JP2002286921A - Liquid crystal display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device of which the lower order domain is prevented from being generated and which carries out an excellent color display by reducing projection and recession based on construction of a color filter and by increasing uniformity of liquid crystal layer thickness. SOLUTION: The liquid crystal display device is characterized by having peripheral parts of a resin black matrix 4 superposed on peripheral parts of respective color filter patterns 5a, 5b, 5c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display device for displaying a color image, and more particularly to a liquid crystal display device having a color filter pattern and a resin black matrix, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a color filter substrate constituting a conventional liquid crystal display device. After the resin black matrix 4 is formed on the substrate, red color filter patterns 5a and green and blue color filter patterns 5b and 5c are respectively formed. When forming the color filter pattern, a part of the color filter pattern is formed so as to overlap with the resin black matrix so that no gap is formed at the boundary with the resin black matrix 4. Thereafter, the transparent electrode pattern 2 is arranged, and the liquid crystal material 6 is sealed between the substrate 1b on which the liquid crystal alignment processing of the alignment film 3 has been performed and the counter substrate 1a.

[0003]

In a conventional method of manufacturing a liquid crystal display device, a resin black matrix for eliminating light leakage in a display area and a resin black matrix for forming three color filter patterns are used. Therefore, there is an advantage that positional deviation hardly occurs because each color filter pattern has the same shape. However, the color filter pattern superposed on the resin black matrix, particularly the green color filter pattern, easily transmits the i-line, which is the sensitivity region of the photocurable resin, as compared with the resin black matrix, so that it is easily exposed and cured, A pattern edge portion overlapping with the resin black matrix causes a steep step. In addition, not only the green color filter pattern but also the red and blue color filter patterns are more easily exposed and cured than the resin black matrix, and a step structure is formed at each edge.

Since the edge of the pattern becomes steep, a change in the thickness of the liquid crystal layer between the pattern substrate and the counter substrate occurs rapidly. Starting from the stepped portion, a lower-order domain of display abnormality, which is caused by the rotation angle of the liquid crystal being reduced by 180 degrees from the target value, is likely to occur. In addition, physical contact such as a rubbing step performed as an alignment process is insufficient on the steep side surface of the pattern edge, so that the alignment force for controlling the liquid crystal layer is reduced and display abnormalities are likely to occur.

As shown in FIG. 2, when the liquid crystal display device is a reflection type liquid crystal display device having a reflection layer 7, light L incident from an observer side is reflected by the reflection layer 7 and is reflected by a color filter pattern. When the light is emitted through the steep step portion, there is a problem in display quality that the step of the color filter pattern becomes more prominent on the observer side.

Accordingly, the present invention provides a liquid crystal display device capable of preventing the occurrence of low-order domains by reducing unevenness due to the above-described color filter structure and increasing the uniformity of the thickness of the liquid crystal layer, and performing good color display. The purpose is to do.

[0007]

In order to achieve the above object, the liquid crystal display of the present invention employs the following color filter structure. An edge of the resin black matrix overlaps an edge of each color filter pattern. Further, it is preferable that the thickness of the resin black matrix is smaller than the thickness of the color filter pattern.

Further, the present invention is characterized in that it is a reflection type liquid crystal display device in which a reflection layer is provided on a substrate provided with a color filter pattern.

Further, the manufacturing method is such that after forming a color filter pattern of a plurality of colors on a substrate, the color of the resin black matrix at a portion where the color filter pattern is not formed is smaller than that of the color filter pattern. The resin black matrix material is placed on the filter pattern and the substrate, and the resin black matrix material is exposed, and the color filter pattern and the resin black matrix are overlapped so that the edge of the resin black matrix overlaps the edge of the color filter pattern. Are formed.

[Operation] FIG. 1 is a sectional view of a liquid crystal display device according to the present invention. A blue color filter pattern 5a and red and green color filter patterns 5b and 5c are formed on the color filter side substrate 1b, and then a resin black matrix 4 is formed so as to overlap the edge of each color filter pattern. Thereafter, a transparent electrode 2 and an alignment film 3 are formed, and a liquid crystal layer 6 is sealed between the transparent substrate 2 and the counter substrate 1b.

