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ZnO Planar Focusing Transducer on Using Fresnel Array

  • Donghai Qiao
  • Shunzhou Li
  • Chenghao Wang
  • Zheying Zhao
Part of the Acoustical Imaging book series (ACIM, volume 20)

Abstract

Fresnel Array can produce focusing of acoustic beam. In this paper we will discuss high frequency Fresnel Arrays which have specially designed electrode structure with ZnO piezoelectric film. The sputtered C-axis oriented piezoelectric film and special electrode structure make longitudinally vibrated transducer arrays. These transducer arrays can generate odd order convergent and divergent beams. But the zero order or even order ones are eliminated. In order to make full use of first order convergent beam we can restrain higher odd order convergent beams by increasing the element width. An important characteristic of Fresnel Array is that its focallength can change linearly with frequency. And hence its focus can quickly scan linearly along the axis. Two kinds of structures, straight and circular strip arrays, are developed to produce line and point focuses, respectively.

We have developed these two planar transducers with center frequency of 400 MHz and bandwidth of about 200 MHz. For the fused quartz their foci can scan along the depth in the range of 8 mm. Their focusing properties were optically observed. And some prepared experiments were also done for NDT and acoustic imaging.

Keywords

Bottom Electrode Order Convergence Transducer Array Fuse Quartz Acoustic Imaging 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. 1.
    Wu Jingyuan, Wang Chenghao et al, Chinese Physics Letters, (1987), p257.Google Scholar
  2. 2.
    Qiao Donghai, Wang Chenghao, et al, Proc. Conference on Ultrasonoelectrics, (1990), p57. (in Chinese).Google Scholar
  3. 3.
    Qiao Donghai, Wang Chenghai, et al, Proc. 14th ICA, C15 -2, Beijing, China, (1992).Google Scholar

Copyright information

© Springer Science+Business Media New York 1993

Authors and Affiliations

  • Donghai Qiao
    • 1
  • Shunzhou Li
    • 1
  • Chenghao Wang
    • 1
  • Zheying Zhao
    • 1
  1. 1.Institute of AcousticsAcademia SinicaBeijingChina

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