Ferroelectric liquid crystal electro-optical device having half-select voltage to maximize contrast,申请号US19870054739-传众专利搜索

Ferroelectric liquid crystal electro-optical device having half-select voltage to maximize contrast

申请公布号：US4762400(A)

申请号：US19870054739

申请日期：1987.05.27

申请公布日期：1988.08.09

申请人：

SEIKO INSTRUMENTS INC.

发明人：SHIMODA, SADASHI;HARADA, TAKAMASA;TAGUCHI, MASAAKI;ITO, KOKICHI

分类号：G02F1/133;G09G3/36;(IPC1-7):G02F1/13

主分类号：G02F1/133

摘要：A ferroelectric liquid crystal electro-optical device driven in time-sharing comprising; a ferroelectric liquid crystal layer having bi-stable alignment characteristics, means for converting the bi-stable alignment state to optical ON state or optical OFF state, a matrix electrode and means for driving the liquid crystal layer by applying voltages to the liquid crystal layer through the matrix electrode. A voltage sufficient to change a stable alignment state of the ferro-electric liquid crystal molecular is applied to a selected pixel, a voltage insufficient to change a stable alignment state is applied to a non-selected pixel and an AC voltage for holding a stable alignment state is applied to a half-selected pixel. A bias value, which is the ratio of the amplitude of the voltage applied to the selected pixel to the amplitude of the AC voltage applied to the half-selected pixel, is set near the maximum value of B satisfying the following formula B/(B-2)>/=Vsat/Vth, wherein Vsat is the minimum value of voltage which enables to change a stable alignment state to the other state and Vth is the maximum value of voltage which enables to hold the stable alignment state.