Electrical biasing of ultrasonic transducers of an ultrasound device is described. The ultrasonic transducers may be capacitive micromachined ultrasonic transducers (CMUTs). The ultrasonic transducers may be grouped together, with the different groups receiving different bias voltages. The bias voltages for the various groups of ultrasonic transducers may be selected to account for differences between the groups.

According to one aspect, there is provided a speaker comprising a body, a surface structure rigidly attached to the body, electro-magnetic deformable plate elements attached to the rigid planar surface structure and configured to bend, when driven with voltage or current source, the surface structure, and electro-magnetic deformable plate element specific band-pass filter for at least one electro-magnetic deformable plate element of the electro-magnetic deformable plate elements, the band-pass filter having at least one electro-magnetic deformable plate element specific pass band.

A method for controlling a system, comprising repeatedly monitoring at least one operational characteristic of a system that includes an ultrasonic transducer, wherein the ultrasonic transducer is powered by an ultrasonic generator and is configured to drive a device at predetermined levels of vibration amplitude, and wherein the ultrasonic generator includes a controller configured to monitor operational parameters of the system; detecting a change in an operational characteristic based on a comparison of the monitored characteristic against a predetermined threshold for that characteristic; inferring a system-use criteria based on the detected change in the operational characteristic; and adapting system control by using the controller to alter the operational characteristic based on the inferred use criteria.

A broadband ultrasonic transducer device (UTD) is disclosed that utilizes a plurality of narrow-band piezo electric elements grouped into single-frequency sub-arrays to provide a relatively simple, highly-reliable deterrent unit (DU) capable of emitting ultrasonic energy over a wide coverage area and at a sound pressure level that meets or exceeds other DU approaches. In an embodiment, the broadband UTD includes a housing portion configured to couple to a plurality of piezo sub-array plates. Each piezo sub-array plate includes a plurality of pockets or cavities to receive respective narrow-band (e.g., 1-3 kHz) piezo electro transducer elements with characteristics, e.g., geometries and material composition, that cause each to emit ultrasonic energy at a particular resonant frequency. A controller of the UTD implements a control scheme to emit ultrasonic energy in a plurality of output modes including a white noise node and a single-frequency mode for deterrence applications.

An ultrasound transducer includes a transducer body configured to generate ultrasound vibration to vibrate a treatment portion that treats a living tissue. The transducer body includes a plurality of piezoelectric elements configured to alternately repeat expansion and contraction according to a supplied drive signal. The plurality of piezoelectric elements are integrally fastened in a state where the plurality of piezoelectric elements are stacked along a direction of expansion and contraction. The plurality of piezoelectric elements include a first piezoelectric element configured to expand at a first timing and contract at a second timing, and a second piezoelectric element whose expansion and contraction timings are different from expansion and contraction timings of the first piezoelectric element. The second piezoelectric element is arranged so that a polarization direction of the second piezoelectric element is a same as a polarization direction of an adjacent piezoelectric element.

Electrical biasing of ultrasonic transducers of an ultrasound device is described. The ultrasonic transducers may be capacitive micromachined ultrasonic transducers (CMUTs). The ultrasonic transducers may be grouped together, with the different groups receiving different bias voltages. The bias voltages for the various groups of ultrasonic transducers may be selected to account for differences between the groups.

A structure of an acoustic transducer array probe for transmission of acoustic waves from a front radiation surface into an acoustic load material, where said acoustic waves can have frequencies in a high frequency (HF) band and further lower frequency (LF1, . . . , LFn, . . . , LFN) bands with N1, arranged in order of decreasing center frequency. The acoustic waves are transmitted from separate high and lower frequency arrays stacked together with matching layers in a thickness dimension into a layered structure, with at least a common radiation surface for said high and lower frequency bands. At least for said common radiation surface at least one lower frequency LFn electro-acoustic structure (n=1, . . . , N) comprises a piezoelectric array with an acoustic isolation section to its front face. The acoustic isolation section includes to the front a section composed of a sequence of L3 matching layers with interchanging low and high characteristic impedances, where the front layer of said section is one of i) a lower characteristic impedance layer, and ii) a higher characteristic impedance layer, and where at least one lower characteristic impedance layer is made of a homogeneous material.

A single critically damped acoustic stack yields a wide frequency range as an acoustic transmitter or as an acoustic transducer having particular use in well integrity determination. The critically damped present acoustic stack utilizes a plurality of stacked acoustic elements such as piezoelectric ceramics that are energized in two manners, providing different center frequencies, each producing a respective center frequency of 100% bandwidth to yield an acoustic stack having a total bandwidth exceeding the bandwidth of an acoustic element or the bandwidth of the plurality of acoustic elements. One manner of energizing is to pulse only one of the acoustic elements. The other manner is to pulse a first acoustic element then pulse a second acoustic element after a delay equal to the amount of time it takes for the first pulse to reach the face of the second acoustic element. The acoustic stack is primarily used in pulse-echo analysis of metal casing wall thickness and cement bond quality detection of wells.

An ultrasonic handpiece assembly has a horn, a rear mass attached to a rear end of the horn, a needle attached to a front end of the horn, a stack of piezoelectric elements arranged coaxially about the horn, and an L-T spring arranged coaxially about the horn behind the stack. The horn includes a low gain section in front of the stack and a high gain section in front of the low gain section. The assembly has a first L-T mode, a T mode, a second L-T mode, and an L mode at different resonant frequencies. The low gain horn section includes a circumferential groove located at a vibrational node of the L-T mode. Frequency separation between the first L-T mode and T mode results in torsional vibration of the first L-T mode interacting constructively with torsional vibration of the T mode, thereby increasing torsional stroke in the T mode.

According to one aspect, there is provided a speaker comprising a body, a surface structure rigidly attached to the body, electro-magnetic deformable plate elements attached to the rigid planar surface structure and configured to bend, when driven with voltage or current source, the surface structure, and electro-magnetic deformable plate element specific band-pass filter for at least one electro-magnetic deformable plate element of the electro-magnetic deformable plate elements, the band-pass filter having at least one electro-magnetic deformable plate element specific pass band.