Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications

J. Grinberg; U. Efron; M. J. Little; W. P. Bleha

doi:10.1117/12.958731

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24 June 1980 Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications

J. Grinberg, U. Efron, M. J. Little, W. P. Bleha

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Proceedings Volume 0226, Infrared Imaging Systems Technology; (1980) https://doi.org/10.1117/12.958731
Event: 1980 Technical Symposium East, 1980, Washington, D.C., United States

Abstract

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.

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J. Grinberg, U. Efron, M. J. Little, and W. P. Bleha "Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications", Proc. SPIE 0226, Infrared Imaging Systems Technology, (24 June 1980); https://doi.org/10.1117/12.958731

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