Patent ID: 8821994

Claim:
An optical retardation compensation film having a proper wavelength dispersion curve wherein R 450 /R 550 is 1.20 to 2.00, R 550 /R 650 is 1.10 to 1.60, and R 650 /R 750 is 1.00 to 1.40, wherein R 450 , R 550 , R 650 and R 750 are the retardation values in the thickness direction of the optical compensation film at the wavelengths 450 nm, 550 nm, 650 nm, and 750 nm, respectively; wherein the optical film has a positive birefringence value throughout the wavelength range of 400 nm<λ<800 nm, wherein the film is cast from a solution comprising a polymer composition having a polymer segment with a polymer backbone, a light stable optically anisotropic sub-unit (OASU) attached directly to the polymer backbone via at least one covalent bond, wherein the OASU is capable of orienting perpendicular to the polymer backbone, and the higher the perpendicularity of the OASU, the larger the value of the positive birefringence of the polymer film.