An In-Situ Self-Test Method for Measuring Absorptivity of Film-Type Uncooled Infrared Detectors

Uncooled infrared (IR) detectors have a wide range of applications in consumer and industry. They realize the conversion from IR radiation to thermal heat through an absorber. Absorptivity is the main evaluation parameter of this radiation conversion efficiency. Measuring the absorptivity is of great importance in evaluating detectors' performance. In this work, according to Kirchhoff's law of thermal radiation, the absorptivity in a whole IR spectral range is extracted from relation of thermal conductance to absorber temperature only utilizing Joule effect of detectors. The absorptivity in a certain IR spectral range is obtained with the established relationship of absorptivity between different IR spectral ranges. The experiment applying this method is carried out using a thermopile detector integrated with a N-polysilicon heater. And for verification and comparison, the measurement with blackbody optical system and the theoretical calculation are also performed. All results are consistent well with each other, which verifies the validity of the proposed method. This method has the advantage of no sample preparation requirement and is an in-situ self-test measurement. [2021-0185]