Acoustic characteristics of a flexible sound generator based on thermoacoustic effect

Abstract

A flexible sound generator based on the thermoacoustic effect was proposed for use with thin and flexible devices. The proposed sound generator was composed of three thin films made of aluminum, polyimide, and graphite for effective interaction between acoustic energy and heat. The aluminum functions as an electrode for heat radiation into the air, polyimide as a heat insulator, and graphite as a heat sink. The shape of the electrode was a rectangle. Relationship between sound pressure, applied voltage and temperature change of the electrode was modeled. Radiated sound pressure was analytically described as a function of the input signal's frequency. Experimental measurements were carried out and they showed the validity of the model in terms of radiated sound pressure estimation from the proposed structure with selected materials. Surface vibration was also observed, and it was confirmed that the proposed sound generator is vibration-free. © 2013 Acoustical Society of America.