Uncooled infrared focal-plane array offers low-cost thermal imagers

Expanded military and commercial applications of thermal imaging are seen by Amber (Goleta, CA) as a result of its fabrication of an uncooled infrared (IR) focal-plane array based on microbolometer technology developed by Honeywell (Bloomington, MN). Amber integrated this array with a proprietary CMOS silicon-readout integrated circuit. A 320 × 240 bolometer focal-plane array less than an inch square forms the uncooled sensor, which operates in the 8 × 12-µm wavelength region. The company claims the images obtained are comparable to ones taken with its cooled, InSb-based Radiance 1 camera.

Previous uncooled IR imaging based on ferroelectric technology required mechanical choppers to extract and stabilize an image signal from noise. Also a source of audible noise, choppers need to operate constantly and increase system complexity. Ferroelectric technology can achieve about 0.15°C–0.20°C noise-equivalent temperature difference (NETD), which is a standard measurement describing the minimum change of temperature that can be sensed in a scene being viewed. Amber says its microbolometer based array has a NETD of 0.1°C.