Title: Micro audio directional system for portable multimedia devices

Authors: Xuesheng Li; Limei Xu; Leon Xu

Addresses: Institute of Astronautics and Aeronautics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China. ' Institute of Astronautics and Aeronautics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, China. ' Nokia Research Center (Beijing), No. 5, Dong Huan Zhong Lu, BDA, Beijing, 100176, China

Abstract: A micro audio directional system for portable multimedia devices is investigated as a novel loudspeaker which can provide privacy listening service. It can generates audible sound with high directivity in a narrow conical beam by an ultrasonic transducer array. A piezoelectric micromachined ultrasonic transducers (pMUT) array and a PZT ceramic wafer transducers array are presented respectively. The testing results of impedance, frequency response and sound pressure level characteristics are described and compared. A prototype with PZT ceramic wafer transducers array is constructed for mobile phone usage and its acoustic characteristics are measured. The experiment results indicate the feasibility of utilising the audio directional system with low power consumption and micro size in portable multimedia devices as well as in mobile phone.

Keywords: micro audio directional systems; private listening services; PZT ceramic wafers; piezoelectric transducers; micromachined transducers; transducer arrays; portable devices; multimedia devices; ultrasonic transducers; mobile phones; cell phones; acoustics; power consumption.

DOI: 10.1504/IJMA.2012.049399

International Journal of Mechatronics and Automation, 2012 Vol.2 No.3, pp.178 - 184

Received: 30 Mar 2012
Accepted: 13 Jul 2012

Published online: 02 Oct 2012 *

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