Incremental printing of symbolic information – Ink jet – Fluid or fluid source handling means
Reexamination Certificate
1999-02-16
2002-07-09
Barlow, John (Department: 2853)
Incremental printing of symbolic information
Ink jet
Fluid or fluid source handling means
C347S096000
Reexamination Certificate
active
06416174
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an ink composition, a pattern forming method and a color filter, and particularly to an ink composition used to form a pattern by an ink-jet method, a pattern forming method which uses the above ink composition, and a color filter which is produced by the pattern forming method using the above ink composition.
2. Description of the Related Art
The pattern forming method according to the ink-jet method sprays droplets of an ink composition onto a base material by various types of ink composition ejecting methods such as an electrostatic attraction method, a method which employs a piezoelectric element to mechanically vibrate or bias ink, or a method of heating to foam ink and using a pressure by the foamed ink to form a pattern on the surface of the base material. And, the pattern forming method according to the ink-jet method has advantages that a pattern can be formed quickly without involving production of large noise, and a multi-colored pattern can be formed easily. Therefore, it is attracting attention in many fields.
Meanwhile, color filters h are used for display units such as a CRT, a liquid crystal display and a plasma display, or a solid state image pickup device and the like have been produced by various types of methods such as a pigment dispersion method, a dye dispersion method, and a dyeing method.
For example, Japanese Patent Laid-Open Publication No. Hei 7-179711 describes a method of producing a fluorescent film with a filter by forming a patterned photo absorption layer on the inner face of a face plate, applying a pigment dispersed solution and a phosphor slurry, and exposing through a mask and developing. And, Japanese Patent Laid-Open Publication No. Sho 59-75205 describes a method of producing a color filter by forming a colored layer on a substrate by the ink-jet method.
However, the method of producing a fluorescent film with a filter described in Japanese Patent Laid-Open Publication No. Hei 7-179711 has a disadvantage that the production cost is high because it involves many steps to produce the fluorescent film, and the application of a pigment dispersed solution and a phosphor slurry and the exposure through a mask and development are required for each color. And, the method of producing a color filter described in Japanese Patent Laid-Open Publication No. Sho 59-75205 which forms a colored layer on a substrate by the ink-jet method has disadvantages that a dispersion preventive pattern or a wettability improver must be formed on a glass substrate in advance, increasing facilities investment and the number of processes, also increasing the production cost, and lowering a production yield.
The present invention has been completed in view of the above circumstances, and aims to provide an ink composition which can form a fine pattern on the surface of glass, ceramics or polyester resins by the ink-jet method without requiring to form a wettability improver.
The present invention also aims to provide a pattern forming method which can easily form a fine pattern efficiently on the surface of a glass substrate or the like, and does not involve many processes or facilities investment, so that the formed pattern excels in reliability and economy.
Besides, the present invention aims to provide a color filter having a pattern which excels in optical resistance and water resistance and has high reliability in practical use, and which also excels in economy.
SUMMARY OF THE INVENTION
An ink composition according to the present invention is controlled to keep maximum the ratio (V/S) of the volume (V) of a system which consists of a solvent, a pigment dispersed into the solvent and a dispersant which is dispersed into the solvent to enhance an affinity between the solvent and the pigment; and the surface area (S) of an interface of the system produced on a boundary between the system and a gas phase.
And, an ink composition according to the present invention has a system which consists of a solvent, a pigment dispersed into the solvent and a dispersant which is dispersed into the solvent to enhance an affinity between the solvent and the pigment, and the system has (1) a surface tension of 20.0 dyn/cm to 50.0 dyn/cm at 25° C., and (2) a viscosity of 1.5 cp to 20.0 cp at 25° C.
Besides, an ink composition according to the present invention contains a solvent, a pigment dispersed into the solvent, a dispersant which is dispersed into the solvent to enhance an affinity between the solvent and the pigment, and an additive which is dispersed into the solvent to control free energy of an interface.
A pattern forming method according to the invention has a step of ejecting from a nozzle by an ink-jet method droplets of an ink composition of which the ratio (V/S) between the volume (V) of a system which consists of a solvent, a pigment dispersed into the solvent and a dispersant which is dispersed into the solvent to enhance the affinity between the solvent and the pigment; and the surface area (S) of the interface of the system produced on at the boundary between the system and a gas phase is controlled to be kept at a maximum, a step of adhering the droplets onto the surface of a base material, and a step of adhering the pigment contained in the droplets onto the base material.
And, a pattern forming method according to the invention has a step of ejecting from a nozzle by an ink-jet method droplets of an ink composition having a system which consists of a solvent, a pigment dispersed into the solvent and a dispersant which is dispersed into the solvent to enhance an affinity between the solvent and the pigment, and which has (1) a surface tension of 20.0 dyn/cm to 50.0 dyn/cm at 25° C. and (2) a viscosity of 1.5 cp to 20.0 cp at 25° C., a step of adhering the droplets onto the surface of a base material, and a step of adhering the pigment contained in the droplets onto the base material.
Furthermore, a pattern forming method according to the invention has a step of ejecting from a nozzle by an ink-jet method droplets of an ink composition containing a solvent, a pigment dispersed into the solvent, a dispersant which is dispersed into the solvent to enhance an affinity between the solvent and the pigment, and an additive which is dispersed into the solvent to control free energy of an interface, a step of adhering the droplets onto the surface of a base material, and a step of adhering the pigment contained in the droplets onto the base material.
A color filter according to the invention has a base material and a colored layer which is formed of a pigment adhered to the surface of the base material by an ink-jet method.
Generally, to form a pattern of picture elements for a color filter by an ink-jet method, when a base material has a surface (to-be-colored layer) of glass, ceramics or a film material made of polyester resin or the like which is different from fiber of paper or the like, a conventional ink composition is not adequately adhered to the surface of such a base material, and the ink composition is repelled or spreads on the surface of the base material. And, since the adhesion of a coloring matter to the surface of the base material is weak, it is easily separated from the surface of the base material, and the formed pattern is broken in a short period. The base material used herein generally means those having a to-be-colored layer surface, onto which the coloring matter of the ink composition is adhered, with a structure of glass, ceramics or a film made of polyester resin or the like which is different from fiber of paper or the like. Therefore, the base materials belonging to such a category can be a glass substrate or a ceramics substrate; various types of film materials such as polyester resin, diacetate resin, triacetate resin, acrylic resin, polycarbonate resin, polyvinyl chloride resin, polyimide resin, cellophane or celluloid; and coated paper of which the surface is coated with organic polymer compounds such as polyamide or polyester.
FIG.
2
A and
FIG. 2B
Ito Takeo
Nakazumi Hiroyuki
Sakai Kazuo
Barlow John
Kabushiki Kaisha Toshiba
Shah M
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