An ultra-small integrated CO2 infrared gas sensor for wearable end-tidal CO2 monitoring
Liyang Feng, Yanxiang Liu, Yi Wang, Hong Zhou, Ming C. Wu, Tie Li
Abstract
Human physiological metabolic status can be obtained by monitoring exhaled CO 2 concentration, but current CO 2 sensors have disadvantages such as large size, high power consumption, and slow response time, which limit their application in wearable devices and portable instruments. In this article, we report a small size, good performance, and large range CO 2 infrared gas sensor that integrates a high emissivity MEMS emitter chip, a high detectivity thermopile chip, and a high coupling efficiency optical chamber to achieve high efficiency optical-thermal-electrical conversion. Compared with typical commercial sensors, the size of the sensor can be reduced by approximately 80% to only 10 mm × 10 mm × 6.5 mm, with the advantages of low power consumption and fast response speed. Further, a monitoring system for end-tidal CO 2 concentration installed on a mask was developed using this sensor, and good results were achieved.