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Electronics and Telecommunications Research Institute (한국전자통신연구원)
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High Performance Piezoelectric Microspeakers and Thin Speaker Array System

  • Kim, Hye-Jin (Convergence Components & Materials Research Laboratory, ETRI) ;
  • Koo, Kun-Mo (Department of Mechatronics, Gwangju Institute of Science and Technology) ;
  • Lee, Sung-Q (Convergence Components & Materials Research Laboratory, ETRI) ;
  • Park, Kang-Ho (Convergence Components & Materials Research Laboratory, ETRI) ;
  • Kim, Jong-Dae (Convergence Components & Materials Research Laboratory, ETRI)
  • Received : 2009.04.28
  • Accepted : 2009.10.19
  • Published : 2009.12.31
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Abstract

This paper reports on an improved piezoelectric microspeaker with a high sound pressure level of 90 dB, a total harmonic distortion of less than 15%, and coherence higher than 0.9. The fabricated Pb(Zr,Ti)$O_3$ (PZT) microspeakers have a thickness of only 1 mm including the speaker frame and an active area of 18 mm${\times}$20 mm. To achieve higher sound pressure and lower distortion, the PZT piezoelectric microspeaker has a well-designed speaker frame and a piezoelectric diaphragm consisting of a tilted PZT membrane and silicone buffer layer. From the simulation and measurement results, we confirmed that the silicon buffer layer can lower the first resonant frequency, which enhances the microspeaker's sound pressure at a low frequency range and can also reduce useless distortion generated by the harmonics. The fabricated PZT piezoelectric microspeakers are implemented on a multichannel speaker array system for personal acoustical space generation. The output sound pressure at a 30 cm distance away from the center of the speaker line array is 15 dB higher than the sound pressure at the neighboring region 30 degrees from the vertical axis.

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References

  1. J. Wang et al., "Polymer Deformable Mirror for Optical Auto Focusing," ETRI J., vol. 29, no. 6, Dec. 2007, pp. 817-819. https://doi.org/10.4218/etrij.07.0207.0107
  2. D. Kim, J. Yeo, and J. Choi, "Compact Spatial Triple-Band-Stop Filter for Cellular /PCS/IMT-2000 Systems," ETRI J., vol. 30, no. 5, Oct. 2008, pp. 735-737. https://doi.org/10.4218/etrij.08.0208.0160
  3. C.S. Lee et al., "An Approach to Durable Poly (vinylidene fluoride) Thin Film Loudspeaker," J. Mater. Research, vol. 18, Dec. 2003, pp. 2904-2911. https://doi.org/10.1557/JMR.2003.0405
  4. T. Horikawa and K. Kobayashi, "Application of Ceramic Piezoelectric Device to Audio Speaker," Proc. SICE Annual Conf., 2008, pp. 1-4.
  5. C. Shearwood et al., "Application of Polyimide Membranes to MEMS Technology," Microelectron. Eng., vol. 30, 1996, pp. 547-550. https://doi.org/10.1016/0167-9317(95)00306-1
  6. H. Kim et al., "Bi-directional Electrostatic Microspeaker with Two Large-Deflection Flexible Membranes Actuated by Sing/Dual Electrodes," Proc. IEEE Sensors, 2005, pp. 89-92.
  7. J.J. Neumann, Jr. and K.J. Gabriel, "CMOS-MEMS Membrane for Audio-Frequency Acoustic Actuation," Sensors and Actuators A: Physical, vol. 95, no. 2, 1 Jan. 2002, pp. 175-182. https://doi.org/10.1016/S0924-4247(01)00728-2
  8. H.J. Kim et al., "A Piezoelectric Microspeaker with a High-Quality PMN-PT Single-Crystal Membrane," J. Kor. Phys. Soc., vol. 54, Feb. 2009, pp. 930-933. https://doi.org/10.3938/jkps.54.930
  9. S.H. Yi and E.S. Kim, "Micromachined Piezoelectric Microspeaker," Jpn. J. Appl. Phys., vol. 44, no. 6A, 2005, pp. 3836-3841. https://doi.org/10.1143/JJAP.44.3836
  10. C.H. Han and E.S. Kim, "Parylene-Diaphragm Piezoelectric Acoustic Transducers," Proc. IEEE Micro Electro Mechanical Systems, IEEE MEMS, 2000, pp. 148-152.
  11. M. Yamada., N. Itsuki, and Y. Kinouchi, "Adaptive Directivity Control of Speaker Array," Int. Conf. Control, Automation, Robotics, and Vision, 2004, vol. 2, pp. 1443-1448.
  12. Y. Wen, J. Yang, and W.S. Gan, "Strategies for an Acoustical-Hotspot Generation," IEICE Trans. Fundam. Electron., Commun. Comput. Sci., vol. E88-A, no. 7, July 2005, pp. 1739-1746. https://doi.org/10.1093/ietfec/e88-a.7.1739
  13. J.W. Choi and Y.H. Kim, "Generation of an Acoustical Bright Zone with an Illuminated Region Using Multiple Sources," J. Acoust. Soc. Am., vol. 111, 2002. pp. 1695-1700. https://doi.org/10.1121/1.1456926
  14. F. Xu, F. Chu, and S.T. McKinstry, "Longitudinal Piezoelectric Coefficient Measurement for Bulk Ceramics and Thin Films Using Pneumatic Pressure Rig," J. Appl. Phys., vol. 86, 1999. pp. 588-594. https://doi.org/10.1063/1.370771
  15. D.-G. Kim et al., "Evaluation Method of Longitudinal and Transverse Piezoelectric d-Coefficients for Thin Films," Integr. Ferroelectr., vol. 35, 2001. pp. 299-312.

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