Fringing Field Effect Of The Liquid-Crystal-On-Silicon Devices

The fringing field has an important effect on the contrast ratio of liquid-crystal-on-silicon (LCOS) display devices. Computer simulation results of five commonly employed LC operating modes are compared: mixed-mode twisted nematic (MTN) cell, 45 twisted nematic cell, vertical alignment (VA) cell, film-compensated homogeneous cell, and fringe-field switching cell. The slope of the pixel electrodes is found to make an important contribution to the brightness and contrast ratio of each mode. Simulation results indicate that the VA mode has the best contrast ratio when all the pixels are on and off. However, the MTN cell shows the smallest fringing field effect when alternating pixels are switched on and off