24 June 1980 Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications
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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.
© (1980) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Grinberg, J. Grinberg, U. Efron, U. Efron, M. J. Little, M. J. Little, W. P. Bleha, W. P. Bleha, } "Visible-To-Infrared Image Converter For Dynamic Infrared Target Simulation Applications", Proc. SPIE 0226, Infrared Imaging Systems Technology, (24 June 1980); doi: 10.1117/12.958731; https://doi.org/10.1117/12.958731
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