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AssigneeEastman Kodak Company
InventorsYongcai Wang, Janglin Chen, Charles C. Anderson, Timothy J. Hubert, Timothy C. Schunk, Richard A. Castle
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The invention generally relates to polymer films used as protective cover sheets for polarizer plates, a method for producing polarizing plates, and a Liquid Crystal Display employing the same. More particularly, the invention relates to a cover sheet composite having a removable, carrier substrate and a cover sheet comprising a low birefringence polymer film and a layer that promotes adhesion to polyvinyl alcohol on the same side of the carrier substrate as the low birefringence polymer film. The guarded cover sheet of the invention is less susceptible to defects due to dirt and abrasion during the manufacture of the cover sheet and polarizer plates. In addition, the cover sheet has excellent adhesion to polyvinyl alcohol-containing dichroic films and eliminates the need to alkali treat the cover sheet prior to lamination to the dichroic films.
A method of forming a polarizing plate comprising (a) providing two guarded cover sheet composites each comprising a carrier substrate and a cover sheet comprising a layer promoting adhesion to polyvinyl alcohol and a low birefringence polymer film comprising polymeric material having an in-plane birefringence Δnin of less than about 1×10−4 and an out-of-plane birefringence Δnth of from 0.005 to −0.005, (b) providing a dichroic film, and (c) simultaneously bringing said cover sheets into contact with said dichroic film such that the layer promoting adhesion to polyvinyl alcohol in each of said two cover sheets is in contact with said dichroic film.
Dependencies are inferred from the claim text.