of the spacer outside the display screen is
Since the per mm ² square spacer is one, 0.09
kg / μm. In other words, the rigidity per 1 mm ^{2 of} the screen is such that the seal portion <the outside of the display screen. The manufactured liquid crystal display device was observed under a sodium lamp. No interference fringes were observed on the display screen.

Comparative Example 1 A liquid crystal display device was produced in the same manner as in Example 1 except that only the density of the spacers in the seal portion was changed to 15 pieces / mm ² . 1 mm ^{2 of the} color filter screen of the spacer at the seal part
Rigidity rate per corner, because the per ² square screen 1mm spacer is 15, the spacer one of the modulus of rigidity 0.00
It becomes 0.09 kg / μm when 6 kg / μm × 15 pieces. In other words, the rigidity per 1 mm ^{2 of} the screen is such that the seal portion <the outside of the display screen.

The manufactured liquid crystal display device was observed under a sodium lamp. There were three interference fringes on the screen near the frame.

[0026] As in Examples 1 and 2, when the sealing portion and the display screen outside of said color filter screen 1mm screen outside the shear modulus per ^second corner spacer <seal portion, the interference fringes on the screen close to the frame portion Thus, a liquid crystal display element having high display quality and free from occurrence was obtained.

[0027]

The liquid crystal display device of the present invention has the following remarkable effects. (1) By defining the rigidity of the seal portion and the spacer outside the display screen per 1 mm ^{2 of the} color filter screen, interference fringes on the screen close to the frame of the liquid crystal display element are suppressed.
A liquid crystal display element with high display quality can be provided. (2) Since the spacers can be regularly formed and fixed, display quality is not impaired by the movement of the spacers.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a color liquid crystal display device using a color filter obtained according to the present invention.

[Explanation of symbols]

 1, 14: bright substrate 2: black matrix 3, 4, 5: colored layer 6: protective film 7: transparent electrode 8a: display spacer 8b: spacer outside display screen 8c: seal spacer 9,10: alignment film 11: Pixel electrode 12: Insulating film 13: Electrode attached to liquid crystal drive circuit 15: Spacer 16: Sealant 17: Liquid crystal

Claims (2)

[Claims] 1. In a color filter having a fixed spacer, the rigidity of the seal portion spacer per 1 mm ^{2 of the} color filter screen is larger than the rigidity of the spacer outside the display screen per 1 mm ^{2 of the} color filter screen. Characteristic color filters for liquid crystal display devices. 2. A color liquid crystal display device using the color filter according to claim 1.