Patent ID: 7087270
Filing Date: 2006-08-08
Classification: C09K,G02F

Abstract:
1. A method of making a liquid crystal alignment layer for bistable nematic liquid crystal devices comprising two confinement plates provided respectively on both sides of a nematic liquid crystal layer, said liquid crystal alignment layer having a low zenithal and a strong azimuthal anchoring energies for the liquid crystal layer over at least one of its confinement plates, said method comprising: depositing a copolymer of Poly(vinyl chloride) and poly(vinylacetate), to form said liquid crystal alignment layer, onto one of the two confinement plates; stabilizing the polymer deposit, the stabilization comprising at least one thermal annealing step at a temperature below the melting point and higher than the vitreous transition temperature of the polymer deposit and an ultraviolet light exposure in the range of 180 nm to 400 nm after said thermal annealing; and defining an azimuth orientation for the deposit to induce strong and controlled azimuth anchoring of the liquid crystal, the zenithal anchoring being characterized by a critical electric field for breaking the anchoring below 10 V/μm, the azimuthal anchoring being characterized by an extrapolation length less than 100 nm.