Fast Liquid Crystal Technology and Its Applications

Fast response liquid crystal display can improve motion picture quality and power efficiency. One of the most important applications is field-sequential-color display. The maximum relaxation time of such liquid crystal device must be less than a few milliseconds (i.e. <3ms).;In this thesis, three different approaches, which are liquid crystal configuration, alignment layer and driving method, are explored in order to enhance the optical response of the liquid crystal device.;A liquid crystal configuration called Stressed Splay Twist (SST) mode is investigated. It exhibits strong and fast optical bounce due to back-flow effect. It is also found that such fast optical transient effect, i.e. <1.5ms, can be controlled by the two voltages driving method effectively. A SST mode field-sequential-color display with QVGA resolution is fabricated.;In order to further improve the electro-optical properties of the SST mode, a stacked alignment layer is proposed as well. It is composed of 2 alignment layers which have different preferred alignment directions. Such alignment configuration is capable of generating multiple pretilt angles or azimuth angles on the same substrate. By using such alignment layers, the relaxation path of the SST mode is modified so that two voltages driving method can be avoided.;Finally, a modified passive matrix display driving scheme is proposed. The typical response time of the passive matrix liquid crystal device is about 50ms to 200ms. The Alt-Pleshko driving method is modified. The response time of the passive matrix displays is promoted to less than <5ms. Such effect is demonstrated by fabricating a passive matrix driven field-sequential-color device.