US6328697B1
Expired / Lapsed
US
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Capacitive micromachined ultrasonic transducers with improved capacitive response
Assignee: ATL Ultrasound Inc
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Filing: 2000-10-27
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Granted: 2001-12-11
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Expires: 2020-10-27
Abstract
Abstract An ultrasonic transducer is formed by a plurality of cMUT cells, each has a charged diaphragm plate capacitively opposing an oppositely charged base plate. The diaphragm plate is distended toward the base plate by a bias charge. The base plate includes a central portion elevated toward the center of the diaphragm plate to cause the charge of the cell to be of maximum density at the moving center of the diaphragm plate.
Inventors
- 👤 John Douglas Fraser
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:18
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/0292; B33; B33Y; B33Y10/00; B33Y80/00
Claims Analysis
Total Claims: 25
Claim 1
Independent Claim
89 words
A capacitive micromachined ultrasonic transducer cell comprising: a base plate which retains a first electrical charge; a support having a top and a bottom, said bottom being located on said base plate and; a diaphragm plate which retains a second electrical charge and is supported by the top of said support in a capacitive relationship with said base plate; wherein said base plate includes an elevated region which extends closer to the elevation of the top of said support than the intersection of said support and said base plate.
Claim 2
Dependent Claim
89 words
A capacitive micromachined ultrasonic transducer cell comprising: a base plate which retains a first electrical charge; a support having a top and a bottom, said bottom being located on said base plate and; a diaphragm plate which retains a second electrical charge and is supported by the top of said support in a capacitive relationship with said base plate; wherein said base plate includes an elevated region which extends closer to the elevation of the top of said support than the intersection of said support and said base plate.
Claim 3
Dependent Claim
35 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , further comprising a source of bias potential, coupled to said plates, to distend said diaphragm plate toward said base plate by an attractive coulombic force.
Claim 4
Dependent Claim
33 words
The capacitive micromachined ultrasonic transducer cell of claim 2 , wherein said diaphragm plate, said support, and said base plate define a central cavity, wherein said diaphragm is distended into said central cavity.
Claim 5
Dependent Claim
33 words
The capacitive micromachined ultrasonic transducer cell of claim 3 , wherein said diaphragm plate is peripherally supported by said support, and wherein said elevated region opposes a central region of said diaphragm plate.
Claim 6
Dependent Claim
40 words
The capacitive micromachined ultrasonic transducer cell of claim 4 , wherein said central region of said diaphragm plate is more greatly distended toward said base plate than the peripheral region of said diaphragm plate which is supported by said support.
Claim 7
Dependent Claim
16 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said support is hexagonal shaped.
Claim 8
Dependent Claim
22 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said elevated region comprises a pedestal located on said base plate.
Claim 9
Dependent Claim
17 words
The capacitive micromachined ultrasonic transducer cell of claim 7 , wherein said pedestal exhibits a round shape.
Claim 10
Dependent Claim
17 words
The capacitive micromachined ultrasonic transducer cell of claim 7 , wherein said pedestal exhibits a rectangular shape.
Claim 11
Dependent Claim
17 words
The capacitive micromachined ultrasonic transducer cell of claim 7 , wherein said pedestal exhibits a hexagonal shape.
Claim 12
Dependent Claim
40 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said base plate includes a first conductive electrode which retains said first electrical charge, and wherein said diaphragm includes a second conductive electrode which retains said second electrical charge.
Claim 13
Dependent Claim
21 words
The capacitive micromachined ultrasonic transducer cell of claim 11 , wherein said first and second electrical charges are opposing electrical charges.
Claim 14
Dependent Claim
32 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , further comprising a plurality of cells located on a common base plate, wherein said plurality of cells comprise an ultrasonic transducer element.
Claim 15
Dependent Claim
38 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said diaphragm includes a conductive electrode which retains said second electrical charge; and wherein said conductive electrode extends over a majority of the area of the diaphragm.
Claim 16
Dependent Claim
29 words
The capacitive micromachined ultrasonic transducer cell of claim 14 , wherein said conductive electrode extends over substantially the entire area of the diaphragm inside the periphery of said support.
Claim 17
Dependent Claim
27 words
The capacitive micromachined ultrasonic transducer cell of claim 14 , further including a low impedance conductor coupling said electrode to an a.c. signal or DC bias circuit.
Claim 18
Dependent Claim
21 words
The capacitive micromachined ultrasonic transducer cell of claim 16 , wherein said a.c. signal circuit comprises an ultrasound signal receiver circuit.
Claim 19
Dependent Claim
41 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said diaphragm includes a conductive electrode which retains said second electrical charge; and wherein said conductive electrode extends over a plurality of cells which operate as a single transducer element.
Claim 20
Dependent Claim
34 words
The capacitive micromachined ultrasonic transducer cell of claim 1 , wherein said cell is fabricated on a substrate, and further comprising a signal amplifier, coupled to said cell, and fabricated on the same substrate.
Claim 21
Dependent Claim
87 words
A capacitive micromachined ultrasonic transducer cell comprising: a base plate which retains a first electrical charge; a support having a top and a bottom, said bottom being located on said base plate and; a diaphragm plate which retains a second electrical charge and is supported by the top of said support in a capacitive relationship with said base plate; wherein said diaphragm plate includes a downwardly extending region which extends the diaphragm plate charge closer to the base plate than would occur without the downwardly extending region.
Claim 22
Dependent Claim
87 words
A capacitive micromachined ultrasonic transducer cell comprising: a base plate which retains a first electrical charge; a support having a top and a bottom, said bottom being located on said base plate and; a diaphragm plate which retains a second electrical charge and is supported by the top of said support in a capacitive relationship with said base plate; wherein said diaphragm plate includes a downwardly extending region which extends the diaphragm plate charge closer to the base plate than would occur without the downwardly extending region.
Claim 23
Dependent Claim
28 words
The capacitive micromachined ultrasonic transducer cell of claim 20 , wherein the downwardly extending region is suspended from center of the downward facing side of the diaphragm plate.
Claim 24
Dependent Claim
18 words
The capacitive micromachined ultrasonic transducer cell of claim 20 , wherein the diaphragm plate comprises a nonplanar structure.
Claim 25
Dependent Claim
32 words
The capacitive micromachined ultrasonic transducer cell of claim 20 , wherein the downwardly extending region comprises a pedestal extending downwardly from the surface of the diaphragm plate which opposes the base plate.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-12-10 | 2005-06-11 | 2005-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-12-10 | 2009-06-11 | 2009-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-12-10 | 2013-06-11 | 2013-12-11 | $7700.00 | Window Closed / Lapsed |