JP4361654B2 - Liquid crystal panel and manufacturing method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal panel and a manufacturing method thereof, and more particularly to a liquid crystal panel manufactured by lithography and electrodeposition and a manufacturing method thereof.
[0002]
[Prior art]
In recent years, personal computers and monitors have become popular due to the rapid development of information and multimedia. As a solution to reduce environmental pollution, it has been proposed to replace the display tube with a liquid crystal display (LCD) as the primary display device. Therefore, it is required that the LCD should be as high in display quality as the display tube. However, there are many problems to be overcome to reach this goal.
[0003]
The liquid crystal panel, particularly the color liquid crystal panel shown in FIG. 1, includes a color filter substrate 10, a liquid crystal drive substrate 8, and a liquid crystal material 9 divided into cells in a gap between the color filter substrate 10 and the liquid crystal drive substrate 8. The cell gap (usually several microns to several tens of microns in length) is formed by the spacer 7. Conventionally, this spacer is a plastic or glass pellet dispersed on the second conductive film 2 '. In such a method, it is difficult to evenly distribute the pellets on the second conductive film 2 ′, resulting in nonuniform cell gaps and poor display quality, especially in large display panels. . Furthermore, since the pellets may be distributed on the red filter 4, the green filter 5 and the blue filter 6, the light may be scattered and the contrast may be deteriorated. Furthermore, while the liquid crystal material 9 is being filled, the pellets may move through the cell and cut the drive wire.
[0004]
U.S. Pat. No. 4,874,461 discloses a liquid crystal display panel in which spacers are manufactured by photolithography. These spacers are easy to drop off because the photocuring process during manufacture may be incomplete, and the sizes are not uniform. Japanese Examined Patent Publication No. 6-222370 discloses a streak spacer. The resolution is poor due to the use of negative photoresist, and the spacer pattern is limited.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a liquid crystal panel in which the thickness and uniformity of spacers are easily controlled, the cell gap is small, and the display quality is excellent.
[0006]
Another object of the present invention is to provide a liquid crystal panel in which no spacer is placed on an effective display filter and display quality can be improved.
[0007]
A further object of the present invention is to provide a liquid crystal panel manufacturing method capable of effectively controlling the thickness and uniformity of spacers. A small and uniform cell gap could be obtained.
[0008]
Another further object of the present invention is to provide a method of manufacturing a liquid crystal panel in which the spacers are all arranged on a black matrix rather than on an effective display filter.
[0009]
A still further object of the present invention is to provide an improved method for manufacturing liquid crystal panels. The method improves product yield and display quality and can be applied to large area LCDs.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a liquid crystal driving substrate, a color filter substrate disposed under the liquid crystal driving substrate, a liquid crystal material disposed between the liquid crystal driving substrate and the color filter substrate, and a plurality of liquid crystal materials. The color filter substrate is disposed on a glass substrate, a first conductive film disposed on the glass substrate, a plurality of types of color filters, a black matrix, and the plurality of types of color filters. A second conductive film, wherein each of the plurality of types of color filters is partitioned by a black matrix, the plurality of spacers are disposed on an area limited by the black matrix, and A liquid crystal panel in which the bottom surface of the spacer is in contact with the first conductive film is disclosed. In a preferred embodiment of the present invention, the plurality of spacers are polymer compositions and are made by an electrodeposition method, and the thickness thereof is controlled by the electrodeposition method. These spacers are black or opaque resin cured by light or heat. Alternatively, the spacers are transparent or colored resins that are cured by light or heat.
