Microscopic texture and grey scale generation in anti-ferroelectric liquid crystals

Polarized stroboscopic microscopy shows that in anti-ferroelectric liquid crystal devices a uniform increase in light transmission takes place during the application of a short voltage pulse of sufficient amplitude. When this pulse is followed by a lower voltage, the transmission fades in two steps: in the first a fast uniform decay is observed and is accompanied by stripes that rapidly appear out of the background; then a slower striped domain growth process takes place. On the other hand, when a device is allowed to relax from the ferroelectric state, only a domain growth process is observed. We discuss the physical mechanisms involved and the effects of writing and holding voltages on grey levels and their implications for display applications.