Oxygen@ sensor for gas mixt. - measures difference in flow speed in two stream channels etched into wafer substrate by two thermo anemometers

摘要

An oxygen sensor has a gas inlet and outlet connected via gas flow channels. At least one of these channels is divided downstream into two flow channels, one of which is exposed to a magnetic field. The flow difference is measured in the two channels. The flow channels (3-5) are micromechanically produced in a substrate (20), pref. of silicon, pref. using an anisotropic etching technique. The channels are bounded by a covering applied to the substrate. The covering may be of glass or a micromechanically structured silicon plate. ADVANTAGE - Very compact. High sensitivity.