JPH10282327A - Color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of display quality due to scattering of a spacer by providing a columnar material on a non-display part to hold liquid crystal holding spaces with the layer of coloring picture elements and forming a protecting film of non-conductive inorganic compound. SOLUTION: A black matrix 2 is formed on a transparent substrate 1 including a glass substrate by using a desired pattern and red, green and blue coloring picture elements 3 are formed thereon. For example, the red coloring picture element 3R is first formed (A). Then, the green coloring picture element 3G is formed and, when the coloring picture element is formed, a green columnar material 4G is formed on the columnar material formation area with the same material as the coloring picture element at the same time when the coloring picture element is formed (B). Similarly, the blue coloring picture element 3B and a blue columnar material 4B are formed (C). A non-conductive inorganic compound thin film 5 is formed on the coloring picture element and the columnar material. The movement of a spacer, when voltage is applied or during carriage, is prohibited and damage to an orientation film and a TFT is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color filter, and more particularly to a color filter which has means for maintaining a distance between substrates for holding liquid crystal, which is suitable for a color liquid crystal display device, and which has excellent performance without deterioration of liquid crystal for a long time. Regarding filters.

[0002]

2. Description of the Related Art A liquid crystal display device is formed by opposing a transparent substrate such as glass provided with a transparent electrode with a liquid crystal layer interposed therebetween, and orienting the liquid crystal in a certain direction by a voltage applied between the electrodes. The image is displayed using transparent and opaque parts. A color liquid crystal display device generally includes three colored pixels of red (R), green (G), and blue (B) on any one of transparent electrode substrates, and three primary colors are formed by a shutter action of liquid crystal. A desired color is displayed by adding colors. In general, a spacer is provided between two substrates facing each other in order to maintain a space between them, so that the thickness of the liquid crystal layer is kept uniform.

However, the spacer is a foreign substance for the liquid crystal material, and the liquid crystal molecules whose alignment is to be regulated by the alignment film are regulated by the spacer, so that the alignment abnormality occurs near the interface between the spacer and the liquid crystal molecule. This raises a problem that the liquid crystal molecules around the spacer cannot be controlled in orientation depending on the ON / OFF state of the voltage of the electrode for driving the liquid crystal, and display is not performed normally.

The spacers are dispersed in liquid crystal by assembling a liquid crystal display device after spraying glass fibers and spherical synthetic resin particles on one of the substrates. The spacer may move by the application. Then, the movement of the spacer causes damage to the alignment film, damage to the electrode for driving the liquid crystal and the TFT, or causes a problem that the display quality is deteriorated due to the uneven spacing between the two substrates. . As described above, although the purpose of the spacer is to maintain the thickness of the liquid crystal layer uniformly, the use of the spacer has a problem that the display quality is deteriorated.

Therefore, in a color filter, three colored layers of red (R), green (G), and blue (B) are superimposed to maintain a liquid crystal sandwiching distance, and a conventional spacer is not used. One is proposed in JP-A-5-196946. Further, the publication also proposes that a colored layer is preferentially overlapped with a black matrix portion, which is a non-display portion, to form a spacer. Thereby, although the adverse effect due to the abnormal alignment and the movement of the spacer caused when the spacer is dispersed in the liquid crystal is improved, the colored layer forming composition forming the color filter has a bad influence on the liquid crystal in the pigment, the dye and the like. In addition, there is a problem that the liquid crystal gradually contaminates the liquid crystal, causes display defects, and significantly reduces the durability of the liquid crystal display device.

For this reason, a transparent protective film is formed on a colored pixel of a color filter in order to prevent a substance which adversely affects the liquid crystal from being dissolved from the colored layer forming composition. There is a demand for a protective film having excellent characteristics with a small amount of elution into the protective layer.

