VERFAHREN ZUR ANSTEUERUNG EINER OPTISCHEN FLUESSIGKRISTALLEINRICHTUNG

摘要

A method of during an electro-optical apparatus having a ferro-electric liquid crystal material disposed between two sets of electrodes comprises a first step of applying a first pulse group P1 or P2 to set an electro-optic element firstly in a particular one of its saturated ON or OFF states and then in its other state, a second step of applying a second pulse group P3 or P4 to either set the element in the particular one state or to hold it in its other state and a third step of applying A.C. pulses P5, P6 to hold the element in the desired state and the pulse group P3, P4 includes an equal number of pulses of opposite polarity. The first step whose duration may be lengthened initialises the element in a particular state and reduces the re-writing time of a frame. Gradation or tone variation may be achieved by controlling the amplitude or pulse width of the signals applied to one set of electrodes. Re-writing may be effected in blocks of scanning lines. The apparatus may be used in a display device or a printer. <IMAGE>