Kenji Murase

Parallel-Scan Thermal Imager With A Thermoelectrically Cooled Multielement Detector

This paper describes the design and performance of a low-cost parallel-scan thermal imager. The sensor, with a 16-element photoconductive HgCdTe detector, employs a thermoelectric cooler that has the advantages of low life cycle costs, relatively light weight, and high reliability. The scanner is a rotating polygonal mirror with different degrees of tilt on the facet faces, which allows buildup of the square format in object space. This type of scanner has a simple structure and is suited for high-speed operation. In order to lower production costs, an aluminum polygonal mirror, manufactured by precision single-point diamond turning, has been developed. The system has the following parameters, determined by making a trade-off study among performance, size, and cost: field of view, 14.7° x 14.7°; angular resolution, 2 mrad; aperture of focal optics, 23 mm; frame rate, 20 Hz; resolution, 128 x 128 lines; and NETD, 0.6°C.