Fast-switching liquid-crystal-on-silicon microdisplay with framebuffer pixels and surface-mode optically compensated birefringence

A 64×32 liquid-crystal-on-silicon (LCOS) backplane with a novel framebuffer pixel array has been designed and fabricated using the AMI Semiconductor 0.5-µm double-poly triple-metal CMOS process. The pixel circuit described herein increases the brightness significantly without sacrificing image contrast ratio. Characteristics of various liquid-crystal modes applicable to field sequential color displays have been investigated. The LCOS microdisplay, employing an optimized optically compensated birefringence mode, demonstrates fast response times (OFF=0.3 ms, ON=1.2 ms) enabling a frame rate of 720 Hz, with a potentially high contrast ratio of up to 1600:1.