[0011]
In order to achieve the above object, the present invention provides a liquid crystal driving substrate, a color filter substrate disposed under the liquid crystal driving substrate, a liquid crystal material disposed between the liquid crystal driving substrate and the color filter substrate, and a plurality of liquid crystal materials. The method of manufacturing the color filter substrate includes a step of manufacturing a glass substrate, a first conductive film disposed on the glass substrate, a plurality of types of color filters, a black matrix, and a color filter. A plurality of types of color filters and a plurality of spacers apply a four-level photoresist on the first conductive film, and the photoresist is first applied to the first conductive film. The red, green and blue areas are produced by exposing with a four level reticle and repeating development and electrodeposition. Exposure using a pacer reticle, exposing the first conductive film in a region limited by the black matrix by development, and forming an electrodeposition coating composition on the exposed first conductive film The manufacturing method of the liquid crystal panel manufactured by this is disclosed. In another embodiment of the invention, the electrodeposition coating composition is a light or thermosetting resin that is black or opaque, or a transparent or colored light or thermosetting resin. The position and size of the spacer are determined by a spacer reticle, and the spacer thickness of the spacer is controlled by the composition of the electrodeposition composition for spacer production and the electrodeposition conditions. The four-level photoresist is a positive photosensitive resin.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a liquid crystal panel having a plurality of types of color filters (4, 5, 6) and a liquid crystal driving substrate 8 arranged at a predetermined distance from the filters by a plurality of spacers 7. The plurality of spacers 7 are made of a polymer electrodeposition paint, and the paint may be a black paint or a colorless paint used to form a black matrix. Carbon black described in Japanese Patent No. 36622 may be used. The plurality of spacers may be made of a red, green, or blue paint described in Japanese Patent Publication No. 2-36622. In other words, the plurality of spacers are black electrodeposition paint or non-black electrodeposition paint.
[0013]
These spacers may be made of the same material as the black matrix when the black matrix is formed by electrodeposition. However, when a chrome black matrix plate (hereinafter referred to as “CrBM plate”) is applied, these spacers may be colored. This black matrix is formed from chromium by photolithography. However, black spacers are preferred to avoid light dispersion.
[0014]
A process for manufacturing a plurality of spacers in an area limited by the black matrix will be described below.
[0015]
1. Formation of Color Filter After the transparent conductive film 2 is formed on the transparent substrate 1 or the chrome black matrix (CrBM) substrate, the four-level photoresist described in US Pat. No. 5,641,595 (ie, 4 A gradation developing photoresist (hereinafter referred to as “MDPR” for short) is applied onto the substrate. The material of the transparent conductive film 2 and the method of applying MDPR are described in US Pat. No. 5,641,595.
[0016]
The MDPR is exposed to ultraviolet light, but the MDPR is exposed by a four-level reticle (that is, a four-tone mask, hereinafter referred to as “MDPM” for short) or a color filter (4, 5, 6). Mask in advance with reticles of different intensities. Next, the red, green and blue portions (4, 5, 6) of the color filter are electrodeposited on the respective areas of the conductive film 2. These areas are formed by repeatedly developing MDPR using MDPM having patterns with different light transmittances. During the development, the portion of the conductive film 2 is exposed using the MDPM having the highest light transmittance and gradually using the one having the lower light transmittance. The order of electrodeposition of various colors on the exposed conductive film is not fixed. Unlike the conventional technique, each colored portion of the color filter (4, 5, 6) is completed by one-step exposure.
[0017]
2. Formation of Spacer In the second exposure step, the spacer reticle shown in FIG. 4 is used to form a spacer. The light will pass through the light transmissive area 41 to expose the MDPR and be blocked by the light masking area 42. After the development, the transparent first conductive film 2 used for electrodeposition of the spacer 51 is exposed. Next, the exposed portions of the transparent second conductive film 2 are electrodeposited at a high voltage and a high temperature using a polymer electrodeposition composition to form a spacer 51.
[0018]
3. After the formation of the black matrix spacer, the substrate 10 is exposed to ultraviolet light, and the remaining MDPR is removed by development. When the substrate having the transparent conductive film 2 is used, the black matrix is formed by electrodeposition of a black polymer electrodeposition composition on the area where the MDPR has been removed. If a substrate with CrBM is used, no further processing is required after MDPR development since the black matrix is formed on the substrate from the beginning.
[0019]
Further, when a substrate having CrBM is used, since the substrate itself is conductive, a two-level positive photosensitive photoresist is applied on the substrate by spinning instead of the four-level positive photosensitive photoresist. The spacer reticle shown in FIG. 4 is used in exposed areas to form spacers on a substrate having CrBM after exposure and development. The plurality of spacers 7 are formed by electrodeposition at a high voltage and a high temperature for a long time. The substrate is then exposed to ultraviolet light to remove any remaining photoresist. A color filter having a plurality of spacers is thus formed.