Since the resin black matrix uses a photosensitive resin, it is cured by irradiating light, but is harder to be exposed than a color filter pattern. Therefore, even after the exposure and curing steps, the edge, which is the edge, has a gentler shape than the edge of the color filter pattern. Therefore, as described above, when the color filter pattern is formed by overlapping after forming the resin black matrix, the color filter pattern is easily exposed and cured, so that the edge is cut and the edge has a steep shape. On the contrary, if the resin black matrix is formed after forming the color filter pattern, the edge becomes gentle, so that a steep step does not occur at the overlapping portion. In particular, by making the thickness of the resin black matrix thinner than that of the color filter pattern, the step at the overlapping edge can be reduced.

Since the edge portion of the color filter pattern is covered with a resin black matrix, a steep step of the color filter pattern can be reduced to prevent a sudden change in the thickness of the liquid crystal layer. The planarization prevents alignment instability due to insufficient rubbing.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid crystal display device according to the best mode for carrying out the present invention will be described below. As shown in FIG. 3, a glass substrate 1b on which a color filter is to be formed
Then, a color filter resist material to be the first color blue color filter 5a is dropped, and spin-coated with a spin coater to a constant film thickness. The color filter resist material is prepared by dispersing a blue pigment and a photosensitive agent in an acrylic resin, and has a viscosity of 6.5 mPa · s in a solvent and a solid concentration of 19.5%.
The negative resist material was adjusted to a film thickness of 1.5 μm by spin coating at 450 rpm for 15 seconds. Further, after evaporating the solvent component by baking at 90 ° C. for 2 minutes, ultraviolet exposure is performed through a photomask 8a corresponding to the blue pattern, and the corresponding pattern is photoreaction cured.

Then, with a 0.2% aqueous solution of sodium carbonate,
After immersion for one minute and development, the excess color filter resist was removed, and the blue color filter pattern 5a was formed as shown in FIG.
It is obtained as follows.

Subsequently, as shown in FIG. 5, a color filter resist material for the second color filter pattern 5b is dropped and spin-coated with a spin coater. The color filter resist material is prepared by dispersing a red pigment and a photosensitizer in an acrylic resin and adjusting the viscosity to 6.0 mPa · s and the solid content concentration of 20.8% with a solvent. The film thickness is 1.5 μm at 400 rpm for 15 seconds. Is formed. At this time, the color filter resist material is applied to the entire surface of the glass substrate 1b.
A step occurs at a thickness of from 0.7 m to 0.7 μm. When the pattern position of the second color is formed in contact with the color filter 5a of the first color, the photomask 8b is affected by this step.
Are exposed to ultraviolet rays at intervals, so that they are not affected by steps.

As in the case of the first color, a 0.2% aqueous solution of sodium carbonate is immersed for 1 minute, and development is performed to remove the excess color filter resist, and a red color filter pattern 5b is obtained as shown in FIG.

Further, as shown in FIG. 7, a color filter resist material of the third color filter 5c is dropped and spin-coated with a spin coater. The color filter resist material is prepared by dispersing a green pigment and a photosensitive agent in an acrylic resin, and has a viscosity of 6.5 mPa · s in a solvent and a solid content of 19.0%.
The film thickness was adjusted to 1.5 at 450 rpm for 15 seconds.
μm is formed. Similarly to the process of the second color, the color filter resist material of the third color forms a step with a thickness of 0.5 μm to 0.7 μm on the patterns 5 a and 5 b of the first color and the second color. Since ultraviolet light exposure is performed at an interval from the color pattern, the film is formed without being affected by a step.

As shown in FIG. 8, sodium carbonate 0.2
% Aqueous solution is immersed for 1 minute to remove the excess color filter resist to obtain three color filter patterns.

