Vertical alignment of high birefringence and negative dielectric anisotropic liquid crystals for projection displays

Abstract

Physical properties and alignment performance of biphenyl and terphenyl negative dielectric anisotropic liquid crystal (LC) compounds are investigated. Results show biphenyl compounds align well in homeotropic LC cells and the alignment of terphenyls are relatively poor. We have developed a new method to align these high birefringence LC compounds. Adding a few percent of positive dielectric anisotropic or nonpolar LC material not only enhances the contrast ratio but also improves the overall figure-of-merit. Molecular modeling and experimentation are demonstrated to support this concept.