Coating processes – Direct application of electrical – magnetic – wave – or... – Polymerization of coating utilizing direct application of...
Reexamination Certificate
1996-07-10
2001-05-08
Pianalto, Bernard (Department: 1762)
Coating processes
Direct application of electrical, magnetic, wave, or...
Polymerization of coating utilizing direct application of...
C427S248100, C427S261000, C427S265000, C427S269000, C427S287000, C427S294000, C427S488000, C427S535000, C427S578000
Reexamination Certificate
active
06228435
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for treating a base such as glass, on which light-shielding members have been partially formed, to impart water repellency to the surfaces of the light-shielding members, and a light-shielding member formed substrate obtained by this treating process. In particular, the present invention relates to a production process of a color filter having excellent color characteristics and good surface evenness, and a color filter substrate for picture device produced by this process.
2. Related Background Art
As an example of picture devices, a liquid crystal color filter used in a liquid crystal display device is composed of many picture units one of which is formed of pixels of three primary colors of red, green and yellow formed on a transparent base. In order to enhance display contrast, light-shielding regions having a fixed width are provided between the individual pixels. In general, these light-shielding regions are black and designated black matrices.
The production processes of a color filter include a dyeing process in which a dyeable medium formed using a photolithographic technique is dyes, a process using photosensitive compositions in which a pigment has been dispersed, and an electrodeposition process making good use of a patterned electrode. Besides, as production processes of low cost, there are processes in which colored areas are formed by a printing method or an ink-jet method, and the like.
In the printing process or ink-jet process, by which a color filter can be provided as low cost, among the conventional production processes, it has been proposed to make good use of black matrices, which can be formed in advance by a photolithographic method, in order to prevent blurring of the individual colored regions and color mixing between adjoining colored regions to realize high-precision coloring. Therefore, it is necessary to prevent the spread of colorants outside the coloring regions intended to a material from which the black matrices are formed.
For example, Japanese Patent Application Laid-Open No. 59-75205 discloses a technique in which an ink-jet system is used to provide three colors of coloring matter on a base. In order to prevent the spread of the coloring matter outside the region intended, the paper publication states that the formation of a diffusion-preventing pattern with a substance hard to wet is effective. However, no specific technique regarding this is disclosed. Besides, even Japanese Patent Application Laid-Open No. 62-106407, which relates to a production process of a color filter by the printing process, recommends the use of inks hard to wet partition walls. However, selecting materials to form inks which easily wet a base, but hardly wet partition walls is difficult. In Japanese Patent Application Laid-Open No. 4-195101, there is disclosed a technique in which black matrices are formed from a photosensitive resin layer (generally called a positive resist) and a silicone rubber layer in that order. The black matrices are used as a mask when exposing the base from the back side of the base and developing, thereby simultaneously removing the photosensitive resin layer and the silicone rubber layer formed thereon at their exposed potions to form patterned partition walls conforming to with the black matrices. The surfaces of said partition walls are composed of a silicone rubber layer having water and oil repellency.
In the above photolithographic process, exposure is conducted from the side opposite to the black matrices, so that the alignment control of a photomask with a substrate found in the fabrication process of LSI is unnecessary. However, this process requires use of expensive materials such as the photosensitive resin and silicone rubber, and naturally needs coating steps for forming the photosensitive resin layer and the silicone rubber layer. As a result, the raw material cost and the number of steps increase, which ultimately causes a lowering in yield.
Silane coupling agents have heretofore been widely used as bonding agents between an organic material and an inorganic material and for imparting water repellency and dispersibility to materials. In general, the silane coupling agents have been used by diluting them with a solvent such as an aromatic hydrocarbon, an aliphatic hydrocarbon, or a halogenated hydrocarbon such as flon, to prepare a solution, which is applied to a surface of a base by dipping or spraying, and dried. The process using such solvents has required environmental and fireproofing measures against gases produced from waste liquids and is not preferred. Further, a fitting method to a dipping jig has become a problem in the processing of optical parts. Therefore, Japanese Patent Application Laid-Open No. 6-122776 has reported a dry treatment process for imparting, in particular, water repellency, wherein a silane coupling agent such as a fluoroalkylsilane is introduced into a vacuum container in which a base to be processed has been arranged, and plasma discharge is produced by radio-frequency or direct current, thereby providing a water-repellent layer on the surface of the base processed.
However, a detailed investigation by the present inventors as to the water-repellent surface provided by the process disclosed in Japanese Patent Application Laid-Open No. 6-122776 has revealed that a difference in water repellency arises according to the materials of bases to be processed. The measured values thereof are shown in Table 1.
TABLE 1
Material
Contact angle with water
Green flat glass
105 ± 3
7059
105 ± 5
Molybdenum
120 ± 2
tantalum
120 ± 3
Chromium
120 ± 3
(Note)
7059: Trade name of glass manufactured by Corning Co.
It has heretofore been said that when a silane coupling agent is applied to the surface of a dielectric such as glass and the surface of a metal such as molybdenum or tantalum by a wet process, the silane coupling agent is easier to fix on the glass surface rather than on the metal surface, and so the silane coupling agent is more effective for the glass surface. However, the measurement results shown in Table 1 have revealed that when the silane coupling agent is applied by a dry process using plasma reaction, the reverse is true.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a process for treating a base to selectively impart water repellency thereto, a light-shielding member formed substrate and a color filter substrate for picture device, by which the above problems involved in the prior art can be solved.
Another object of the present invention is to provide a process for treating a base to selectively impart water repellency thereto in such a manner that the areas of a light-shielding layer have high water repellency, while the other areas have low water repellency.
A further object of the present invention is to provide a light-shielding member formed substrate wherein inks of different colors can be fully spread over respective pixel parts to color them, and the inks do not mix with each other because light-shielding members having high water repellency are arranged between adjoining pixels.
A still further object of the present invention is to provide a color filter substrate wherein a difference in water repellency between regions in which light-shielding members are arranged, and the other regions is made larger in order for inks to be stably held on the other regions.
A yet still further object of the present invention is to provide a production process of a color filter substrate, by which yield is enhanced.
The present invention, by which the above objects can be achieved, has the following constitution.
According to the present invention, there is thus provided a process for treating a base to selectively impart water repellency thereto, which comprises forming a water-repellent layer composed of a silane coupling agent on a base on which light-shielding members are partially formed, and then exposing the surface of the base
Iwata Kenichi
Kameyama Makoto
Matsuhisa Hirohide
Osano Nagato
Suzuki Hiroyuki
Canon Kabushiki Kaisha
Pianalto Bernard
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