Patent ID: 8304079
Filing Date: 2012-11-06
Classification: C08F,C08J,G02B,G02F,Y10T

Abstract:
1. A positive birefringence layer made from a non-stretched, non-photopolymerized polymer film for use in liquid crystal displays, the film being stable at ambient conditions, the film having a positive birefringence Δn=n z −(n x +n y )/2 that is greater than 0.002 throughout the wavelength range of 400 nm<λ<800 nm, wherein n x and n y represent in-plan refractive indexes, and n z represents the thickness-direction refractive index of the film, the film having been cast onto a substrate from a solution of a soluble polymer having a moiety of wherein R wherein Ar-BES is an optically anisotropic subunit (OASU) that is attached directly to the polymer backbone via one covalent bond, wherein Ar is an aromatic ring structure, BES represents at least one birefringence enhancing substituent; wherein the Ar-BES is oriented perpendicular to the polymer backbone, and the higher the perpendicularity of the Ar-BES, the larger the value of the positive birefringence of the polymer film.