Optical: systems and elements – Glare or unwanted light reduction – With absorption means
Reexamination Certificate
2001-09-05
2002-06-04
Sikder, Mohammad (Department: 2872)
Optical: systems and elements
Glare or unwanted light reduction
With absorption means
C359S613000, C359S610000, C359S599000
Reexamination Certificate
active
06398371
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an antiglare film, a method for producing the same, a polarizer and a liquid crystal display using the same.
BACKGROUND OF THE INVENTION
In image displays such as CRT, PDP and LCD, an antiglare film or an antiglare antireflection film is generally arranged at outermost surface of a display for the purpose of preventing the reduction of contrast due to the reflection of an outer light and the reflection of an image.
The particles of an inorganic or organic polymer are used in a coating solution for forming the antiglare hard coat layer of an antiglare film or an antiglare antireflection film for giving an antiglare property. When a solvent which swells and dissolves a triacetyl cellulose support is used as a solvent composition in a coating solution for the antiglare hard coat layer for obtaining adhesion of the triacetyl cellulose support and the antiglare hard coat layer, the particles for giving antiglare property are partially buried in the support, thus a sufficient antiglare property cannot be obtained. While when a coating solution for the antiglare hard coat layer is prepared with a solvent which does not dissolve a triacetyl cellulose support, sufficient adhesion cannot be obtained, although antiglare property can be obtained, so that there arises a problem in either case.
SUMMARY OF THE INVENTION
An object of the present invention is to provide an antiglare film having sufficient antiglare property compatible with sufficient adhesion of a support and an antiglare hard coat layer by merely forming an antiglare hard coat layer on a triacetyl cellulose transparent support, further to provide an antiglare film having an antireflection ability by providing a low refractive index layer.
Another object of the present invention is to provide a polarizer and a liquid crystal display using the above film.
The above objects of the present invention have been achieved by an antiglare film, a polarizer and a liquid crystal display each having the constitution described below.
1. An antiglare film comprising a triacetyl cellulose transparent support having provided thereon one or more hard coat layers including an antiglare hard coat layer, wherein the hard coat layer contiguous to the triacetyl cellulose transparent support is formed from a coating solution comprising solvents comprising one or more solvents which dissolve the triacetyl cellulose support and one or more solvents which do not dissolve the triacetyl cellulose support.
2. The antiglare film as described in the above item 1, wherein at least one of the solvents which do not dissolve the triacetyl cellulose support has higher boiling point than the boiling point of at least one of the solvents which dissolve the triacetyl cellulose support.
3. The antiglare film as described in the above item 2, wherein the temperature difference of the boiling point between the solvent having the highest boiling point of the solvents which do not dissolve the triacetyl cellulose support and the solvent having the highest boiling point of the solvents which dissolve the triacetyl cellulose support is 30° C. or more.
4. The antiglare film as described in the above item 1, 2 or 3, wherein the antiglare hard coat layer is formed by crosslinking by ionizing radiation.
5. The antiglare film as described in the above item 1, 2, 3 or 4, wherein a penta-functional or more functional acrylate monomer which is crosslinked by ionizing radiation is at least used as the component for forming the antiglare hard coat layer.
6. The antiglare film as described in any of the above items 1 to 5, wherein the triacetyl cellulose transparent support is a triacetyl cellulose film formed by casting a triacetyl cellulose dope prepared by dissolving a triacetyl cellulose in a solvent not substantially containing a dichloromethane by means of a single layer-casting process.
7. The antiglare film as described in any of the above items 1 to 5, wherein the triacetyl cellulose transparent support is a triacetyl cellulose film formed by casting a triacetyl cellulose dope prepared by dissolving a triacetyl cellulose in a solvent by means of a multilayer-casting process.
8. The antiglare film as described in any of the above items 1 to 7, wherein particles having an average particle size of from 1.0 to 5.0 &mgr;m are dispersed in the antiglare hard coat layer.
9. The antiglare film as described in the above item 8, wherein the particles dispersed in the antiglare hard coat layer are spherical organic polymer particles.
10. The antiglare film as described in any of the above items 1 to 9, wherein the antiglare hard coat layer has a refractive index of from 1.50 to 2.00.
11. The antiglare film as described in any of the above items 1 to 10, wherein the antiglare hard coat layer comprises a cured product of the composition containing a monomer having two or more ethylenic unsaturated groups and the particles of the oxide of at least one kind of a metal selected from the group consisting of titanium, aluminum, indium, zinc, tin, antimony and zirconium having particle size of 0.1 &mgr;m or less.
12. The antiglare film as described in any of the above items 1 to 11, wherein a low refractive index layer having a refractive index of from 1.35 to 1.45 is provided as an antireflection layer as an outermost layer on the side of the support on which at least one hard coat layer is provided, and the haze value of the antiglare film is 3.0% or more.
13. The antiglare film as described in the above item 12, wherein the low refractive index layer comprises a cured product of the composition comprising a fluorine-containing compound which is crosslinked by heat or ionizing radiation and inorganic fine particles, and the integrating sphere average reflectance of from 450 to 650 nm of the antiglare film is 2.3% or less.
14. The antiglare film as described in the above item 13, wherein the inorganic fine particles have an average particle size of from 0.001 to 0.1 &mgr;m.
15. The antiglare film as described in the above item 13 or 14, wherein the inorganic fine particles are silica.
16. The antiglare film as described in the above item 13, 14 or 15, wherein the fluorine-containing compound is a polymer obtained by polymerizing a fluorine-containing vinyl monomer.
17. The antiglare film as described in any of the above items 1 to 16, wherein the triacetyl cellulose transparent support is a triacetyl cellulose formed by multilayer-casting of a triacetyl cellulose.
18. A method for producing an antiglare film comprising a triacetyl cellulose transparent support having provided thereon one or more hard coat layers including an antiglare hard coat layer, wherein the hard coat layer contiguous to said triacetyl cellulose transparent support is formed from a coating solution comprising solvents comprising one or more solvents which dissolve said triacetyl cellulose support and one or more solvents which do not dissolve said triacetyl cellulose support.
19. The method for producing an antiglare film as described in the above item 18, wherein at least one of the solvents which do not dissolve the triacetyl cellulose support has higher boiling point than the boiling point of at least one of the solvents which dissolve the triacetyl cellulose support.
20. The method for producing an antiglare film as described in the above item 19, wherein the temperature difference of the boiling point between the solvent having the highest boiling point of the solvents which do not dissolve the triacetyl cellulose support and the solvent having the highest boiling point of the solvents which dissolve the triacetyl cellulose support is 30° C. or more.
21. The method for producing an antiglare film as described in the above item 18, 19 or 20, wherein the antiglare hard coat layer is formed by crosslinking by ionizing radiation.
22. The method for producing an antiglare film as described in the above item 18, 19, 20 or 21, wherein a penta-functional or more functional acrylate monomer which is crosslinked by ionizing radiation is at least used as the component
Matsunaga Naohiro
Nakamura Kazuhiro
Burns Doane , Swecker, Mathis LLP
Sikder Mohammad
LandOfFree
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