Viewing angle compensation of various LCD modes by using a liquid crystalline polymer film Nisseki LC film

Abstract

We have developed liquid crystalline retardation films to improve quality of images of LCDs such as their viewing angle performance and coloration. We have achieved to make many types of optical retardation films by using rod-like liquid crystalline polymer (LCP). The resulting liquid crystalline polyesters film has several advantages over conventional uni- or biaxial stretched retardation film. Optical well-controlled structures such as twisted nematic, hybrid nematic and homeotropic structures could be stabilized for ideal compensation of various LCD modes including TN, STN, ECB, VA and IPS modes. Twisted nematic film is effective to cancel coloration in STN mode that is a fatal drawback for color representation. Hybrid nematic film is quite unique film because the film works not only as a wave plate but also as a viewing angle compensator for TN and ECB modes. By using rod-like LCP, it is also possible to make negative-C plate and positive-C plate. Negative-C plate could be realized by using a short pitch cholesteric alignment and positive-C plate could be realized by using homeotropic alignment. Viewing angle performances of various LCD modes compensated with the LCP films are reported in this study.