Non-Ge optics and low-cost electronics designs for LIR imagers

Evan Zhang; Vivian W. Song; James S. Zhang; Cunwu Yang

doi:10.1117/12.469690

23 January 2003 Non-Ge optics and low-cost electronics designs for LIR imagers

Evan Zhang, Vivian W. Song, James S. Zhang, Cunwu Yang

Proceedings Volume 4820, Infrared Technology and Applications XXVIII; (2003) https://doi.org/10.1117/12.469690
Event: International Symposium on Optical Science and Technology, 2002, Seattle, WA, United States

Abstract

Until today, almost all objective lenses and windows of LIR imagers use crystal Germanium (Ge) as the optical material. Germanium is heavy, expensive and very sensitive to the environmental temperature change. When the temperature rises above 120° C, the lens becomes opaque. It is necessary to overcome these shortcomings. Using the analytic universal skew ray tracing formula and the automatic optical system design software developed by us, we successfully designed a 150mm/F1 objective lens using Ge and non-Ge materials for the LIR imager of the missile seeker and airborne surveillance. We also successfully designed a 25mm/F1 objective lens with large FOV of 30°x40° using only non-Ge materials for the LIR imager of the helmet mounted search and rescue system. Good image quality is obtained. The cost is less than half of the Ge lens and the high temperature resistance is much better. In order to increase the S/N ratio 4 times for the low-sensitivity UFPA, an immersed Ge lens for the UFPA is also successfully designed. Currently, most of UFPAs use high-cost Digital Signal Processing (DSP) module. The LIR imager needs at least two circuit boards. We present a design that uses low-cost Altera processor and the imager only needs one board without Thermal Electrical Cooler (TEC). Therefore, three "AA" batteries can operate the imager for more than 4 hours. By inserting data between pixels and enhance the contrast, the image from the 120x120/50μ UFPA is even better than the image from the 240x320/50μ array. This gives us an opportunity to reduce the imager cost to 2/3 of the larger format without degrading the image quality. These innovative researches give us a chance to build a small, lightweight, inexpensive, and good image quality LIR imager for homeland security and many other military and commercial applications. Two patents were pending and one was granted.

Citation Download Citation

Evan Zhang, Vivian W. Song, James S. Zhang, and Cunwu Yang "Non-Ge optics and low-cost electronics designs for LIR imagers", Proc. SPIE 4820, Infrared Technology and Applications XXVIII, (23 January 2003); https://doi.org/10.1117/12.469690

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