THE INFLUENCE OF COLLIMATORS ON THE FOCUSED ACOUSTIC BEAM

摘要

In this paper are presented the reflected acoustic pressure distributions from a target reflector using two acoustic systems. Use of acoustic systems consists of an unfocused planar transducer to which is attached a spherical or cylindrical lens (TL system). After illustrating, through 3D histograms, the point or line focused acoustic beam, a collimator with a circular aperture was attached to emphasize focused systems (TLC).The effects of collimation on the acoustic pressure distribution for the two systems is shown for the variable TLC system-reflector distances. Collimator sizes, lenses and planar transducer characteristics are also presented in this paper. An emphasized focusing is obtained by placing the aperture at variable distances from the TL system. Experiments were made using an unfocused transducer for 2 MHz and 24 mm diameter and SONIC 137 ULTRA ultrasonic device of the Stav-eley Company. The principal purpose of the paper was to obtain an improved understanding of how collimators modify the acoustic beam of a transducer.