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Proceedings Paper

A novel approach to pyroelectric imaging
Author(s): Charles M. Hanson
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Paper Abstract

Pyroelectric imagers lost the competition against bolometers for two reasons: 1) the need for a chopper, and 2) the inability to effectively reduce pixel size. The advantage it had in the competition was extremely low spatial noise, which resulted from its inherent AC coupling, which is what necessitated the chopper. The need for a chopped signal was also at least partly responsible for the difficulty in reducing pixel size, because chopping reduces the time the detector is exposed to the scene. Past concepts for chopper-less pyroelectric detectors have introduced spatial noise at least as problematic as that of bolometers, and they also eliminated the 1/f noise suppression afforded by AC coupling. A patent5 issued in 1996 addressed these problems by using electrostatically-driven micromechanical movement to touch an active pyroelectric pixel to the substrate, thereby resetting the pixel temperature to that of the substrate. While this promised significant improvement, and while it was demonstrated in mechanical test pixels, it was never attempted in any kind of operational device. That concept has now been further developed in theory, and it has been dramatically improved in terms of potential performance. By increasing the reset rate and recursively averaging the resulting signals, the signal is substantially increased because the temperature rise never experiences the thermal roll-off of longer exposures. Noise, which is dominated by far by 1/f noise, is also suppressed by the increased rate of correlated double sampling.

Paper Details

Date Published: 14 May 2019
PDF: 18 pages
Proc. SPIE 11002, Infrared Technology and Applications XLV, 110021N (14 May 2019); doi: 10.1117/12.2519553
Show Author Affiliations
Charles M. Hanson, SenseIR Solutions, LLC (United States)

Published in SPIE Proceedings Vol. 11002:
Infrared Technology and Applications XLV
Bjørn F. Andresen; Gabor F. Fulop; Charles M. Hanson, Editor(s)

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