A SILICON RESONANT SENSOR STRUCTURE FOR CORIOLIS MASS-FLOW MEASUREMENTS

We present the first mass-how sensor in silicon, based on the Coriolis -force principle. The sensor consists of a double-loop tube resonator structure with a size of only 9 x 18 x 1 mm. The tube structure is exc ited electrostatically into a resonance-bending or torsion vibration m ode. A liquid mass how passing through the tube induces a Coriolis for ce, resulting in a twisting angular motion phase-shifted and perpendic ular to the excitation. The excitation and Coriolis-induced angular mo tion are detected optically. The amplitude of the induced angular moti on is linearly proportional to the mass flow and, thus, a measure ther eof. The sensor can be used for measurement of fluid density since the resonance frequency of the sensor is a function of the fluid density. The measurements show the device to be a true mass-flow sensor with d irection sensitivity and high linearity in the investigated how range of as low as 0-0.5 g/s in either direction. A sensitivity of 2.95 (mV/ V)(g/s) and standard deviation for the measured values of 0.042 mV/V a re demonstrated. [207]