摘要:
A capacitive ultrasound transducer capable of operation in collapsed mode either with a reduced bias voltage, or with no bias voltage, is provided. The transducer includes a substrate that is contoured so that a middle region of the flexible membrane is collapsed against the substrate in the absence of a bias voltage. A non-collapsible gap may exists between the substrate and peripheral regions of the flexible membrane. The contour of the substrate may be such as to strain the flexible membrane past the point of collapse, or to mechanically interfere with the flexible membrane. The substrate may include a further membrane disposed beneath the flexible membrane, the further membrane being contoured so that the flexible membrane is collapsed against it. The substrate may a support disposed beneath the further membrane to deflect a corresponding portion of the further membrane upward toward the flexible membrane. The support may be a post. The transducer may be operated in collapse mode with an improved efficiency (k2eff) as compared to otherwise similar conventional transducers exhibiting comparably uncontoured substrates. A related medical imaging system is provided, which may include an array of such transducers disposed on a common substrate. A method of operating such a transducer is provided that includes operating the transducer in the collapse mode in the absence of a bias voltage.
摘要:
An array of cMUT cells are formed on individually isolated massive plates on a substrate. The mass of each plate provides an inertial force in opposition to the force and motion of transmission by the cell which reduces the resultant translation of motion in the plate. The reduction in motion results in less coupling of acoustic energy into the substrate and contamination of the signals of adjacent cMUT cells by lateral waves. The unwanted wave coupling into the substrate can be further damped by compliant or sparse periodic mounting of the massive plates on the substrate.
摘要:
An ultrasonic diagnostic imaging system for shear wave measurement transmits push pulses into tissue for the generation of shear waves. Characteristics of the shear waves such as their velocity of passage through the tissue are measured to assess properties such as tissue stiffness. The measurements are compensated for effects of background motion by sampling echo signals from the tissue at different times and comparing the samples to detect the presence of relative motion between the ultrasound probe and the region of interest where shear waves are detected. Sensed background motion is used to adjust measured shear wave characteristics.
摘要:
A capacitive ultrasound transducer includes a first electrode, a second electrode, and a third electrode, the third electrode including a central region disposed in collapsibly spaced relation with the first electrode, and a peripheral region disposed outward of the central region and disposed in collapsibly spaced relation with the second electrode. The transducer further includes a layer of a high dielectric constant material disposed between the third electrode and the first electrode, and between the third electrode and the second electrode. The transducer may be operable in a collapsed mode wherein the peripheral region of the third electrode oscillates relative to the second electrode, and the central region of the third electrode is fully collapsed with respect to the first electrode such that the dielectric layer is sandwiched therebetween. Piezoelectric actuation, such as d31 and d33 mode piezoelectric actuation, may further be included. A medical imaging system includes an array of such capacitive ultrasound transducers disposed on a common substrate.
摘要:
The appliance includes an appliance body (12) as well as a system for producing microbubbles (20) and a system for producing an ultrasound signal beam (22) in a frequency range which activates at least some of the microbubbles. The appliance includes at least one of the following: (a) an array of ultrasound transducer elements (40) which produce a plurality of ultrasound signal beams; (b) an amplitude modulation assembly (51) for modulating the amplitude of the ultrasound signal; and (c) a frequency modulation system (61) for changing the frequency of the ultrasound signals over a selected range, to impact a range of microbubble sizes.
摘要:
The apparatus includes a source of gas (air) bubbles (14) in a liquid medium, the gas bubbles having a size range which is associated with the size of bacteria alone or in colonies, on teeth or other surfaces. A source of ultrasound signals (16, 18) has a range of frequencies between 200 kHz and 2 MHz, the ultrasound frequency range including the resonance frequencies of a majority of the bubbles. The application of the ultrasound to the bubble/liquid stream directed toward the biofilm on the teeth results in a dislodging/removal of the biofilm.
摘要:
A capacitive ultrasound transducer includes a first electrode, a second electrode, and a third electrode, the third electrode including a central region disposed in collapsibly spaced relation with the first electrode, and a peripheral region disposed outward of the central region and disposed in collapsibly spaced relation with the second electrode. The transducer further includes a layer of a high dielectric constant material disposed between the third electrode and the first electrode, and between the third electrode and the second electrode. The transducer may be operable in a collapsed mode wherein the peripheral region of the third electrode oscillates relative to the second electrode, and the central region of the third electrode is fully collapsed with respect to the first electrode such that the dielectric layer is sandwiched therebetween. Piezoelectric actuation, such as d31 and d33 mode piezoelectric actuation, may further be included. A medical imaging system includes an array of such capacitive ultrasound transducers disposed on a common substrate.
摘要:
A two dimensional ultrasonic transducer array suitable for three dimensional phased array scanning is formed of hexagonally close packed transducer elements. In a preferred embodiment the transducer elements have a rectilinear shape, allowing the array to be fabricated with conventional dicing saw processes.
摘要:
An ultrasonic diagnostic imaging system for shear wave measurement transmits push pulses in the form of a sheet of energy. The sheet of energy produces a shear wavefront which is a plane wave, which does not suffer from the 1/R radial dissipation of push pulse force as does a conventional push pulse generated along a single push pulse vector. The sheet of energy can be planar, curved, or in some other two or three dimensional shape. A curved sheet of energy can produce a shear wave source which focuses into a thin line, which increases the resolution and sensitivity of the measuring techniques used to detect the shear wave effect.
摘要:
A magnetic connection system suitable for use with a wireless ultrasound probe which utilizes a plurality of magnets to facilitate coupling between said probe and a diagnostic or clinical device in a manner which minimizes the effects of stray magnetic fields on the device.