Optimization of reflective bistable twisted nematic displays with retardation compensation

摘要

The contrast ratios of reflective bistable twisted nematic liquid crystal displays with a rear quarter-wave film are optimized by means of a parameter space approach. By plotting the contrast ratio as a function of the twist angle and thickness-birefringence product (d△n) of the display, the regions where the displays show the best contrast ratio are clearly shown. Both the absolute reflectance and the wavelength dispersion of two bistable twisted states are investigated. It is confirmed that superhigh contrast ratio (infinite in principle), reflectance about 95 with polarized-light input, a large d△n value (0.63 μm), and low dispersion are possible for such reflective bistable liquid crystal display.