A Flexure Mode Piezoelectric Transducer for Driving the Ossicular Chain of Research Animals

Abstract

This paper describes the development rationale and some of the operating characteristics of a piezoelectric transducer for ossicular chain activation. By utilizing a very thin, bimorph-type, flexure-mode piezoelectric transducer in a cantilevered configuration, relatively large displacements can be generated by very low activating voltages, typically less than 1 V to produce displacements corresponding to normal communication levels. Measurements of transducer activating voltage necessary to produce various levels of round-window cochlear microphonic (CM) are compared with tympanic-membrane sound-pressure levels necessary to produce equal round-window CM in response to pure-tone waveforms. Umbo displacements produced by the transducer are compared with umbo displacements produced by pure-tone sound fields down to displacement levels less than 10 Å, through the medium of constant round-window CM in guinea pigs. Other investigations have concerned the ability of the transducer to deliver complex signals to the ossicular chain.