A broken piezoelectric material in an ultrasonic transducer of an ultrasonic stack of an ultrasonic device is detected by measuring a test piezo coupling constant with a test scan of the ultrasonic stack. The test piezo coupling constant is compared to a previously measured baseline piezo coupling constant. The piezoelectric material is determined to be broken when the test piezo coupling constant is less than the baseline piezo coupling constant by more than a predetermined amount.

An ultrasonic surgical instrument includes a housing, a waveguide extending distally from the housing, an end effector coupled to the distal end of the waveguide, an ultrasonic transducer retained within the housing, and a controller. The ultrasonic transducer is coupled to the proximal end of the waveguide and configured to produce mechanical motion for transmission along the waveguide to the end effector. The controller is configured to control an amplitude of the mechanical motion of the ultrasonic transducer in accordance with at least one amplitude value. The at least one amplitude value is adjusted according to an age of the ultrasonic transducer to compensate for aging of the ultrasonic transducer. Methods for controlling the amplitude of the mechanical motion of an ultrasonic transducer to compensate for aging of the ultrasonic transducer are also provided.

Electroacoustic device (5) comprising: an ultrasonic wave transducer (15) comprising a piezoelectric substrate (10) and first (30) and second (35) electrodes in contact with the piezoelectric substrate, and a carrier (10), the transducer being attached to the carrier and acoustically coupled to the carrier, and the first and second electrodes being sandwiched, at least partly, between the piezoelectric substrate and the carrier, the device being configured to generate an ultrasonic surface wave (W) propagating through the carrier at a distance from the transducer when an electric current passes through the first and second electrodes.

A system and downhole tool comprising an ultrasonic transducer with a piezoelectric material embedded in a backing and a method of determining a parameter using the ultrasonic transducer. A self-noise of the transducer can be reduced by the piezoelectric material being at least partially embedded in the backing. The ultrasonic transducer can include an encapsulating material that encapsulates the backing.

An apparatus includes an ultrasonic sensor stack configured to transmit and receive ultrasonic waves. The ultrasonic sensor stack includes at least a thin film transistor layer, a piezoelectric layer, and a thin electrode layer. The ultrasonic sensor stack further includes a tunable metal layer coupled to the thin electrode layer and an acoustic layer coupled to the tunable metal layer, where the tunable metal layer has a thickness greater than a thickness of the thin electrode layer. The thickness of the tunable metal layer may be configured to match a peak frequency in an ultrasonic frequency range of the ultrasonic waves transmitted by the ultrasonic sensor stack. In some implementations, the tunable metal layer includes a copper layer and the acoustic layer includes polyimide or polyethylene terephthalate.

An ultrasonic transducer is described. The ultrasonic transducer comprises a membrane and a substrate disposed opposite the membrane such that a cavity is formed therebetween. The substrate comprises an electrode region and pedestals protruding from a surface of the substrate and having a height greater than a height of the electrode region, the pedestals being electrically isolated from the electrode region.

An ultrasound transducer unit including a plurality of ultrasound transducers transmits and receives ultrasound waves to and from an inside of a subject. In a case where a checking operation unit is operated, a controller controls a driving voltage supply unit such that a driving voltage is supplied with all of the plurality of ultrasound transducers as driving target transducers. In a case where the checking operation unit is operated, a depolarization determination unit calculates, for each ultrasound transducer, a reception sensitivity in a case where an ultrasound wave is received by driving all of the plurality of ultrasound transducers as the driving target transducers, and determines whether or not a depolarization determination value calculated from the reception sensitivity of each ultrasound transducer satisfies numerical conditions. If the numerical conditions are satisfied, a polarization voltage supply unit supplies a polarization voltage to each of the plurality of ultrasound transducers.

Techniques for reducing or eliminating cross talk in row-column addressed array (RCA) probes are described. A diode can be connected in series to piezo-composite element in each pixel of the RCA to prevent cross talk. A resistor can also be provided in parallel to the piezo-composite element for discharging purposes and providing DC paths for the forward and backward bias voltages to the diodes. Thus. RCA probes using the techniques disclosed herein can use sub-apertures for, among other things, inspecting longitudinal and transverse flaws, and for more efficient local focusing for an acoustic camera without significant cross talk interference.

An acoustic cleaving system are described for initiating and controlling crack propagation. In an embodiment, the system includes an acoustic generator that includes a piezoelectric device; a high-voltage power supply; and an acoustic cleaving circuit. The acoustic cleaving circuit includes a push-pull circuit coupled to the piezoelectric device and coupled to the high-voltage power supply, and a capacitor bank that includes one or more capacitors coupled in parallel to the push-pull circuit. In one embodiment, the push-pull circuit is for receiving at least one input signal and for producing an amplified output signal to drive the piezoelectric device.

An acoustic system is described that includes a piezoelectric device; an alternating current (AC) power supply for supplying an AC voltage; an AC-to-direct current (DC) converter coupled to the AC power supply for converting the AC voltage supplied by the AC power supply into DC voltage; a function generator for producing an input signal at a resonant frequency of the piezoelectric device; and an amplifier coupled to the AC-to-DC converter, the function generator, and the piezoelectric device, where the amplifier is for producing an output signal by amplifying the input signal according to the DC voltage and driving the piezoelectric device using the output signal.