ACHROMATIC COMPOUND RETARDER

摘要

This invention provides achromatic compound retarders, achromatic polarization switches, and achromatic shutters using the liquid crystal compound retarders. It further provides achromatic variable retardance smectic and nematic liquid crystal retarders. The achromatic compound retarders according to the invention are used to create achromatic inverters for display applications. The display comprises one or more retarders (320a-320n) having in-plane retardance and in-plane orientation, at least one of the retarders being an actively controlled liquid crystal retarder, and a ferroelectric liquid crystal display (370), wherein the one or more retarders work in combination with the ferroelectric liquid crystal display (370) to provide four states of brightness.