Fabrication of new photoreactive vertical alignment thin layers for fast switching liquid crystal display

Abstract

New photoreactive vertical alignment layers have been fabricated by spin coating the mixtures of polyimide (PI) and bi-functional monomers on the indium tin oxide substrate. Post ultraviolet (UV) surface treatment under electric field induced fast electro-optical switching of liquid crystal (LC) through formation of pre-tilted alignment layer. To investigate the effect of reactive monomers on the electro-optical properties of LC device, newly designed four types of monomers with different aromatic cores and photoreactive groups were applied to PI mixtures. Stable homeotropic alignment and fast response time in the LC device were achieved with a simple coating and subsequent UV process of monomer with both a phenyl core and methacrylic groups in the PI layer and it yields electro-optical performance superior to that achieved with the conventional PI alignment layer. This elegant approach provides a stable and fast switching LC alignment layer for high performance LC displays.