Compact Thermal and System Modeling of Chip-Scale Pyroelectric Infrared Imager

The performance of pyroelectric infrared detectors is directly related to the ability of the sensor material to retain infrared energy (heat) incident from the source and to react fast to changing heat loads. This leads to a complicated, three dimensional, transient thermal models when many detectors are assembled into an infrared focal plane array (IRFPA) for thermal imaging. Adjacent pixels and the underlying substrate conduct heat away from the sensor material and add thermal mass to the system. This paper describes efforts and drawbacks in deriving a system model to capture thermal phenomena in a candidate IRFPA. Of particular interest is the tradeoff between cumbersome finite element models (long solve time, complicated meshes) and a reduced-size RC network circuit model that is simple to solve and integrate with the electrical design but may not capture the full thermal behavior of the system adequately. The thermal models are cast in terms of the operating principles of pyroelectric devices to describe a full electrical-thermal system model that adapts existing literature in the field to the specific system described in this work.