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US 8,709,192 B2Granted
Protective cover sheet comprising a UV-absorbing layer for a polarizer plate and method of making the same
AssigneeNitto Denko Corporation
InventorsYongcai Wang, Hwei-Ling Yau, Timothy J. Hubert, Alain E. Gros, Timothy C. Schunk, Paul M. Hoderlein
Life of this patent
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Abstract
The invention relates to a protective cover sheet comprising a low birefringence protective polymer film and a layer that promotes adhesion to poly(vinyl alcohol), the protective cover sheet comprising at least one functional layer containing a UV-absorbing polymer.
Claims4
A method of forming a polarizing plate comprising:
- (A) providing at least one guarded cover sheet composites comprising:
- (i) a carrier substrate;
- and
- (ii) a protective cover sheet comprising a low birefringence protective polymer film having in-plane birefringence, Δnin of less than 1×10−4 and an out-of-plane birefringence Δnth of 0.005 to −0.005 and, in addition, one or more functional layers, which layers are either adjacent or non-adjacent each other, wherein the one or more functional layers comprise at least an adhesion-promoting layer for adhering a poly(vinyl alcohol)-containing film to the low birefringence protective polymer film, wherein the functional layers do not comprise a polarizing film, wherein the adhesion-promoting layer which is a functional layer comprises a UV-absorbing polymer, and wherein the adhesion-promoting layer is coated onto the carrier substrate and then dried, prior to application of the low birefringence protective polymer film;
- (B) providing a poly(vinyl alcohol)-containing dichroic film;
- (C) removing the carrier substrate from the guarded cover sheet composite after formation of the protective cover sheet;
- and
- (D) bringing the protective cover sheet into contact with the poly(vinyl alcohol)-containing dichroic film such that the adhesion-promoting layer in the protective cover sheet is in contact with the poly(vinyl alcohol)-containing dichroic film.
5 more elements
A method of forming a polarizing plate comprising:
- providing two guarded cover sheet composites each comprising a protective cover sheet comprising a low birefringence protective polymer film having in-plane birefringence, Δnin of less than 1×10−4 and an out-of-plane birefringence Δnth of 0.005 to −0.005 and, in addition, one or more functional layers, which layers are either adjacent or non-adjacent each other, wherein the one or more functional layers comprise at least an adhesion-promoting layer for adhering a poly(vinyl alcohol)-containing film to the low birefringence protective polymer film, wherein the functional layers do not comprise a polarizing film, wherein the adhesion-promoting layer which is a functional layer comprises a UV-absorbing polymer, and wherein the adhesion-promoting layer is coated onto a carrier substrate and then dried, prior to application of the low birefringence protective polymer film;
- providing a poly(vinyl alcohol)-containing dichroic film, and simultaneously or sequentially bringing said cover sheets into contact with said poly(vinyl alcohol)-containing dichroic film such that the adhesion-promoting layer for adhering a poly(vinyl alcohol)-containing film to the low birefringence protective polymer in each of the two cover sheets is in contact with the poly(vinyl alcohol)-containing dichroic film, and
- removing carrier substrates from the guarded cover sheet composites after formation of the protective cover sheets.
Dependencies are inferred from the claim text.