Sound Generator Structure for Low-Elastic Electroactive Polymer

Introduction

Major innovations in advanced multichannel audio systems have made it possible to put 22.2 multichannel sound system and wave field synthesis to practical use. Such systems require many loudspeakers that have never been used in homes up to now. The requirement might become a major barrier to the popularization of multichannel audio systems; thus, the development of loudspeakers that may not affect our living space is strongly required.

Electroactive polymer (EAP) is one of the up-to-date actuators that have brought distinct applications from the conventional actuators. It’s prominent features are high strain and large transformation under voltage application, which are much larger than those of common pizoelectric materials. Consequently, many studies have been conducted on EAPs and applications to acoustic transducers have also been explored.

The purpose of this study is to use a simple structure to capture large transformation of the low elastic EAP for sound generation. In this paper, we propose a sound generator structure that provides a mechanical bias with the EAP without an external device and efficiently uses transformation of the EAP to drive the diaphragm. Measurements of the prototype sound generator are conducted and it’s acoustic characteristics are presented.