Electrical impedance normalization for an ultrasonic transducer array
March 10, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2411551 2928068 3922572 Transducer Multi-layer element consisting of piezoelectric ceramic laminations and method of making same Variable acoustic wave energy transfer-characteristic control device Apparatus and method for suppressing mass/spring mode in acoustic imaging transducers Transducer for electronic focal scanning in an ultrasound imaging device Ultrasonic transducer shading Transducer device InventorsApplicationNo. 029212 filed on 03/10/1993US Classes:310/334, Acoustic wave type generator or receiver310/326, Combined with damping structure310/359, More than one poling direction (e.g., Rosen transformer)600/437UltrasonicExaminersPrimary: Budd, Mark O.International ClassH01L 041/08AbstractA two-dimensional ultrasonic transducer array includes a plurality of transducer elements, with each element having a plurality of piezoelectric layers. The transducer elements vary in transverse areas of radiating regions. The effect of the variations in transverse areas on the electrical impedances of the elements is at least partially offset by varying the specific impedance, i.e., impedance per unit area, of the transducer elements in the array. In a preferred embodiment, the specific impedance is varied by selecting the electrical arrangements of piezoelectric layers in each element according to the transverse area of the element. Series, parallel and series-parallel arrangements are employed. This impedance normalization improves the electrical connection of the transducer elements to driving circuitry. In alternative embodiments, impedance normalization is achieved by varying element thicknesses, element materials and/or degrees of poling across the two-dimensional array. | |
