PURPOSE: To make a side lobe value small and obtain a stable beam formation by bonding a piezoelectric ceramic oscillator to an inner side of a bottom surface part of a case of truncated cone shape in section, and by holding the case by a resilient oscillation preventing body having an ellipsoidal hole of a longer major axis and minor axis than the diameter of the bottom surface part.
CONSTITUTION: An oscillator 3 is bonded to an inner side of a bottom surface part 1 of a case 2 of truncated cone shape in section, and the case 2 is held by a resilient oscillation preventing body 7 having an ellipsoidal hole 8 with a major axis (a) and a minor axis (b) which are larger than the diameter of the bottom surface part 1 of the case 2 and shorter than an opening end diameter and an acoustic tube 10 is formed by the ellipsoidal hole 8. A lead wire 5 connects respectively the oscillator 3, the case 2 and an output terminal 6. Thereby, the size and a vertical and horizontal direction ratio of the ultrasonic beam can be selected, a side lobe value can be made small to obtain a stable beam formation.
INOUE HIRONOBU
AZUMA NAOYA
YAMANE TOSHIKI
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