Evaluation of an nMOS VLSI array for an adaptive liquid-crystal spatial light modulator

An nMOS-addressed liquid-crystal array has been designed, primarily for use as a spatial light modulator in the Fourier plane of a coherent optical processor. Specification of the performance of such filters in an ideal system is considered briefly, and a description is given of the operating parameters of our prototype device. Details are presented of the VLSI design for the integrated circuit, which consists of a square array of 16 ¿¿ 16 pixels covering a total active area of 3.2 ¿¿ 3.2 mm2 on a silicon chip. An outline is also given of a simple interface circuit, built from discrete components, which allows the liquid-crystal filter to be controlled through the 8-bit port of a microcomputer. When illuminated with noncoherent light, the device acts as a liquid crystal display with `on-board¿¿ memory.