CMUTs with a high-k dielectric
First Claim
1. A capacitive ultrasound transducer, comprising:
- a first electrode;
a second electrode;
a membrane electrode, the third electrode including a central region disposed in fully collapsed relation without a gap with the first electrode, and a peripheral region disposed outward of the central region and disposed in a spaced relation across a gap from the second electrode; and
a layer of a high dielectric constant material disposed between the membrane electrode and the first electrode and between the membrane electrode and the second electrode,wherein the peripheral region of the third electrode oscillates relative to the second electrode, andwherein the capacitive ultrasound transducer operates in a collapsed mode with the high dielectric constant material sandwiched between the membrane electrode and the first electrode.
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Accused Products
Abstract
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.
70 Citations
22 Claims
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1. A capacitive ultrasound transducer, comprising:
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a first electrode; a second electrode; a membrane electrode, the third electrode including a central region disposed in fully collapsed relation without a gap with the first electrode, and a peripheral region disposed outward of the central region and disposed in a spaced relation across a gap from the second electrode; and a layer of a high dielectric constant material disposed between the membrane electrode and the first electrode and between the membrane electrode and the second electrode, wherein the peripheral region of the third electrode oscillates relative to the second electrode, and wherein the capacitive ultrasound transducer operates in a collapsed mode with the high dielectric constant material sandwiched between the membrane electrode and the first electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A capacitive ultrasound transducer comprising:
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a first electrode; a second electrode; 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; and 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, and further including a piezoelectric layer and a fourth electrode, and wherein the third and fourth electrodes are cooperative for applying an electric field to the piezoelectric layer. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A method of operating a capacitive ultrasound transducer, comprising:
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providing a capacitive ultrasound transducer including a first electrode, a second electrode, a membrane electrode in collapsibly spaced relation with respect to each of the first and second electrodes, and a layer of a high dielectric constant material disposed between the membrane electrode and the first electrode, and between the membrane electrode and the second electrode; fully collapsing a central region of the membrane electrode with respect to the first electrode such that the layer of a high dielectric constant material is sandwiched therebetween; and oscillating, with respect to the second electrode, a peripheral region of the membrane electrode disposed outward of the central region.
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18. A method of operating a capacitive ultrasound transducer, comprising:
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providing a capacitive ultrasound transducer including a first electrode, a second electrode, a third electrode in collapsibly spaced relation with respect to each of the first and second electrodes, and 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; collapsing a central region of the third electrode with respect to the first electrode such that the layer of a high dielectric constant material is sandwiched therebetween; and oscillating, with respect to the second electrode, a peripheral region of the third electrode disposed outward of the central region, wherein the capacitive ultrasound transducer further comprises a piezoelectric layer and a fourth electrode, and the method further comprises cooperatively employing the third and fourth electrodes to produce piezoelectric coupling with respect to the piezoelectric layer. - View Dependent Claims (19, 20, 21, 22)
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Specification