Design of the Piezoelectric Transducer for the Round Window Drive Implantable Hearing Aids

In this paper, we describe the design and implement of a piezoelectric transducer for round window drive implantable hearing aids. A proposed piezoelectric transducer is small enough to be easily implantable to RW niche and has excellent low-frequency output characteristics. It consists of a titanium case, a metal ring, a vibration membrane, a metal supporter, a piezoelectric material, a ceramic tip and a bellows. Considering the anatomical structure of the RW niche, the dimension of the designed piezoelectric transducer was a 1.75 mm diameter and 2.5 mm length. The structure of the vibration membrane that determines the frequency characteristics of the proposed transducer was derived through the mechanical vibration analysis. The piezoelectric transducer was fabricated based on the simulation results and the vibration characteristics was measured using the laser Doppler vibrometer.