Poly-Vinyl-Alcohol polarizer based on adsorbed iodine

摘要

A polarizer (20) comprises a dyed stretched layer of polyvinyl alcohol-based resin having a thickness in the range 0.4 to 7 µm, said resin having crystallized portions (17) oriented in the stretching directing having preferentially adsorbed thereto polyiodine ion complexes (19) and has an absorbance in the range 0.3 to 0.4 and a polarization degree of 99.95% or higher. 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.