Dopant-induced contrast enhancement of vertically aligned liquid crystal cells

A simple method is developed for aligning the laterally difluorinated high birefringence liquid crystal (LC) compounds and mixtures in a homeotropic cell. Adding a few percent positive dielectric anisotropic or nonpolar LC material not only enhances the contrast ratio but also improves the overall figure-of-merit. Several negative LC compounds with a wide variation of birefringence are used to investigate this phenomenon. Molecular modeling and experimentation are demonstrated to support this concept.