Sensitivity Calibration of a Lead-Zirconate-Titanate (PZT) Thin-Film Intracochlear Microphone

10.6567/IFToMM.14TH.WC.OS19.017

Chu-An Luo；M. Staley；G. Z. Cao；I. Y. Shen

Intracochlear microphones ； Lead-zirconate-titanate ； thin films ； diaphragms ； sensitivity calibration

Proceedings of the 14th IFToMM World Congress

14th-6（2015 / 11 / 11）

25 - 29

英文

An intracochlear microphone is a critical component to enable totally implantable cochlear prostheses. In this study, the intracochlear microphone takes the form of a piezoelectric diaphragm with an area of 0.8 mm by 0.8 mm and a thickness of roughly 2μm. A tuning fork generates a pure-tone sound at 4096 Hz exciting the piezoelectric diaphragm. In the meantime, a laser Doppler vibrometer measures the vibration amplitude at the center of the diaphragm. Also, a charge amplifier measures the charge generated by the piezoelectric diaphragm. The measured sensitivity, defined as the charge-to-displacement ratio, is around 53 pC/μm. For a purpose of comparison, a finite element analysis is conducted to estimate the sensitivity. The simulation shows that the piezoelectric diaphragm has a sensitivity of 30 pC/μm. The close agreement between the numerical and experimental results assures the reliability of the measured sensitivity.