Precision piezoelectric acoustic position detector

Cheng Liang Sun, Kwok Ho Lam, J. Wang, H. L.W. Chan, X. Z. Zhao, C. L. Choy

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)


A piezoelectric acoustic position detector has been fabricated using a piezoelectric bimorph ring and an acoustic sensor. The disk type piezoelectric bimorph with a center-opening and the acoustic sensor are placed at each end of a small plastic cylindrical cavity and act as the driving element and the detecting element, respectively. When the driving element vibrates at the cavity's resonance frequency, the air filled plastic cavity will be excited into a resonance state. The resonance frequency can be estimated by using a Helmholtz resonator theory. When an object obstructs the sound beam, the acoustic field would be changed. This thus leads to a variation in the state of the sound resonance. A lock-in amplifier is used to monitor the output voltage and phase change of the acoustic sensor. The experimental results show that the position detector has a linear phase change of 0.017° μm-1and a linear voltage change of 51.2 μV/μm to small displacement along the acoustic radiation direction.
Original languageEnglish
Pages (from-to)290-295
Number of pages6
JournalSensors and Actuators, A: Physical
Issue number2
Publication statusPublished - 19 Apr 2006


  • Acoustic field
  • Acoustic resonance cavity
  • Helmholtz resonator
  • Position detector

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Instrumentation
  • Condensed Matter Physics
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Electrical and Electronic Engineering


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