Process and materials for aligning liquid crystals and liquid crystal optical elements

摘要

A process for inducing alignment of a liquid crystal medium adjacent to a surface of an optical alignment layer comprising: exposing at least one optical alignment layer to polarized light; the polarized light having a wavelength within the absorption band of said optical alignment layer; wherein the exposed alignment layer induces alignment of the liquid crystal medium at an angle + and - theta with respect to the direction of the polarization of the incident light beam and along the surface of the optical alignment layer; and applying a liquid crystal medium to the optical alignment layer, wherein the optical alignment layer is a polyimide comprising an an amine component having a 2-substituted 1,4-benzenediamine wherein the 2-substituent X1 is an electron withdrawing group having a positive sigma . Also claimed is a liquid crystal display element made by the process.