ANALYSIS OF CHARGE-CONTROLLED GRAY-SCALE IN FERROELECTRIC LIQUID-CRYSTAL OPTICALLY ADDRESSED SPATIAL LIGHT-MODULATOR

In an optically addressed spatial light modulator (OASLM) with ferroel ectric liquid crystal (FLC) and p-i-n photodiode hydrogenated amorphou s Si (a-Si:H), the gray scale characteristics can be explained by the charge-control principle; the amount of charge supplied from the a-Si: H photodiode determines the FLC polarization state between the bistabl e states. We construct an equivalent circuit model based on this princ iple, formulate the operation of the OASLM, and show that this theory agrees with various experimental results. We also show that the OASLM gray scale is realized not by FLC multidomain switching, but by unifor m director rotation between bistable states.