[0020]
【Example】
The invention is explained in more detail in the following examples. The MDPR, red, green and blue part electrodeposition paints used are disclosed in US Pat. No. 5,641,595. The black polymer electrodeposition paint used is described below.
[0021]
<Production example of black polymer electrodeposition paint>
The polyester resin, black pigment, and titanium oxide were mixed in advance with a dissolution stirrer and then dispersed with a DCP disperser. After dilution with ion-exchanged water, a black polymer electrodeposition paint BM-98 containing 10% by weight of a solid component was produced. Table 1 shows the composition.
[0022]
[Table 1]
Table 1: Composition of BM-98
Raw material composition %
Pigment 1 Degussa SP-550 12.5
Pigment 2 Titanium oxide (Dupont R-706) 4.1
Polyester resin Shinto Paint S-453 29.8
Melamine resin Mitsui cyanamide cymel 232 11.0
Neutralizer DIPA 3.0
Solvent 1 PGM 3.0
Solvent 2 DAA 34.0
Antifoaming agent Surfynol 104 1.0
Dispersant BYK-190 1.6
Total 100.0
[0023]
Example 1
FIG. 2 shows a cross-sectional diagram of a liquid crystal panel formed by electrodeposition using MDPR according to one embodiment of the present invention.
[0024]
Formation of color filter MDPR (not shown in the figure) on a first transparent conductive film (ITO) 2 having a thickness of 0.18 μm provided on a glass substrate 1 having a thickness of 0.7 mm Is applied by a spin coater. After drying at 90 ° C. for 20 minutes, a positive photosensitive photoresist having a thickness of 2.0 μm was formed. The MDPR was exposed to ultraviolet light having a density of 250 mj / cm ² . The ultraviolet light was generated by a high pressure mercury exposure apparatus and masked by a four level reticle MDPM.
[0025]
Development was performed with a 0.3 wt% potassium hydroxide solution, and the MDPR exposed with ultraviolet light that passed through the pattern on the MDPM having a light transmittance of 100% was selectively developed. The patterned conductive film (usually indium tin oxide (hereinafter referred to as ITO)) was exposed. After washing with water and drying, an anionic red electrodeposition paint R-75 manufactured by Chemitron was applied to the exposed area of the conductive film using the transparent substrate as an anode at a paint temperature of 25 ° C. and a DC voltage of 48V. Electrodeposition was performed under the condition of seconds. After rinsing with ion exchange water and drying at 100 ° C. for 10 minutes, a red electrodeposition film having a thickness of 1.7 μm was formed, and the red portion 4 of the color filter shown in FIG. 2 was completed.
[0026]
Next, the second development proceeded with a 0.6 wt% potassium hydroxide solution to selectively develop the MDPR exposed by the ultraviolet light that passed through the MDPM having a light transmittance of 40%. Another ITO was exposed. After washing with water and drying, an anionic green electrodeposition paint G-74 manufactured by Chemitron Co., Ltd. was applied at a paint temperature of 25 ° C. and a direct current voltage of 64 V over the exposed area of the conductive film using this transparent substrate as an anode. Electrodeposition was performed under working conditions of seconds. After rinsing with ion exchange water and drying at 100 ° C. for 10 minutes, a green electrodeposition film having a thickness of 1.7 μm was formed, and the green portion 5 of the color filter shown in FIG. 2 was completed.
[0027]
Next, the third development proceeded with a 1.0 wt% potassium hydroxide solution to selectively develop the MDPR exposed by the ultraviolet light that passed through the MDPM having a light transmittance of 20%. Yet another ITO was exposed. After washing and drying, an anionic blue electrodeposition paint B-74 manufactured by Chemitron was used for 19 seconds under a direct current voltage of 25 ° C. and 54 V on the exposed area of the conductive film using this transparent substrate as an anode. The electrodeposition was performed under the working conditions. After rinsing with ion exchange water and drying at 100 ° C. for 10 minutes, a blue electrodeposition film having a thickness of 1.7 μm was formed, and the blue portion 6 of the color filter shown in FIG. 2 was completed.
