Tailoring the performance of flexible electret loudspeakers by varying cell actuator formation

Abstract

We present a design of electret-based soft cell actuators which can improve the performance of flexible electret loudspeakers. Electret loudspeakers have advantages over traditional speakers such being thin, lightweight and flexible. They have potential application to 4C products (e.g. computers, communication, consumer electronics, and cars). Flexible electret loudspeakers are composed of an array of small cell actuators. The first mode of each electret cell actuator greatly affects the low frequency of an electret loudspeaker. To tailor the bandwidth of an electret loudspeaker for different applications, the shape and size of each cell actuator can be varied according to the specific requirements. A finite element analysis (FEA) model was used to simulate a vibration mode. An AVIDTM (advanced vibrometer/interferometer device) system and ESPI (electronic speckle pattern interferometry) system were two non-destructive optical detection tools used to detect vibration and the corresponding vibration mode shape of the electret cell actuators, respectively. Our experimental results verified the simulated results. We showed that finite element analysis (FEA) can be used to design flexible loudspeakers. We can tailor the sound characteristics of an electret loudspeaker by varying the size and shape of cell actuators such that flexible electret loudspeaker performance can be dramatically improved.