Method for producing polarizer
AssigneeNitto Denko Corporation
InventorsHiroaki Sawada, Takeharu Kitagawa, Takashi Kamijo
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Abstract
A method for producing a polarizer comprises the steps of: (A) stretching a polyvinyl alcohol-based resin layer to obtain a stretched layer; (B) immersing the stretched layer in a dyeing liquid containing iodine to obtain a dyed layer 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 so that the absorbance of the dyed layer decreases by 0.03 to 0.7, provided that the absorbance of the dyed layer is controlled so that it does not become less than 0.3.
Claims12
A method for producing a polarizer including a polyvinyl alcohol-based resin layer, the method comprising in order the steps of:
- (A) stretching a polyvinyl alcohol-based resin layer to obtain a stretched layer including crystallized portions and non-crystallized portions of polyvinyl alcohol;
- (B) immersing the stretched layer in a dyeing solution containing iodine for a time period sufficient to obtain a dyed layer in which iodine is adsorbed to said crystallized portions of polyvinyl alcohol in the form of polyiodine complex as well as to said non-crystallized portions to provide an absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0, wherein the dyed layer has a thickness ranging from 0.4 microns (μm) to about 7 μm;
- and
- (C) preferentially removing a part of iodine adsorbed to the non-crystallized portions in the dyed layer to reduce the absorbance, determined in step B, of the dyed layer by 0.03 to 0.7, and preventing the absorbance of the dyed layer from becoming less than 0.3.
A method for producing a polarizer including a polyvinyl alcohol-based resin layer, the method comprising in order the steps of:
- (A) stretching a polyvinyl alcohol-based resin layer to obtain a stretched layer including crystallized portions and non-crystallized portions of polyvinyl alcohol;
- (B) immersing the stretched layer in a dyeing solution containing iodine for a time period sufficient to obtain a dyed layer in which iodine is adsorbed to said crystallized portions of polyvinyl alcohol in the form of polyiodine complex as well as to said non-crystallized portions to provide an absorbance thereof determined from a tristimulus value Y is from 0.4 to 1.0, wherein the dyed layer has a thickness ranging from 0.4 microns (μm) to about 7 μm;
- (C) preferentially removing a part of iodine adsorbed to the non-crystallized portions in the dyed layer to reduce the absorbance, determined in step B, of the dyed layer by 0.03 to 0.7, and preventing the absorbance of the dyed layer from becoming less than 0.3;
- and
- (D) immersing the layer in a crosslinking liquid after removing the part of iodine adsorbed to the non-crystallized portion.
Dependencies are inferred from the claim text.