Grey levels in FLC based on static threshold

Analog grey levels in FLC have been investigated based on the dependence of the critical V tau product on the surface anchoring constant gamma. This d ependence is weak and consequently analog grey levels are difficult to cont rol. We therefore analysed the possibilities of grey levels based on the st atic threshold, which is proportional to gamma. We find that grey levels ar e indeed possible but with two drawbacks: the switching time is large, and there is a rather strong pretransitional effect. Both drawbacks can be over come by active matrix addressing.