Simulation and experimental study of flexible electret-based loudspeaker vibration modes by electronic speckle pattern interferometry
Journal
Proceedings of SPIE - The International Society for Optical Engineering
Journal Volume
7791
Date Issued
2010
Author(s)
Chen, Y.-C.
Chen, T.-H.
Chien, C.-J.
Chang, W.-C.
Cheng, C.-C.
Ko, W.-C.
Wu, K.-C.
Abstract
Electret-based electrostatic devices have been used in the electro-acoustic field for decades. Recently, the improvement of its charge retention has been of interest for application to the field of smart materials. Hence, the flexible electret-based loudspeaker has become an important research topic for futuristic applications such as 3C (computers, communications and consumer electronics) and smart curtains. The volume velocity and the on-axis sound pressure level (SPL) of an electret loudspeaker are the key parameters of interest. To study the vibration characteristics of an electret diaphragm, a finite element analysis (FEA) was introduced to facilitate the design. To validate the finite element analysis (FEA) model, an out-of plane full-field non-destructive optical detection method which incorporates electronic speckle pattern interferometry (ESPI), was applied to determine the vibration mode shape of thin film. By driving the electret loudspeaker at different frequencies, a corresponding vibration mode of interest was detected with the ESPI set-up. Both the simulations and the experimental results obtained on the measurement platform are detailed in this paper.
Type
conference paper