π/2 and 5π/2 twisted bistable nematic liquid crystal display

A π/2 and 5π/2 twist bistable nematic liquid crystal cell is optimized in optics by a parameter space approach. The cell possesses good contrast ratio, a preferable dΔn value, a wide viewing angle, and black–white display. Three switching wave forms can be used to switch the cell between π/2 and 5π/2 twist states. Controlling the selection voltage amplitude can provide gray scales for the cell.