High Sensitive Acoustic Sensor using PMN-PT Piezoelectric Cantilever Array
S. Hur, S.Q. Lee
Korea Institute of Machnery & Materials, KR
Keywords: acoustic sensor, PMN-PT, piezoelectric, cantilever
Abstract:In this paper, we have studied about a high sensitive acoustic sensor using PMN-PT single-crystal piezoelectric cantilever array as an alternative of conventional acoustic sensor. The PMN-PT material has been shown to possess piezoelectric coefficients and electro-mechanical coupling responses significantly larger than conventional ceramics. We have fabricated piezoelectric PMN-PT cantilever array which has the cantilever size of the width of 200 um and the thickness of 10um. The length of cantilever was adjusted with a parameter of resonance frequency. Resonance frequency of PMN-PT cantilevers was measured with laser interferometer and charge sensitivity was measured with charge measuring device. PMN-PT cantilever array was exposed with sound pressure of specific frequency corresponding to resonance frequency. The sensitivity and directivity of sound pressure was measured. The measured sensitivities of acoustic sensor at the resonant frequency of 1.2 kHz and 11.5 kHz are 40.0 and 40.1 dB/Pa, respectively. The fabricated acoustic sensor shows a flat frequency response in the audio frequency range. The experimental results show that the PMN-PT cantilever array exhibits high sensitivity. This implies that the single crystal PMN-PT cantilever array has a potential candidate as high sensitivity acoustic sensor.