A new directional acoustic lens: V-groove lens

Date
1993
Advisor
Instructor
Source Title
Proceedings of the Ultrasonics Symposium, IEEE 1993
Print ISSN
1051-0117
Electronic ISSN
Publisher
IEEE
Volume
Issue
Pages
583 - 586
Language
English
Type
Conference Paper
Journal Title
Journal ISSN
Volume Title
Abstract

A new directional acoustic lens is introduced. The geometry is very similar to the line-focus lens except the lens cavity, which is shaped as a groove with flat-bottom V cross section. The slanted planar edges of the groove are inclined in order to generate waves incident on the object surface at a critical angle. Hence, the edges of the groove act like two wedge transducers facing each other. The cross section of the lens is the same as that of the Lamb Wave Lens. Therefore, it enjoys the same sensitivity to surface wave excitations. On the other hand, since the cross section remains the same along one of the lateral directions, it has directional properties very similar to that of the Line Focus Beam Lens. The waves normally incident on the object surface generated from the flat-bottom, interfere with those at the critical angle, giving rise to a V(Z) effect. Calculated responses of the lens are presented for silicon (001) surface as a function of crystal orientation. The calculated curves are compared with measurement results. The leaky wave velocities are extracted from the measurement results using the conventional FFT algorithm. A new model based algorithm is proposed for extracting the velocity information from V(Z) data.

Course
Other identifiers
Book Title
Keywords
Acoustic transducers, Acoustic wave velocity, Algorithms, Crystal orientation, Data reduction, Fast Fourier transforms, Focusing, Frequency response, Geometry, Lenses, Mathematical models, Semiconducting silicon, Critical angle, Directional acoustic lenses, V groove lens, V(Z) effect, Acoustic devices
Citation
Published Version (Please cite this version)