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Patent US4501987A successfully refreshed from Google Patents.
US4501987A
Expired / Lapsed
US
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Surface acoustic wave transducer using a split-finger electrode on a multi-layered substrate
Assignee: Panasonic Holdings Corp
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Filing: 1981-12-03
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Granted: 1985-02-26
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Expires: 2001-12-03
Abstract
Abstract A surface acoustic wave transducer has a multilayered substrate which is made of a nonpiezoelectric plate which has a surface which is coated with a piezoelectric film, and has an interdigital electrode which is disposed on or under the surface of the piezoelectric film. The interdigital electrode has a split structure and the phase velocity of the surface acoustic wave of the piezoelectric film is smaller than that of the nonpiezoelectric plate.
Inventors
- 👤 Tsuneo Mitsuyu
- 👤 Shusuke Ono
- 👤 Ritsuo Inaba
- 👤 Kiyotaka Wasa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:31
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02535; H03H9/02543; H03H9/02574
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
144 words
A surface acoustic wave transducer comprising: a multi-layered substrate having a non-piezoelectric substrate composed of one of either sapphire or α-alumina or silicon and having a zinc oxide piezoelectric film deposited directly thereon, the surface acoustic wave of said piezoelectric film having a smaller phase velocity than that of said non-piezoelectric substrate; and an interdigital electrode formed on a surface of said piezoelectric film, said interdigital electrode having split-type fingers; wherein said non-piezoelectric substrate comprises a (0112) face sapphire crystal, and said piezoelectric film comprises a (1120) face zinc oxide single crystal film, said zinc oxide single crystal film having a thickness h in the range of 0.1<h/λ≦0.5 (where λ is a wavelength of said surface acoustic wave); whereby said thickness of said piezoelectric film is in a range in which the strength of fundamental response is smaller than that of a harmonic response.
Claim 2
Dependent Claim
144 words
A surface acoustic wave transducer comprising: a multi-layered substrate having a non-piezoelectric substrate composed of one of either sapphire or α-alumina or silicon and having a zinc oxide piezoelectric film deposited directly thereon, the surface acoustic wave of said piezoelectric film having a smaller phase velocity than that of said non-piezoelectric substrate; and an interdigital electrode formed on a surface of said piezoelectric film, said interdigital electrode having split-type fingers; wherein said non-piezoelectric substrate comprises a (0112) face sapphire crystal, and said piezoelectric film comprises a (1120) face zinc oxide single crystal film, said zinc oxide single crystal film having a thickness h in the range of 0.1<h/λ≦0.5 (where λ is a wavelength of said surface acoustic wave); whereby said thickness of said piezoelectric film is in a range in which the strength of fundamental response is smaller than that of a harmonic response.
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) | 1988-02-26 | 1988-08-27 | 1989-02-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-02-26 | 1992-08-27 | 1993-02-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-02-26 | 1996-08-27 | 1997-02-26 | $7700.00 | Window Closed / Lapsed |