Patent ID: 8377558

Claim:
A non-stretched, non-photopolymerized polymer film for use in positive birefringence layers in liquid crystal displays, the film being stable at ambient conditions, the film having a positive birefringence greater than 0.002 throughout the wavelength range of 400 nm<λ<800 nm, the film having been cast on a substrate from a solution of a soluble polymer comprising: a polymer segment having a polymer backbone, a light-stable optically anisotropic sub-unit (OASU) attached directly to the polymer backbone through a single covalent bond, wherein the OASU is oriented perpendicular to the polymer backbone, and the higher the perpendicularity of the OASUs, the larger the value of the positive birefringence of the polymer film, wherein the polymer comprises a moiety of wherein R 1 , R 2 , and R 3 are each independently hydrogen atoms, alkyl groups, substituted alkyl groups, or halogens.