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Proceedings Paper

Noncontact acousto-optic scanning heterodyne laser vibrometer for measurement of dynamics parameter of hard disK
Author(s): Bryan Kok Ann Ngoi; Krishnan Venkatakrishnan; Beng Heok Tan; C. S. Chin
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Paper Abstract

Dynamic parameter measurement is very important for disk- slider interface design. Laser Doppler Vibrometer has been the most favorite instrument for this purpose due to its non-contact, high accuracy and high resolution. However, LDV can only give the dynamic data of a particular locate on the entire feature. In order to get the whole field data, a laser beam scanning mechanism has to be implemented. Currently, motor-driven scanning mirror is used to move the measurement probe from one point to another. The mechanical vibrations of the scanning mirror will deteriorate the measurement accuracy. Moreover current scanning LDV can not avoid Pseudo error introduced by the scanning angle. This paper describes a novel scanning LDV optical system embodied an acousto-optic deflector scanning mechanism. It can not only eliminate the Pseudo error, but also improve the measurement accuracy since there is no mechanical motion involved. Promising results have been obtain from the preliminary experiments carried out for measurement of out- of-plane runout of magnetic disk, vibration of slider relative to the surface of the rotating magnetic disk, and flying height along the traveling edge.

Paper Details

Date Published: 22 May 2000
PDF: 6 pages
Proc. SPIE 4072, Fourth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, (22 May 2000); doi: 10.1117/12.386745
Show Author Affiliations
Bryan Kok Ann Ngoi, Nanyang Technological Univ. (Singapore)
Krishnan Venkatakrishnan, Nanyang Technological Univ. (Singapore)
Beng Heok Tan, Nanyang Technological Univ. (Singapore)
C. S. Chin, Nanyang Technological Univ. (Singapore)

Published in SPIE Proceedings Vol. 4072:
Fourth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications
Enrico Primo Tomasini, Editor(s)

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