Miniaturization of Vibratory Beam Accelerometer by using PZT

Abstract

Electro-magnetically actuated Vibratory Beam Actuator (VBA) with high resolution and stability has been reported. The VBA senses acceleration from the frequency changes of the beams supporting a proof-mass. In this paper, piezoelectric PZT (Pb[Zr, Ti]O3) thin films are employed to actuate the beam and to sense the vibration frequency for miniaturizing the VBA. Well-established fabrication processes including dry-etching PZT are applied to the VBA fabrications. For the acceleration sensing by using VBA, a self-oscillation system, which includes phase-lock-loop (PLL) to maintain resonant oscillations of the beams is constructed. Gravity sensing test, i.e. inclining the sensor, demonstrates a good linearity between applied acceleration and sensing signal. The VBA, promising as a next generation accelerometer, is miniaturized to the area of 4 mm.