Research on the Electrical-Thermal-Acoustic Conversion Behavior of Thermoacoustic Speakers Based on Multilayer Graphene Film

Abstract

In this work, a porous multilayer graphene film is designed as thermoacoustic speaker using laser scribing technology and a theoretical model based on thermally induced EDFs (Energy Density Fluctuations) is proposed to study its electrical-thermal-acoustic conversion behavior. According to this model, the relationship of the heat energy Q <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">air</sub> with the input power is obtained, and the relationship of the sound pressure with the measuring distance, the frequency and the input power is obtained. The measurement of temperature distribution shows that the maximum temperature of graphene film increases linearly with the input power. The measurement of sound pressure shows that SPL (Sound Pressure Level) decreases with the measuring distance. SPL has a rapid growth in low frequency while slow growth in high frequency. SPL has a logarithmic relationship with the input power. The measured results have a good agreement with the theoretical results. The theoretical model based on EDFs has certain reference value for further research on thermoacoustic speakers. This porous multilayer graphene film has the characteristics of one-step fabrication, no mechanical vibration, simple structure and high performance. It could open broad applications in biology, medicine, wearable electronics and other fields.