Next, as shown in FIG. 9, a resist material for the resin black matrix 4 is dropped and spin-coated with a spin coater. A resin black resist material is prepared by dispersing a black pigment and carbon particles and a photosensitive agent in an acrylic resin, and has a viscosity of 5.6 mPa · s and a solid concentration of 24.5% in a solvent.
The film thickness was adjusted at 1,000 rpm for 15 seconds.
0 μm is formed. The resin black has a step on the three color filter patterns 5a, 5b and 5c. However, since the rotation speed of the spin coater is higher than the rotation speed at the time of forming the color filter pattern, the film thickness on which the resin black rides is limited. It fits within a step of 0.2 μm or less. After evaporating the solvent component by baking at 90 ° C. for 2 minutes, the substrate is exposed to ultraviolet light with a photomask 8d so that no gap is formed between the color filter patterns 5a, 5b and 5c.

A 0.2% aqueous solution of sodium carbonate is immersed in the solution for 1 minute to perform development, and an excess resin black resist material is removed, followed by baking at 200 ° C. for 90 minutes to obtain a resin black pattern 4 shown in FIG. .

Thereafter, the transparent electrode pattern 2 shown in FIG. 11 is formed, and the orientation film 3 is formed, thereby completing the color filter side substrate. Further, as shown in FIG. 12, a reflective layer 7 may be provided between each color filter pattern and the substrate 1b to form a reflective liquid crystal display device.

[0022]

In the color filter and the resin black matrix formed according to the present invention, since the concave portion on the surface is shallow, the contact in the rubbing step performed as the liquid crystal alignment process is performed uniformly, and the occurrence of defective alignment is eliminated. Further, since the steep inclination of the edge portion of the color filter pattern is reduced, a sharp change in the thickness of the liquid crystal layer is reduced, and the generation of low-order domains is prevented. In addition, since the uniformity of the thickness of the liquid crystal layer is increased, the shutter performance of the liquid crystal is improved, and a higher quality liquid crystal display device can be provided.

Further, even in the case of a reflection type liquid crystal display device, the thickness of the color filter pattern does not change at any point, so that a reflection type liquid crystal display device having good color quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view of a conventional liquid crystal display device.

FIG. 3 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 4 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 5 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 6 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 7 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 8 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 9 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 10 is a sectional view showing a manufacturing process in the liquid crystal display device of the present invention.

FIG. 11 is a cross-sectional view illustrating a manufacturing process in the liquid crystal display device of the present invention.

FIG. 12 is a cross-sectional view illustrating a manufacturing process in the liquid crystal display device of the present invention.

[Explanation of symbols]

 1a Opposite-side substrate 1b Color filter-side substrate 2 Transparent electrode 3 Alignment film 4 Resin black matrix 5a Blue color filter pattern 5b Red color filter pattern 5c Green color filter pattern 6 Liquid crystal layer 7 Reflective film 8a Photomask for blue color filter pattern 8b Red Photomask for color filter pattern 8c Photomask for green color filter pattern 8d Photomask for resin black matrix pattern

Claims (4)

[Claims] 1. A liquid crystal display device comprising a plurality of color filter patterns for displaying a color image and a resin black matrix between each color filter pattern on the same substrate, wherein an edge of each color filter pattern is provided. A liquid crystal display device, wherein an edge of the resin black matrix overlaps the upper portion. 2. The resin black matrix according to claim 1, wherein
The liquid crystal display of claim 1, wherein the thickness of the color filter pattern is smaller than the thickness of the color filter pattern. 3. The liquid crystal display device according to claim 1, wherein a reflective layer is provided on a substrate provided with the color filter pattern. 4. After forming a color filter pattern of a plurality of colors on a substrate, the color filter is formed such that a resin black matrix at a portion where the color filter pattern is not formed is thinner than the color filter pattern. On the pattern and on the substrate, a resin black matrix material is provided, the resin black matrix material is exposed, and the color filter pattern is exposed so that the edge of the resin black matrix overlaps the edge of the color filter pattern. And a resin black matrix.