Switchable liquid crystal devices

摘要

A switchable liquid crystal device, for instance for use as a reflective display, includes a cell containing a helical polymer network and a nematic liquid crystal. Electrodes are provided for applying a field across the cell so as to switch between different optical states. In a reflective state, the cell reflects incident light within a waveband which is relatively insensitive to temperature variations. The device is formed by filling the cell with the liquid crystal and polymer precursor material and then cross-linking or polymerising, for instance by photopolymerisation, the precursor material to form the helical polymer network.