In particular, in-plane switching (IP
In a liquid crystal display device using a display method (transverse electric field method) in which a liquid crystal is driven on a plane parallel to a display surface called an S) mode, an electrode is provided only on a driving substrate side such as a TFT.
Since it is not necessary to provide an electrode for driving a liquid crystal from an ITO film or the like on the color filter, the possibility of degradation of the liquid crystal due to elution of the degradation component of the liquid crystal from the colored pixels is greater than that provided with an ITO film. It is required to form a protective film having better characteristics.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color filter which prevents the display quality of a liquid crystal display from deteriorating due to the dispersion of spacers in the liquid crystal display and which does not deteriorate the liquid crystal for a long period of time. It is an issue. Another object is to provide a color filter optimal for a liquid crystal display device using an IPS mode.

[0009]

According to the present invention, in a color filter, a non-display portion has a columnar body for maintaining a liquid crystal sandwiching interval by lamination of colored pixels and a protective film made of a non-conductive inorganic compound. It is a color filter. Further, in the color filter, a non-display portion has a columnar body that holds a liquid crystal sandwiching interval by a transparent photosensitive material, and a portion other than the columnar body has a protective film made of the transparent photosensitive material. It is a color filter. Further, in the above color filter, the inorganic compound is at least one selected from silicon nitride, silicon oxide, and metal composite oxide.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A color filter according to the present invention will be described with reference to the drawings. FIG. 1 is a view for explaining one embodiment of the present invention, and is a view showing a partial cross section of a color filter. The color filter is formed by depositing chromium metal, chromium oxide, chromium oxynitride, or the like on a transparent substrate 1 such as a glass substrate by sputtering or the like, or a synthetic resin composition in which carbon black, metal oxide, or the like is dispersed. After the application, the black matrix 2 is formed using a desired pattern, and then the red, green, and blue colored pixels 3 are formed.
Is formed. In particular, in the IPS mode, a black matrix using a synthetic resin composition having improved resistance is preferable.

The colored pixels can be formed by applying a synthetic resin composition containing a pigment or the like and removing unnecessary portions using a predetermined pattern. If you use a conductive material,
Without forming a resist pattern on the coating film of the synthetic resin composition, directly on the coating film of a photosensitive material containing a pigment or the like, a colored pixel is formed only by a development process after exposure using a predetermined photomask. Can be formed.

The colored pixels may be formed in the same thickness for each of red, green, and blue. However, in order to prevent the liquid crystal from being colored when no voltage is applied due to a difference in the wavelength of light, the colored pixels are formed on the liquid crystal layer. In order to change the thickness, the thickness of each colored pixel may be changed. When the thickness of the colored pixels is increased in the order of red, green, and blue, it is preferable that the colored pixels be formed in order of decreasing thickness in the order of red, green, and blue. FIG. 1 (A)
Shows an example in which the red colored pixel 3R is formed first.

Next, as shown in FIG. 1B, a green colored pixel 3G is formed. Then, at the time of forming the colored pixel, using a photomask having a pattern for forming the columnar body, a green columnar body 4G is formed on the columnar body forming portion with the same material as the colored pixel at the same time as the formation of the colored pixel. Form.
The columnar body may be formed on a red colored pixel as shown in FIG. 1B, or may be formed on a region where no colored pixel is formed.

Next, as shown in FIG. 1C, similarly, a blue colored pixel 3B and a blue columnar body 4B are formed.

Adjustment of the height of the columnar body by lamination of the colored layers can be performed by adjusting the amount of the colored layers flowing out to the periphery. That is, when the thickness of the coloring layer to be formed is large, the area of the coloring layer for the columnar body formed earlier is large, because the flow-out amount of the synthetic resin composition due to the difference in height from the surroundings is small. In the case where the thickness of the colored layer to be formed is large, and conversely, if the area of the previously formed colored layer is small, the applied colored layer flows out to the surroundings and the height is leveled, and the formed colored layer is formed. This is because the height of the object becomes low. By utilizing such a phenomenon,
While making the thickness of the colored pixel of the display unit a predetermined thickness,
It is possible to adjust the height of the columnar body on which the coloring layers are laminated to the same liquid crystal sandwiching interval.

