Ultrasound transducer and method for making the same
AssigneeSunnybrook Research Institute
InventorsKullervo Hynynen, Junho Song
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Abstract
The present application provides a multilayer lateral mode coupling method for phased array construction and transducer devices built accordingly. This disclosure describes and demonstrates that the electrical impedance of a phased array can be substantially reduced and readily controlled to be close to the source impedance. The fabrication process is relatively simple and inexpensive. In addition, the elements are robust for use in 1.5, 2, 3 or other dimensional configurations, over an extended period of operation, without structural failure, and providing a high power output required for imaging and/or medical therapy applications.
Claims17
An ultrasound system comprising:
- an ultrasound array comprising a plurality of multilayer lateral mode ultrasound array elements, each multilayer lateral mode ultrasound array element comprising:
- a plurality of piezoelectric layers stacked along a first direction to form a piezoelectric stack, each layer having a common thickness;
- and
- a plurality of electrodes comprising outer electrodes formed on outer surfaces of said piezoelectric stack and inner electrodes sandwiched between respective piezoelectric layers of said piezoelectric stack;
- wherein a first set of electrodes of said plurality of electrodes are connected in parallel and a second set of electrodes of said plurality of electrodes of said plurality of electrodes are connected in parallel, said first set of electrodes being interleaved with said second set of electrodes;
- electrical driving circuitry operatively coupled to said ultrasound array, in the absence of impedance matching circuitry, for delivering respective driving signals between said first set of electrodes and said second set of electrodes of each multilayer lateral mode ultrasound array element with frequency content suitable for exciting a lateral mode resonance of each piezoelectric layer, such that ultrasound energy is responsively emitted in a second direction that is perpendicular to the first direction;
- wherein each piezoelectric layer, when driven laterally to excite the lateral mode resonance, has a common per-layer electrical impedance, and wherein each multilayer lateral mode ultrasound array element, when driven to laterally to excite the lateral mode resonance of each piezoelectrical layer, has a net electrical impedance equal to the per-layer electrical impedance divided by the number of piezoelectric layers, and wherein the number of piezoelectric layers corresponds to a configuration that minimizes an electrical impedance mismatch between the net electrical impedance of said each multilayer lateral mode ultrasound array element and an electrical impedance of said electrical driving circuitry, thereby facilitating driving of the ultrasound array in the absence of impedance matching circuitry.
Dependencies are inferred from the claim text.