A liquid crystal device is described that comprises a layer of liquid crystal material contained between a first cell wall and a second cell wall. The layer of liquid crystal material being switchable between at least a first state and a second state, said first state and said second state having sufficiently...http://www.google.com.hk/patents/US7956980?utm_source=gb-gplus-share專利 US7956980 - Liquid crystal device with bi- or multistable alignment gratings
