Patent ID: 6348245
Filing Date: 2002-02-19
Classification: C08G,C09K,G02F,Y10T

Abstract:
An alignment layer for liquid crystal displays made by the method comprising the steps of:a) forming a solution from a solvent and substantially equimolar amounts of an aromatic tetracarboxylic dianhydride component containing 3,3â€²,4,4â€²-benzophenone tetracarboxylic dianhydride and at least one aromatic diamine component of the group of the formula AI to AIII â€ƒwherein R1 to R4 are alkyl groups containing from 1 to 4 carbon atoms and R5 to R8, which can be the same or different, are selected from the group hydrogen and alkyl groups containing 1 to 4 carbon atoms, with the proviso that at least two of R5 to R8 are alkyl groups; b) polymerizing the aromatic tetracarboxylic dianhydride and the at least one aromatic diamine component to form a poly(amic) acid solution; c) imidizing the poly(amic) acid in the solution to form polyimide and removing the polyimide therefrom; d) casting the polyimide onto a substrate to form a thin coating layer; and e) exposing the thin coating layer of polyimide to polarized electromagnetic radiation.