A MEMS device may include a first electrode region; a first piezoelectric layer arranged over the first electrode region; a second electrode region arranged over the first piezoelectric layer; a second piezoelectric layer arranged over the first piezoelectric layer and the second electrode region; a third electrode region arranged over the second piezoelectric layer; a first input port coupled to the first electrode region and/or the second electrode region for providing a first electrical signal to the first piezoelectric layer to generate a first vibration in the first piezoelectric layer; a second input port coupled to the second electrode region and/or the third electrode region for providing a second electrical signal to the second piezoelectric layer to generate a second vibration in the second piezoelectric layer; and an output port configured to receive an output signal including a superposition of the first vibration and the second vibration.

A dual frequency ultrasound transducer includes a high frequency ultrasound array and a low frequency transducer positioned behind or proximal to the high frequency ultrasound array. In one embodiment, a dampening material is positioned between a rear surface of the high frequency array and the a front surface of the low frequency array. The dampening preferably is high absorbing of signals at the frequency of the high frequency array but passes signals at the frequency of the low frequency transducer with little attenuation. In additional, or alternatively, the low frequency can angled with respect to the plane of the high frequency transducer to reduce inter-stack multipath reflections. Beamforming delays compensate for the differences in physical distances between the elements of the low frequency transducer and the plane of the high frequency transducer.

A system includes a first transducer configured as an actuator. The first transducer is in communication with a surface of a structure. A second transducer is configured as a sensor. The second transducer is in communication with the surface. A third transducer is configured as a sensor. The third transducer is in communication with the surface and separated from the second transduce by an area. A digitizing unit receives signals from the second transducer and the third transducer. The digitizing unit communicates a plurality of frequency signals for the first transducer. A computing unit communicates the plurality of frequency signals to the digitizing unit, receives digitized signals from the digitizing unit, and calculates a Frequency Response Function from the digitized signals. Changes to the Frequency Response Function indicate a change to physical properties of the structure.

A surgical instrument includes a transducer assembly with a housing having a conduit section and a base portion. A fluid passageway is defined through the conduit and base portion, an ultrasonic transducer including a plurality of piezoelectric elements and a plurality of electrodes are arranged in a stack configuration, where an electrode is located between each pair of piezoelectric elements. A first borehole is defined through the ultrasonic transducer and an end mass having a second borehole defined therethrough. A surface of the end mass is positioned adjacent a first end of the ultrasonic transducer, the end mass is configured to engage with the housing, and the conduit section of the housing is configured to pass through the second borehole of the end mass. The end mass is configured to compress the ultrasonic transducer against a surface of the housing when the end mass is engaged with the housing.

A micromachined ultrasonic transducer (MUT) which comprises a first piezoelectric layer and a second piezoelectric layer. The first piezoelectric layer is disposed between a first electrode and a second electrode. The second piezoelectric layer is disposed between the second electrode and a third electrode. At least the first electrode has first and second ends along a first axis, one or more of which is defined by a radius of curvature R. A second axis normal to the first passes through a midpoint of the first axis. A half-width of the first electrode is defined by a length L measured from the midpoint, in the direction of the second axis, to an outer perimeter of the first electrode. A total width of the first electrode at its narrowest point along the first axis is at most 2L such that the first electrode has a concave shape. R/L is greater than 1.

Methods, systems and devices are disclosed for controlling self-induced acoustic interference. In one embodiment, a first piezoelectric transducer to which a first excitation signal is applied, generates back side acoustic waves that are transmitted from a back side of the first piezoelectric transducer into a backing material layer. A second piezoelectric transducer coupled to a back side of the backing material layer generates a first calibration response to the back side acoustic waves. An interference signal profile is generated based, at least in part, on the first calibration response and may be used to filter interference signal components and/or to generate a control signal to be applied to the second piezoelectric transducer during measurement cycles.

A bender bar transducer having stacked encapsulated actuators provides improved acoustic power over a wider frequency range, low applied voltage requirements and consistent part-to-part performance.

A dual frequency ultrasonic and sonic actuator with constrained impact mass is presented. According to one aspect, displacement of the impact mass is constrained by cavity to which ultrasonic stress from the tip of a horn is applied. According to another aspect, the displacement of the impact mass is constrained by a spring attached to the tip of the horn. According to another aspect, the displacement of the impact mass is constrained by a flexure. The constrained impact mass converts the ultrasonic stress to lower frequency sonic stress that is coupled to a transmitting element for transmission through a surface. According to one aspect, the transmitting element is a longitudinal probe. According to another aspect, the transmitting element is a drill bit used to penetrate though the surface. According to another aspect, the transmitting element is a thumper used to transmit elastic waves though the surface.

An effective bandwidth in a membrane based ultrasonic transducer is improved by a control element (C). The control element (C) is disposed on a first side (10a) of a first membrane (10) of the transducer to increase or decrease a displacement amplitude of the first membrane (10) towards the first side (10a) and/or the opposite, second side (10b). This induces a displacement asymmetry (Za< >Zb) in a motion of the first membrane (10) during a first vibration (V1) of the first membrane (10) to the first side (10a) compared to the second side (10b). The displacement asymmetry may result in improved bandwidth.

Control console for a powered surgical tool (310) that includes a transformer (250) with a secondary winding (264) across which the tool drive signal is present. Also internal to the transformer is a matched current source that consists of leakage control winding (246) and a capacitor. The current sourced by the matched current source at least partially cancels out leakage current that may be present.