Method for producing polarizer
AssigneeNitto Denko Corporation
InventorsHiroaki Sawada, Takeharu Kitagawa, Takashi Kamijo
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Abstract
A method for producing a polarizer (20) comprises the steps of: (A) stretching a polyvinyl alcohol-based resin layer (10) to obtain a stretched layer (14); (B) immersing the stretched layer (14) in a dyeing liquid (23) containing iodine to obtain a dyed layer (18) in which absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0 (transmittance T=40% to 10%); and (C) removing a part of iodine adsorbed in the dyed layer (18) so that the absorbance of the dyed layer (18) decreases by 0.03 to 0.7, provided that the absorbance of the dyed layer (18) is controlled so that it does not become less than 0.3.
Claims7
A polarizer comprising a stretched layer of polyvinyl alcohol-based resin including iodine adsorbed therein;
- wherein said layer of polyvinyl alcohol-based resin has a thickness of 0.4 to 7 μm and includes polymer chains oriented substantially in a given direction being the direction of stretching, said polymer chain including a crystallized portion of polyvinyl alcohol-based resin oriented substantially in said given direction, and said layer of polyvinyl alcohol-based resin surrounding the crystallized portion of said polyvinyl alcohol-based resin is amorphous;
- and
- wherein said iodine adsorbed in said layer of polyvinyl alcohol-based resin is present in said layer of polyvinyl alcohol-based resin in the form of polyiodine ion complex adsorbed to the crystallized portion of said layer of polyvinyl alcohol-based resin, whereby the polarizer exhibits an absorbance in the range of from 0.3 to 0.4 and said polyiodine ion complex adsorbed to the crystallized portion of said layer of polyvinyl alcohol-based resin provides the polarizer with dichrosim within a visible light range.
Dependencies are inferred from the claim text.