Patent ID: 8877304
Filing Date: 2014-11-04
Classification: C08G,C08J,C09K,G02F,Y10T

Abstract:
1. An optical film which is made of a polycarbonate copolymer consisting essentially of a unit (A2) represented by the following formula: and a unit (B1) represented by the following formula: wherein an (A2/B1) molar ratio of the unit (A2) to the unit (B1) is 20/80 or more and less than 40/60 and which satisfies the following expression (1): wherein R(450), R(550) and R(650) are retardation values within a plane of the film at wavelengths of 450 nm, 550 nm and 650 nm, respectively, wherein a 5% weight loss temperature (Td) by heat of the polycarbonate copolymer is 380° C. or higher, and wherein an absolute value of photoelastic constant of the film is not more than 20×10