For example, if one pillar is provided for each colored pixel having a length of 0.3 mm and a width of 0.1 mm, 1 column is provided.
About 33 spacers can be formed in mm ² . This number is smaller than a value of 100 to 200 / mm ^2, which is a number when a spacer such as a spherical shape of a synthetic resin is mixed with a normal liquid crystal, but the dispersion or deviation of the particle size distribution of the spacer using the synthetic resin is small. Since the display is free from abnormalities and is uniformly arranged over the entire display surface, the load can be evenly distributed, so that the object can be sufficiently achieved.

Next, as shown in FIG. 1D, silicon nitride, silicon oxide, tantalum oxide, aluminum oxide, metal composite oxide,
A thin film 5 of at least one non-conductive inorganic compound selected from other metal oxides is formed. Specifically, S
_{iO x, SiN x, Al 2} O 3, TiO 2 and the like.
These films can be formed by a film formation method such as a sputtering method, a CVD method, or a plasma CVD method.
In particular, a silicon nitride thin film having excellent properties as a protective film can be formed at a relatively low temperature of 200 to 300 ° C. using silane, ammonia, or the like as a raw material by using a plasma CVD method. is there. The protective film of these non-conductive inorganic compounds has a thickness of 0.05 to 1.0 μm.
m. More preferably,
0.1 to 0.5 μm, more preferably 0.2 to 0.5 μm.
It is about μm. If the thickness is less than 0.05 μm, sufficient protection performance cannot be obtained, and if the thickness is more than 1.0 μm, cracks and the like are likely to occur due to stress and the like, which is not preferable. Further, the color filter of the present invention,
After forming the non-conductive inorganic compound protective film, a conductive film such as an ITO film for driving liquid crystal may be formed.

[0018]

Embodiments of the present invention will be described below in more detail. Example 1 7 having a short side of 370 mm, a long side of 470 mm, and a plate thickness of 1.1 mm
A 0.2 μm-thick chromium oxide / chromium laminated structure film was formed on 059 glass (manufactured by Corning Incorporated) by sputtering. Observation from the glass surface side gave a low reflection optical density of 4.0. Next, a resist (OFPR-800, manufactured by Tokyo Ohka) is applied to a thickness of 0.6 μm, exposed by using a mask having a pre-baked and predetermined pattern, and after developing the resist, the chromium oxide /
The black matrix was formed through the steps of etching the chromium film, removing the resist, washing and drying. Next, the following photosensitive material composition containing a radical polymerization type photopolymer, a pigment and a solvent as main components was prepared. Binder: Benzyl methacrylate-methacrylic acid copolymer Monomer: Pentaerythritol tetraacrylate Initiator: 4- [pN, N-di (ethoxycarbonylmethyl)]-2,6-di (trichloromethyl) -S-
Triazine pigment: Anthraquinone-based red pigment (CI: a mixture of Pigment Red 177 and Pigment Yellow 139 having a submicron particle size) Solvent: Ethyl 3-ethoxypropionate The obtained photosensitive material composition is subjected to final heat treatment. After the completion, the coating was applied to a thickness of 2.0 μm. After pre-baking at 100 ° C., exposure was performed using a red pattern forming mask, development, washing, and drying, followed by post-baking at 200 ° C. to form red colored pixels.

Next, a phthalocyanine green pigment (C
I: a mixture of Pigment Green 7 and Pigment Yellow 83) in a composition similar to that used for the red photosensitive material;
It was applied so as to have a thickness of 0 μm, and simultaneously with the colored pixels, a green column having a size of 15 μm × 25 μm was formed on the red colored pixels on the black matrix portion.

