| 摘要 |
A pair of appropriately oriented 90 DEG twisted nematic cells 6, 7 each incorporating a guest dye and each having internal electrodes 8, 14, 9, 15 that overlap in part are placed between appropriately oriented crossed polarisers 12, 13 to provide a display device that appears black in transmission when unenergised and can be energised to provide one of two alternative legends in black displayed against contrasting backgrounds of different colour. If one of these background colours is white one of the guest dyes is omitted, An appropriately oriented coloured polariser located between the cells may be substituted for a guest dye. |
