US Patent 11698563 Cholesteric liquid crystal writing device with stylus erase

A liquid crystal writing device is erased by a stylus. The liquid crystal writing device includes a liquid crystal layer including cholesteric liquid crystal material. A user applies pressure to a flexible substrate that changes reflectivity of the cholesteric liquid crystal material to form images on the liquid crystal writing device. The liquid crystal layer is disposed between electrically conductive layers. Writing device terminals are electrically conductive and connected to the electrically conductive layers. The stylus includes stylus electronics adapted to apply an erase voltage or erase voltage waveform to the writing device terminals.