Optical film and polarizing plate

Abstract

There has been a demand for an optical film having excellent glass-range photoelastic coefficient and a polarizing plate which uses this optical film. The present invention provides an optical film which is characterized by containing an ester-based resin that contains 50% by mole or more of a fumaric acid ester residue unit represented by formula (1) and having a negative birefringence, and a photoelasticity regulator having a positive birefringence, and which is also characterized in that the absolute value of the glass-range photoelastic coefficient thereof is 5×10−12 Pa−1 or less. (In the formula, each of R1 and R2 independently represents a linear alkyl group having 1 to 12 carbon atoms, a branched alkyl group having 3 to 12 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms.)

Dependencies are inferred from the claim text.