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US4749900A
Expired / Lapsed
US
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Multi-layer acoustic transducer for high frequency ultrasound
Assignee: Leland Stanford Junior University
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Filing: 1986-11-17
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Granted: 1988-06-07
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Expires: 2006-11-17
Abstract
Abstract The invention relates to a multi-layered piezoelectric acoustic transducer for generating layers of the same piezoelectric material are provided such tool alternate layers have different crystallographic orientations and different piezoelectric coupling coefficients. The layers may be provided so that alternate layers have crystallographic orientations which provide maximum electro-acoustic coupling and layers which provide minimum electro-acoustic coupling.
Inventors
- 👤 Babur B. Hadimioglu
- 👤 Butrus T. Khuri-Yakub
- 👤 Calvin F. Quate
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:03
CPC Classifications
B; B06; B06B; B06B1/00; B06B1/02; B06B1/06; B06B1/0607; B06B1/0611; H; H10; H10N; H10N30/00; H10N30/01; H10N30/07; H10N30/074; H10N30/076; H10N30/50; H10N30/80; H10N30/85; H10N30/853; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
116 words
A piezoelectric transducer comprising a substrate, a first conductive layer on said substrate, a multi-layer piezoelectric trnasducer carried on said conductive layer and a conductive layer on the surface of said transducer whereby an electrical field extending between said conductive layers can be applied to said transducer, said transducer characterized in that the layers are formed of the same piezoelectric material with a plurality of first spaced layers having their crystallographic axes aligned with the electric field to provide maximum coupling wiht the electric field and a plurality of second spaced layers having their crystallographic axis at an angle with respect to the field between said first layers to provide low coupling with the electric field.
Claim 2
Dependent Claim
116 words
A piezoelectric transducer comprising a substrate, a first conductive layer on said substrate, a multi-layer piezoelectric trnasducer carried on said conductive layer and a conductive layer on the surface of said transducer whereby an electrical field extending between said conductive layers can be applied to said transducer, said transducer characterized in that the layers are formed of the same piezoelectric material with a plurality of first spaced layers having their crystallographic axes aligned with the electric field to provide maximum coupling wiht the electric field and a plurality of second spaced layers having their crystallographic axis at an angle with respect to the field between said first layers to provide low coupling with the electric field.
Claim 3
Dependent Claim
23 words
A piezoelectric transducer as in claim 1 wherein the thickness of the layers is approximately one-half the wavelength at the acoustic operating frequency.
Claim 4
Dependent Claim
13 words
A piezoelectric transducer as in claim 1 wherein the layers are zinc oxide.
Claim 5
Dependent Claim
37 words
A piezoelectric transducer as in claim 3 wherein the C-axis of said first layers is parallel to the electric field and the C-axis of the second layers is at approximately 40° with respect to the electric field.
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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) | 1991-06-07 | 1991-12-07 | 1992-06-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-06-07 | 1995-12-07 | 1996-06-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-06-07 | 1999-12-07 | 2000-06-07 | $7700.00 | Window Closed / Lapsed |