Analytical electrical model for a Si liquid crystal light valve.
An approximate analytical model has been developed which allows the voltage characteristics of the liquid crystal layer of a silicon liquid crystal light valve to be determined once the photocurrent level and device parameters have been specified. This model significantly decreases the computation time compared to current numerical techniques.
Liquid crystal light valves: A review of recent studies
Recent studies of the dynamics of nematic liquid crystals as well as in modeling of the photoactivated and CCD-addressed liquid crystal light valves are described. Recent developments in the visible to IR dynamic image converter are reviewed.
Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications
A visible-to-infrared image converter based on the Hughes 2-in. liquid-crystal light valve is under development at Hughes Research Laboratories. The system is designed to operate in the 2- to 5-μm and 8- to 12-μm spectral ranges. The device consists of an IR-visible transparent input substrate electrode; an IR-transparent, visible-sensitive photoconductor (CdS); and a thin layer of liquid crystal acting as the light modulator medium. The readout window is transparent in the IR range used. The required IR dynamic scenery, generated for convenience in a visible form (e.g., on a CRT), is projected onto the input window, thus activating the photoconductor. This spatial voltage pattern of the required image is transferred to the liquid crystal, thus converting the image to a birefringent spatial modulation. The polarized infrared readout beam projected through the light valve is modulated as it passes through the liquid crystal. The latter operates in the 90° twisted nematic mode. The required IR scenery is then formed as the polarization-modulated IR beam passes a 90° cross-polarizer. The device offers the advantages of (1) maximum flexibility in presenting versatile dynamic IR sceneries and (2) high resolution and contrast. Good performance was demonstrated by a device operating in the 2- to 5-μm range. The proposed approach strongly benefits from the technology that has been developed for the visible-to-visible liquid-crystal light valve over the last few years.