| Autor: |
Claus, Richard O., Wade, Janet C., Dockery, George D., Ocheltree, Kenneth B. |
| Zdroj: |
Journal of the Acoustical Society of America; 1982, Vol. 72 Issue S1, pS105-S105, 1p |
| Abstrakt: |
We have previously described the generation of a two-dimensional Gaussian profile ultrasonic field using a piezoelectric transducer with concentric ring electrodes [R. O. Claus and P. S. Zerwekh, J. Acoust. SOC. Am. Suppl. I 71, S12 (1982)]. In this paper, two-dimensional ultrasonic field focusing achieved by a similar transducer is presented. The focusing transducer was constructed using a 7.62-cm-diam crystal quartz disk dimensioned to resonate at 500 kHz. Concentric circular electrodes 1.27 mm wide and separated by 1.27 mm spaces were deposited on one flat surface of the disk and an aluminum foil ground plane and wear plate was attached to the opposite surface using conducting epoxy. By individually varying the time delays between the 300-V 10-ns pulses applied to the electrodes, the location of the focal plane is controlled. In this plane, focus spot half-power diameters of less than two acoustic wavelengths have been obtained. Experimental measurements obtained in a water tank using electrode phasing for both linear geometrical superposition and lens-like focusing are presented and compared with theoretical results. [Work supported in part by NASA and NSF.] [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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