摘要 |
A display apparatus includes a cholesteric liquid crystal display device comprising a layer of cholesteric liquid crystal material contained between two substrates, each substrate carrying an electrode layer so that the layer of cholesteric liquid crystal material is interposed between the electrode layers. A piezoelectric element is electrically connected to the electrode layers of the cholesteric liquid crystal display device. The piezoelectric element is capable of being manually activated to generate a drive signal which is sufficient to switch the layer of cholesteric liquid crystal material from the planar state to the focal conic state. The substrates are arranged to allow the layer of cholesteric liquid crystal material to be sheared to switch the layer of cholesteric liquid crystal material from the focal conic state to the planar state by manual compression of the cholesteric liquid crystal display device. Thus the display device can be switched without the need for a battery or other power source. |