A Self-Calibration Method of Microbolometer With Vacuum Package

Abstract

Microbolometer is often packaged in a vacuum atmosphere of < 1 Pa to improve its response. The internal pressure of vacuum package always drifts over time. This will lead to the response degradation of microbolometer. To maintain excellent performance and improve device lifetime, a self-calibration method of microbolometer with vacuum package is presented. This method uses the relative change rate obtained by self-heating response to calibrate the IR response according to the linear dependence of self-heating response and IR response at different pressures. Its validity is verified using a microbolometer with series diodes. The degraded IR voltage responses can be corrected to the normal value when the internal pressure increases from 1 Pa to 500 Pa. Furthermore, the relative standard of calibration deviation is small when the internal pressure is no more than 50 Pa.