Norihisa Moriya

Retardation-controlling color filter with two directly stacked retardation layers

— A polymerizable liquid crystal (PLC), the orientation of which can be frozen, is useful for making retardation layers. In this paper, a new color filter (CF) with retardation-controlling layers made of PLC is reported. It has a positive A-plate and a negative C-plate, both directly stacked on a color-filter layer. These two retardation layers exhibit good orientation ability, and function well as retarders, even when they are only 1/10 or less as thick as ordinary retardation films. The new CF also has excellent thermal stability. The change in retardation after heat treatment at 200°C for 30 min is around 5%, and there is no observable peeling. A prototype VA-LCD made with our new CF provides good optical compensation, with the light leakage being extremely low in all azimuthal directions. This technology is very useful for making thin, highly reliable color filters for LCDs, even with other modes.