Optical element, process for producing the same, substrate for liquid crystal alignment, liquid crystal display device, and birefringent material

摘要

There are provided an optical element, which can be produced at low cost and has birefringent characteristics with low susceptibility to heat, and a process for producing the same. The optical element comprises: a light transparent substrate; and a first birefringence layer provided on the substrate, wherein the first birefringence layer comprises a crosslinked polymer comprising a coupling agent and/or a surfactant which can homeotropically align a polymerizable liquid crystal comprising rodlike molecules; and the crosslinked polymer has a three-dimensionally crosslinked structure in such a state that the polymerizable liquid crystal comprising rodlike molecules holds homeotropic alignment.