Hysteresis loops of ferroelectric liquid crystal displays

Abstract

The director orientation of the ferroelectric liquid crystal molecules within a surface-stabilized display is considered as being uniform. Under this simplifying assumption, it is possible to calculate analytically the polarization p of the display under a sinusoidal excitation v. It turns out that the polarization versus voltage curve p(v) has a strongly frequency dependent hysteresis loop. E.g. the width of the hysteresis loop (i.e. the coercive voltage W) increases with increasing frequency f like f^1/2, over a large range of frequencies. Experimental results for ZLI 3654, in the frequency range from 10 Hz to 100 kHz, confirm the usefulness of the simple model.