Improvement of Optical Compensated Bend (OCB) and Vertical Alignment (VA) Mode Liquid Crystal Displays by Nano-alignment Technique

Abstract

Surface-modified silicon oxide (SiO(2)) nanoparticles containing surfactants with amino end-groups were synthesized. The amounts of surfactants anchoring on SiO(2) nanoparticles were characterized to research 8 wt% by thermogravimetric analysis (TGA). The characteristic amino peak of surfactants on SiO(2) nanoparticles can also be confirmed by nuclear magnetic resonance (NMR) spectroscopy. By spin-coating reactive surface-modified SiO(2) nanoparticles on the pre-cured polyimide (PI), amino end-groups of the surfactants can be further reacted with pre-cured PI layer over the ITO surface by thermo-curing. Moreover, the distribution of post-cured nanoparticles in the optical compensated bend (OCB) and vertical alignment (VA) cells have been investigated by scanning electron microscope (SEM). As a result, the newly developed nano-alignment technique with different process conditions, such as various particle sizes and concentrations, can be applied to improve the threshold voltage, response time, and pre-tilt angle in the OCB and VA mode liquid crystal display (LCD) cells.