[0028]
Formation of spacers So far, the remaining MDPRs are present on the substrate on which the red, green and blue portions are formed. Next, the substrate was exposed to ultraviolet light having a density of 100 mj / cm ² while being masked with a spacer reticle. The exposed MDPR is selectively developed with a 1.0 wt% potassium hydroxide solution to expose a portion of the conductive film (ITO). After washing with water and drying, an anionic black electrodeposition paint BM-98 manufactured by Chemitron was used for 25 seconds under a direct current voltage of 27 ° C. and 70 V on the exposed area of the conductive film using this transparent substrate as an anode. Electrodeposition was performed under the working conditions. After rinsing with ion-exchanged water and drying at 100 ° C. for 10 minutes, a 7.0 μm thick black spacer electrodeposition film was formed, and the spacer 7 shown in FIG. 2 was completed.
[0029]
Forming a black matrix <br/> exposed the entire substrate with ultraviolet light of density 1000 mj / cm ^2. The remaining MDPR was developed with a 1.5 wt% potassium hydroxide solution to expose a conductive film (ITO) with no electrodeposition composition on top. After washing with water and drying, an anionic black electrodeposition paint BM-98 manufactured by Chemitron Co., Ltd. was used on the ITO, using the transparent substrate as an anode, at a coating temperature of 25 ° C. and a DC voltage of 30 V for 10 seconds. I electrodeposited. After rinsing with ion exchange water and drying at 100 ° C. for 10 minutes, a black matrix electrodeposition film having a thickness of 1.9 μm was formed, and the black matrix 3 shown in FIG. 2 was completed. The OD value is 3.0, which is appropriate for light shielding.
[0030]
Production of liquid crystal display panel A second transparent conductive film 2 'was formed on the color filter substrate 10. A liquid crystal material 9 (for example, a TFT liquid crystal composition) was filled between this substrate and a liquid crystal driving substrate 8 (for example, a TFT plate). Although the liquid crystal panel is manufactured in this way, the change in the cell gap is small. No spacer is formed on the effective display portion. In this way, excellent display quality could be obtained.
[0031]
Example 2
FIG. 3 is a sectional view of a liquid crystal panel according to another embodiment of the present invention. A chrome black matrix plate was used as the substrate.
[0032]
Formation of a color filter MDPR (shown in the figure) on a 0.18 mm thick first transparent conductive film 2 and a chrome black matrix 3 placed on a 0.7 mm thick glass substrate 1 Is applied with a spin coater. The chromium black matrix 3 was originally formed on the substrate. After drying at 90 ° C. for 20 minutes, a positive photosensitive photoresist having a thickness of 2.0 μm was formed. In forming the color filter, the procedure of Example 1 was followed.
[0033]
Formation of spacer The spacer 7 shown in FIG. 3 was completed according to the procedures of Example 1.
[0034]
Forming a black matrix <br/> exposed the entire substrate with ultraviolet light of density 1000 mj / cm ^2. The remaining MDPR was developed with a 1.5 wt% potassium hydroxide solution to expose the ITO together with the chromium film. Subsequent procedures were the same as the procedures exemplified in Example 1.
[0035]
Example 3
A color filter having red, green, and blue portions was formed on a CrBM plate manufactured by STI by a pigment dispersion method. In order to fabricate the spacer, UV light having a density of 200 mj / cm ² masked by using the spacer reticle shown in FIG. 4 was applied onto the positive photosensitive photoresist spin-coated on the substrate. The exposed MDPR was selectively developed with a 1.0 wt% potassium hydroxide solution, thereby exposing the chromium film. After washing with water and drying, an anionic black electrodeposition paint BM-98 manufactured by Chemitron was electrodeposited on the chromium film under the working conditions of a paint temperature of 27 ° C. and a DC voltage of 70 V for 25 seconds. After rinsing with ion exchanged water and drying at 100 ° C. for 10 minutes, a 7.0 μm thick black spacer was formed.
