Qualitative and quantitative substance discrimination using a CMOS compatible non-specific NDIR microarray

A non-specific non dispersive infrared (NDIR) micro-optical gas detection system is presented. The system is based on a monolithic filter microarray (up to 16 non substance oriented elements) that is attached by flip-chip onto a matching microarray of thermopiles, configuring a compact CMOS compatible optical detector. The system aims to combine the stability of infrared optical devices and the versatility of electronic-nose approaches. The transmission spectra of the filters, multi-peaked and of broad band nature, are not oriented to any specific substance detection, and multivariate regression techniques are used to predict gas type and concentrations from the voltage pattern generated by the thermopile array. The ability of the system for substance discrimination has been proved by means of qualitative volatile identification (ethanol, isopropanol and acetone) and quantitative tests have been performed with CH4 and CO2 mixtures.