Investigation of thermal electric cooler-less microbolometer infrared imaging

Abstract

The current IR imaging modules developed by BAE SYSTEMS North America use a Thermal Electric Cooler (TEC) to stabilize the Focal Plane Array (FPA). An FPA is an array of microbolometers which are small vanadium oxide elements whose resistances are very sensitive to IR radiation. The ability to run an imaging module without the TEC results in significant reduction in FPA package size, power consumption and module costs. In order to run a module in such a way several variables have to be accounted for. Running the module in TEC-Less mode requires changing the bolometer current as well as adjusting corrective maps in accordance with changes in ambient temperature. This investigation looked at these adjustments in order to determine if TEC-Less imaging was viable for the modules developed at BAE systems. A spatial noise test is used to determine if the TEC-Less images are as good of quality as those taken under normal operation. The results show that TEC-Less imaging over large temperature ranges is possible, and with the adjustments developed in this report, produces images with only slightly higher spatial noise.