[0036]
【The invention's effect】
The spacer 51 could be effectively manufactured by using MDPR and electrodeposition on the black matrix 52 shown in FIG. This liquid crystal panel exhibits excellent display quality with a small cell gap and less change. Furthermore, since these spacers are formed not on the effective display portion but on the black matrix, the display quality is excellent, and the display quality due to the spacers should not be deteriorated.
[0037]
It will be apparent that various modifications and changes can be made to the invention disclosed above without departing from the scope and spirit of the invention. Therefore, the applicant defines this invention only by the matters described in the above claims.
[Brief description of the drawings]
FIG. 1 is a cross-sectional diagram of a conventional liquid crystal panel.
FIG. 2 is a cross-sectional view of a liquid crystal panel according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a liquid crystal panel according to another embodiment of the present invention.
FIG. 4 depicts a spacer reticle.
FIG. 5 depicts a spacer over a black matrix.
[Explanation of symbols]
1 Transparent substrate 2 Transparent conductive film (first)
2 'Transparent conductive film (second)
3 Black matrix 4 Red portion 5 Green portion 6 Blue portion 7 Spacer 8 Liquid crystal drive substrate 9 Liquid crystal material 10 Color filter substrate

Claims (12)

A liquid crystal driving substrate, a color filter substrate disposed under the liquid crystal driving substrate, a liquid crystal material disposed between the liquid crystal driving substrate and the color filter substrate, and a liquid crystal panel including a plurality of spacers, A color filter substrate includes a glass substrate, a first conductive film disposed on the glass substrate, a plurality of types of color filters, a black matrix, and a second conductive film disposed on the plurality of types of color filters. Each of the plurality of types of color filters is partitioned by the black matrix, the plurality of spacers are disposed on an area limited by the black matrix, and bottom portions of the plurality of spacers The liquid crystal panel is in contact with the first conductive film.   The liquid crystal panel according to claim 1, wherein the plurality of spacers are a polymer composition and are electrodeposited.   The liquid crystal panel according to claim 1, wherein the thickness of the plurality of spacers is controlled by electrodeposition.   The liquid crystal panel according to claim 1, wherein the plurality of spacers are black or opaque resin cured by light or heat.   The liquid crystal panel according to claim 1, wherein the plurality of spacers are transparent or colored resin cured by light or heat. A liquid crystal panel comprising: a liquid crystal driving substrate; a color filter substrate disposed under the liquid crystal driving substrate; a liquid crystal material disposed between the liquid crystal driving substrate and the color filter substrate; and a plurality of spacers. A method of manufacturing the color filter substrate, comprising: a glass substrate; a first conductive film disposed on the glass substrate; a plurality of types of color filters; a black matrix; and the plurality of types of color filters. includes arranged step of producing the second conductive film, the plurality of kinds of color filters and a plurality of spacers,
A four-tone developable photoresist is applied on the first conductive film,
The photoresist is first exposed using a four-tone mask,
Produce red, green and blue areas by repeating development and electrodeposition,
This photoresist is then exposed using a spacer reticle,
Exposing the first conductive film in a region limited by the black matrix by development, and forming an electrodeposition coating composition on the exposed first conductive film;
The above-mentioned method manufactured by.   The method for producing a liquid crystal panel according to claim 6, wherein the electrodeposition coating composition is a black or opaque resin cured by light or heat.   The method for producing a liquid crystal panel according to claim 6, wherein the electrodeposition coating composition is a transparent or colored resin cured by light or heat.   The method for manufacturing a liquid crystal panel according to claim 6, wherein the position and size of the spacer are determined by the spacer reticle.   The manufacturing method of the liquid crystal panel of Claim 6 which controls the thickness of the said spacer by the electrodeposition coating composition for spacer manufacture.   The method of manufacturing a liquid crystal panel according to claim 6, wherein all of the plurality of spacers are arranged on an area limited by a black matrix.   The method for producing a liquid crystal panel according to claim 6, wherein the four-tone developable photoresist is a positive photosensitive resin.

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