Liquid Crystal Display Matrices, Drive Schemes and Bistable Displays

Liquid crystal displays (LCDs) are a dominant display technology, and have the advantages of flat panel, low weight, energy-saving and low drive voltage. This chapter first discusses segmented displays, passive matrix displays and its drive scheme, and active matrix displays. It then explains bistable liquid crystals and their drive schemes. In the surface stabilized ferroelectric liquid crystal (SSFLC) display, the liquid crystal is sandwiched between two crossed polarizers. There are several types of bistable nematic LCDs that have good performance characteristics. They are twisted-untwisted (TN) bistable nematic LCD, zenithal bistable nematic LCD, surface-induced bistable nematic LCD, mechanically bistable nematic LCD and bistable STN-LCD. Cholesteric (Ch) liquid crystals have a helical structure in which the liquid crystal director twists around a perpendicular axis named the helical axis. The optical properties of a cholesteric liquid crystal depend on the orientation of the helical axis with respect to the cell surface.