US4698541A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Broad band acoustic transducer
Assignee: McDonnell Douglas Corp
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Filing: 1985-07-15
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Granted: 1987-10-06
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Expires: 2005-07-15
Abstract
Abstract There is provided by this invention a broad band acoustic transducer comprising a piezoelectric crystal with a two layer dampening backing having very high attenuation properties. Each layer has an impedance matching the acoustical impedance of the crystal, however, the second layer has an attenuating additive that greatly increases its attenuation factor. The surface interface between the two dampening layers is tilted and roughened to induce wave scattering that prevents back reflections.
Inventors
- 👤 Yoseph Bar-Cohen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:32
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0644; B06B1/0662; B06B1/067; G; G10; G10K; G10K11/00; G10K11/002
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
92 words
A broad band accoustic transducer comprising, (a) a piezoelectric crystal having conductive plating on two sides; (b) a first dampening backing layer consisting of tugsten, copper, and indium 50-lead 50 metallurgically bonded to one side of the crystal having an impedance matching the acoustic impedance of the crystal; and (c) a second dampening and attenuation backing layer consisting of tungsten, copper, indium 50-lead 50, and diallyl phthalate metallurigically bonded to the first dampening layer having an impedance matching the acoustic impedance of the first layer and having a very high attenuation factor.
Claim 2
Dependent Claim
92 words
A broad band accoustic transducer comprising, (a) a piezoelectric crystal having conductive plating on two sides; (b) a first dampening backing layer consisting of tugsten, copper, and indium 50-lead 50 metallurgically bonded to one side of the crystal having an impedance matching the acoustic impedance of the crystal; and (c) a second dampening and attenuation backing layer consisting of tungsten, copper, indium 50-lead 50, and diallyl phthalate metallurigically bonded to the first dampening layer having an impedance matching the acoustic impedance of the first layer and having a very high attenuation factor.
Claim 3
Dependent Claim
28 words
A broad band acoustic transducer as recited in claim 1 wherein the attenuation factor of the second dampening and attenuation backing layer is approximately 50 decibels per centimeter.
Claim 4
Dependent Claim
29 words
A broad band acoustic transducer as recited in claim 2 wherein the surface interface between the first and second layers is roughened to induce wave scattering preventing back reflections.
Claim 5
Dependent Claim
29 words
A broad band acoustic transducer as recited in claim 3 wherein the surface interface between the first and second layers is tilted to induce wave scattering preventing back reflections.
Claim 6
Dependent Claim
24 words
A broad band acoustic transducer as recited in claim 4 wherein the surface tilt between the first and second layer is approximately 25 degrees.
Claim 7
Dependent Claim
27 words
A broad band acoustic transducer as recited in claim 3 wherein the volume fraction of the first layer is approximately 0.37 tungsten, 0.17 copper, and 0.46 In50-Pb50.
Claim 8
Dependent Claim
30 words
A broad band acoustic transducer as recited in claim 4 wherein the volume fraction of the second layer is approximately 0.41 tungsten, 0.12 copper, 0.46 In50-Pb50, and 0.01 diallyl phthalate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-10-05 | 1991-04-06 | 1991-10-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-10-05 | 1995-04-06 | 1995-10-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-10-05 | 1999-04-06 | 1999-10-06 | $7700.00 | Window Closed / Lapsed |