FPN Sources in Bolometric Infrared Detectors

Low manufacturing cost and ease of use favor spreading of 2-D bolometric infrared detector arrays over various application domains such as predictive maintenance, medical imaging, automotive industry, and security. The infrared detector´s main figure of merit has long been the noise equivalent temperature difference (NETD), which sets the minimum temperature difference distinguishable from background noise at sensor output. However, while nowadays uncooled detectors have achieved sufficient NETD, fixed pattern noise (FPN) is indeed becoming a crucial figure of merit especially when the focal plane array (FPA) is not regulated by a thermoelectric cooler (TEC). In this paper, we study the various sources of dispersion of infrared bolometric detectors and their respective impact on FPN in the resulting image. We propose an analytical model to identify main sources of nonuniformity, and the confrontation of results with actual measurements leads to the ability of a highly accurate on-chip thermal drift compensation.