Broadband piezoelectric ultrasonic transducer for radiating in air
First Claim
1. A broadband ultrasonic transducer arrangement for radiating and/or receiving ultrasonic energy in the medium of air comprising a plurality of piezoelectric transducer elements disposed in registry in a like plurality of substantially parallel planes and respective layers of acoustically inactive material disposed between said transducer elements and maintaining a spacing between transducer elements in adjacent planes which is substantially larger than a thickness of said transducer elements, said acoustically inactive material being dimensionally stable and having an intrinsic acoustic impedance which is lower by a factor of at least approximately eight than the intrinsic acoustic impedance of said transducer elements and having a mechanical attenuation greater than approximately 0.05, said acoustically inactive material forming at least one closed face of said transducer arrangement for emission and/or reception of ultrasonic energy.
0 Assignments
0 Petitions
Accused Products
Abstract
A piezoelectric ultrasonic transducer for radiating ultrasonic energy in the medium of air has a number of piezoceramic ultrasonic radiators disposed in registry within a dimensionally stable carrier block which has an intrinsic acoustic impedance which is lower by a factor of at least eight than that of the piezoceramic material and which has a high mechanical attenuation 1/Qm greater than approximately 0.05. The carrier block is yieldable at at least one closed face thereof for emission and/or reception of ultrasonic energy. The piezoelectric transducer elements may be divided into a number of side-by-side elements which may be individually energized, or may have electrodes connected in series for energizing the individual transducer elements in common. The combined operation of the ultrasonic transducer elements within the carrier block results in an ultrasonic transducer having broadband characteristics matched for ultrasonic transmission in the medium of air of short ultrasonic waveforms and for receiving ultrasonic energy for near-distance detection.
-
Citations
13 Claims
- 1. A broadband ultrasonic transducer arrangement for radiating and/or receiving ultrasonic energy in the medium of air comprising a plurality of piezoelectric transducer elements disposed in registry in a like plurality of substantially parallel planes and respective layers of acoustically inactive material disposed between said transducer elements and maintaining a spacing between transducer elements in adjacent planes which is substantially larger than a thickness of said transducer elements, said acoustically inactive material being dimensionally stable and having an intrinsic acoustic impedance which is lower by a factor of at least approximately eight than the intrinsic acoustic impedance of said transducer elements and having a mechanical attenuation greater than approximately 0.05, said acoustically inactive material forming at least one closed face of said transducer arrangement for emission and/or reception of ultrasonic energy.
Specification