OSCILLATING ELEMENT FOR A MULTIPLE RESONANT FREQUENCY ULTRASONIC TRANSDUCER

摘要

The oscillating system of the invention consists of a mounting element (6e) as an oscillating member, and one piezoelectric oscillating element (2) per mounting element (6e) to initiate the oscillation of the oscillating member. Said oscillating system is to be used in an ultrasonic transducer (TR). The oscillating element (2) is mechanically connected to the mounting element (6e) in the form of a glued connection by means of an adhesive. The oscillating system consisting of the mounting element (6e) and the oscillating element (2) is mechanically connected to a housing (1, 1a, 1c) of an ultrasonic transducer (TR) by means of en elastic adhesive (3). The shortest connecting line (L) between the center of gravity of the oscillating element (2) and the housing (1) intersects the elastic adhesive (3). Unlike in the prior art, the oscillating system consisting of the mounting element (6e) and the oscillating element (2) has at least two or more different mechanical resonant frequencies when the oscillating element (2) is triggered by a triggering circuit, at least one of said resonant frequencies being different from the three prior art natural frequencies of the piezoelectric oscillating element (2) and the frequencies of the corresponding harmonics, the natural frequencies being natural frequencies of the oscillating element (2) without the mounted mounting element (6e). The mounting element (6e) has at least one opening (9b) and/or recess and/or depression and/or protuberance. An example of a protuberance is an acoustic stub (10) which can be acoustically terminated or shorted by an additional adhesive (3b). The ratio of the magnitude of the second resonant frequency to the magnitude of the first resonant frequency depends on the diameter or the position of the opening (9b) and/or the recess and/or the depression and/or on the length of the protuberance (10) on the mounting element (6e).