Next, a phthalocyanine blue pigment (C
I: a mixture of Pigment Blue 15: 3 and Pigment Violet 23) was applied to a thickness of 2.0 μm after the final heat treatment. 1
After pre-baking at 00 ° C., exposure using a blue pattern forming mask, development, washing and drying, followed by 200 ° C.
With post-baking to form green colored pixels,
On the columnar body formed in the black matrix part, 12
A blue colored layer for forming a columnar portion having a size of × 22 μm was formed. The substrate on which the colored pixels were formed was attached to a parallel plate type plasma CVD apparatus, and the diameter of the substrate electrode: 650 mm The distance between the electrodes: 50 mm High frequency power: 50 kHz, 500 W Reactive gas flow rate: 300 sccm Reactive gas component (volume ratio) Silane: ammonia : Nitrogen =
50: 50: 200 Film forming pressure 0.2 torr Film forming rate 25 nm / min. Film forming was performed for 10 minutes at a substrate temperature of 180 ° C. to obtain a silicon nitride film having a thickness of 0.25 μm. The silicon nitride film had a good coverage of the step portion and was uniformly formed, and was uniformly laminated on each colored pixel.

Example 2 A black matrix was formed on glass in the same manner as in Example 1. Next, the same red, green,
After completion of the final heat treatment, each of the blue photosensitive material compositions was applied to a thickness of 1.5 μm to form a colored pixel of each color. Next, photocurable acrylate oligomer (o-cresol novolak epoxy acrylate (molecular weight 1500 to 2000)) 50 parts by weight Multifunctional monomer (dipentaerythritol hexaacrylate DPHA manufactured by Nippon Kayaku) 50 parts by weight Photopolymerization initiator (Irgacure 907 manufactured by Ciba Geigy Co., Ltd.): 2 parts by weight Solvent: ethyl cellosolve acetate: 200 parts by weight
It was applied to a thickness of 5.0 μm. This is 150
After pre-baking at ℃, the display pixels were exposed using a mask having a columnar pattern formed in the other part, developed, washed and dried, and then post-baked at 200 ° C. to a size of 15 × 25 μm. A columnar body was formed. Except for the portion where the columnar body was formed, thermal curing occurred by pre-baking, and a 0.2 to 0.3 μm protective film was formed so as to flatten the unevenness between the colored layers.

Since the formed protective film does not contain a pigment, a dye or the like, it is possible to prevent the liquid crystal from being contaminated by the pigment, the dye or the impurities contained therein. Because of the flattened protective film, unevenness between the colored layers was eliminated, and the spacing between the counter substrate and each color was uniform. In this example,
Although the protective film is formed using thermosetting, the protective film can be formed by controlling the amount of exposure in consideration of the remaining film ratio of the photosensitive material. For example, two exposures, that is, exposure on the entire surface and exposure using a mask on which a columnar body is formed,
It is also possible to adjust the film thickness of the columnar part and other parts.

[0023]

According to the present invention, in a liquid crystal display device in which liquid crystal is sandwiched between two substrates, a coloring layer is laminated on a non-display area on a color filter constituting the liquid crystal display device. While forming a columnar body to maintain the interval,
Since a protective film containing no impurities is formed on the entire surface of the color filter, the spacer does not move when a voltage is applied or when the carrier is transported, so that the alignment film and the TFT can be prevented from being damaged. Thus, problems such as uneven display are eliminated. Further, there is no elution of impurities from the colored layer of the color filter into the liquid crystal, and a high-quality image can be obtained for a long period of time. In particular, a liquid crystal display device suitable for a system in which liquid crystal is driven in a plane parallel to a display surface can be obtained.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of a liquid crystal display device of the present invention.

[Explanation of symbols]

1 ... substrate, 2 ... black matrix, 3 ... colored pixel,
3R: red colored pixel, 3G: green colored pixel, 3B: blue colored pixel, 4G: green column, 4B: blue column, 5 ...
Inorganic compound thin film

Claims (3)

[Claims] 1. A color filter, comprising: a non-display portion having a columnar body for maintaining a liquid crystal sandwiching interval by lamination of colored pixels; and a protective film made of a non-conductive inorganic compound. 2. A color filter, wherein a non-display portion has a columnar body for holding a liquid crystal sandwiching interval with a transparent photosensitive material, and a portion other than the columnar body is formed of a protective material made of the transparent photosensitive material. A color filter having a film. 3. The color filter according to claim 1, wherein the inorganic compound is at least one selected from a silicon nitride, a silicon oxide, and a composite oxide of a metal.