Fabrication and characterization of an infrared-absorption-type CO2 gas sensor using a PLZT optical shutter

In aiming to improve the performance and reliability of infrared absorption type CO2 gas sensors, a high-sensitivity bulk thin-plate-type pyroelectric infrared sensor and an infrared-absorption-type CO2 gas sensor using electrooptic chopping have been fabricated and their performance studied. In a gas sensor combining a conventional bulk-type pyroelectric sensor and a mechanical chopper, a detection sensitivity of 0.029 mV/ppm for a unit concentration is obtained. On the other hand, if the bulk thin-plate-type pyroelectric sensor is used, the sensitivity is 0.12 mV/ppm, which is four times as great. When a bulk thin-plate-type pyroelectric sensor and a PLZT optical shutter are combined, the sensitivity is 0.026 mV/ppm. Hence, a highly reliable CO2 sensor that eliminates the mechanical chopper with a performance equivalent to that of the conventional type can be realized. © 1999 Scripta Technica, Electron Comm Jpn Pt 2, 82(4): 1–8, 1999