Transient Dielectric Study of Bistable Reflective Cholesteric Displays and Design of Rapid Drive Scheme08/28/1995
Transient dielectric measurement is used to study the transitions among the planar, focal conic, and homeotropic states of cholesteric liquid crystals. If the initial state is the field-induced homeotropic state, at low bias fields, the liquid crystal transforms to the planar state in a sequence of homeotropic-transient planar-planar; at high bias fields, the liquid crystal transforms to the focal conic state. The homeotropic-transient planar transition is on the order of 1 ms while the homeotropic-focal conic transition is on the order of 100 ms. Large hysteresis is observed in the transitions between the homeotropic and the focal conic state. Based on the rapid homeotropic-transient planar transition and the hysteresis effect in the focal conic-homeotropic transition, we have designed a drive scheme which can address bistable reflective cholesteric displays at the speed of one Line per millisecond.