US4544857A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High electromechanical-coupling coefficient surface acoustic wave device
Assignee: NRS Technologies Inc
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Filing: 1983-08-29
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Granted: 1985-10-01
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Expires: 2003-08-29
Abstract
Abstract A high electromechanical-coupling surface acoustic wave device has a lithium niobate rotated Y-cut crystal as a piezoelectric substrate, and a thin high-density film formed on a predetermined portion of the lithium niobate rotated Y-cut crystal which includes at least a propagation path along which the surface acoustic wave propagates. A Love wave propagates in the thin or thick high-density film on the surface of the lithium niobate rotated Y-cut crystal substrate, so that the electromechanical coupling coefficient of the thin film can be improved, and spurious response caused by a Rayleigh wave can be eliminated.
Inventors
- 👤 Hiroshi Shimizu
- 👤 Yasuyuki Mizunuma
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 17:16
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02543; H03H9/02559
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
55 words
A high electromechanical coupling surface acoustic wave device comprising a rotated Y-cut lithium niobate crystal substrate for propagating a Love wave mode along a propagation path, and a thin high density film formed on said propagation path on said substrate and having a thickness that reduces the electromechanical coupling coefficient of Rayleigh waves to zero.
Claim 2
Dependent Claim
55 words
A high electromechanical coupling surface acoustic wave device comprising a rotated Y-cut lithium niobate crystal substrate for propagating a Love wave mode along a propagation path, and a thin high density film formed on said propagation path on said substrate and having a thickness that reduces the electromechanical coupling coefficient of Rayleigh waves to zero.
Claim 3
Dependent Claim
15 words
A device according to claim 1, wherein said thin film is made of a metal.
Claim 4
Dependent Claim
21 words
A device according to claim 2, wherein said metal is selected from the group consisting of gold, silver, platinum and copper.
Claim 5
Dependent Claim
15 words
A device according to claim 1, wherein said thin film is made of a dielectric.
Claim 6
Dependent Claim
25 words
A device according to claim 4, wherein said dielectric is selected from the group consisting of bismuth germanate, bismuth oxide, zinc oxide, and tungsten oxide.
Claim 7
Dependent Claim
31 words
A device according to claim 3, wherein said metal is silver and an angle of rotation of said rotated Y-cut lithium niobate crystal is in the range of 30° to 60°.
Claim 8
Dependent Claim
60 words
A device according to claim 5, wherein said dielectric is bismuth germanate and the ratio H/λ N is in the range of 4×10 -2 to 5×10 -2 , where H is the thickness of said film and λ N is the wavelength of a shear wave in said lithium niobate crystal corresponding to the frequency of said surface acoustic wave.
References Cited (Backward Citations)
US3795879A
Cited
US4480237A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-30 | 1989-04-01 | 1989-10-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-30 | 1993-04-01 | 1993-10-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-30 | 1997-04-01 | 1997-10-01 | $7700.00 | Window Closed / Lapsed |