Patent ID: 8228301

Claim:
A multicolor writing tablet comprising: electrically conductive layers; at least two active layers stacked over each other, each disposed in a gap between adjacent electrically conductive layers, said active layers including bistable cholesteric liquid crystal material; an outer layer of flexible transparent material forming a writing surface; a light absorbing back layer adapted to absorb light passing through said active layers; wherein said active layers are adapted to enable writing pressure applied to said writing surface to reduce thickness of said gaps to form reduced gap regions; electronic circuitry for applying erasing and writing voltages to said electrically conductive layers for each of said active layers; wherein said erasing voltage is a voltage that enables said liquid crystal material of said active layers to be placed in a planar texture reflecting light of a predetermined color or a different erasing voltage that enables said liquid crystal material of said active layers to be placed in an essentially transparent focal conic texture; and wherein said writing voltage enables writing on said tablet in a color selected from any of said active layers by applying said writing voltage to said electrically conductive layers for a non-selected active layer while applying said writing pressure to said writing surface, enabling said reduced gap region of said non-selected active layer to be in said essentially transparent focal conic texture and by not applying said writing voltage to said electrically conductive layers for a selected active layer while applying said writing pressure to said writing surface, enabling said reduced gap region of said selected active layer to be in said planar texture reflecting light of a predetermined color.