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http://dx.doi.org/10.4313/JKEM.2008.21.6.556

Characteristics of Piezoelectric Microspeakers according to the Material Properties  

Jeong, Kyong-Shik (충주대학교 기계공학과)
Cho, Hee-Chan (충주대학교 기계공학과)
Yi, Seung-Hwan (충주대학교 기계공학과/친환경에너지 부품소재센터)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.21, no.6, 2008 , pp. 556-561 More about this Journal
Abstract
This paper reports the characteristics of piezoelectric microspeakers that are audible in open air with high quality piezoelectric AlN thin film according to the materials properties. When we use a tensile-stressed silicon nitride diaphragm as a supporting layer, the Sound Pressure Level (SPL) is relatively small and constant at low frequency region and shows about 70 dB at 10 kHz. However, in case of a compressively stressed composite diaphragm, the SPL of the fabricated microspeakers shows higher output pressure than those of a tensile-stressed diaphragm. It produces more than 66 dB from 100 Hz to 15 kHz and the highest SPL is about 100 dB at 9.3 kHz with $20V_{peak-to-peak}$, sinusoidal input biases and at 10 mm distances from the fabricated microspeakers to the reference microphone. From the experimental results, it is superior to have a compressively composite diaphragm in order to produce a high SPL in piezoelectric microspeaker.
Keywords
Piezoelectric microspeaker; Sound pressure level; Composite residual stress; AlN thin film;
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Times Cited By KSCI : 1  (Citation Analysis)
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