Patent US4716332A successfully refreshed from Google Patents.
US4716332A
Expired / Lapsed
US
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Piezoelectric vibrator
Assignee: Asahi Dempa Co Ltd
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Filing: 1986-06-09
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Granted: 1987-12-29
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Expires: 2006-06-09
Abstract
Abstract A piezoelectric vibrator of thickness-shear mode including a vibrating plate made of AT-cut quartz and a pair of electrodes applied on major surfaces of the vibrating plate in opposition to each other. A part of a contour of the vibrating plate is made closer to the electrode by cutting off a corner of a square vibrating plate. An impedance of the piezoelectric vibrator for a fundamental vibration is extremely increased to suppress the fundamental vibration and thus the piezoelectric vibrator can vibrate stably at a third overtone frequency.
Inventors
- 👤 Hitoaki Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:33
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/02; H03H9/02007; H03H9/02062; H03H9/0207; H03H9/15; H03H9/17; H03H9/19
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
138 words
In a piezoelectric vibrator vibrating at a third overtone frequency comprising a vibrating plate made of piezoelectric material and having opposite major surfaces, and a pair of electrodes applied on said major surfaces in opposition to each other, the improvement wherein said vibrating plate comprises a substantially square plate having at least two adjacent corners cut off along oblique planes substantially perpendicular to said plate and spaced from an axis passing through a center of said plate, said plate has a center of gravity eccentric with respect to a center of gravity of each of said pairs of electrodes, and an impedance of the vibrator for said third overtone frequency is smaller than one-third of an impedance of a vibrator for a fundamental frequency, so that a fundamental vibration is suppressed and a third overtone vibration is enhanced.
Claim 2
Dependent Claim
138 words
In a piezoelectric vibrator vibrating at a third overtone frequency comprising a vibrating plate made of piezoelectric material and having opposite major surfaces, and a pair of electrodes applied on said major surfaces in opposition to each other, the improvement wherein said vibrating plate comprises a substantially square plate having at least two adjacent corners cut off along oblique planes substantially perpendicular to said plate and spaced from an axis passing through a center of said plate, said plate has a center of gravity eccentric with respect to a center of gravity of each of said pairs of electrodes, and an impedance of the vibrator for said third overtone frequency is smaller than one-third of an impedance of a vibrator for a fundamental frequency, so that a fundamental vibration is suppressed and a third overtone vibration is enhanced.
Claim 3
Dependent Claim
14 words
A vibrator according to claim 1, wherein said vibrating plate is made of quartz.
Claim 4
Dependent Claim
31 words
A vibrator according to claim 1, wherein the vibrating plate has a thickness of about 0.21 mm and the piezoelectric vibrator is vibrated at the third overtone frequency of 24 MHz.
Claim 5
Dependent Claim
31 words
A vibrator according to claim 1, wherein the vibrating plate has a thickness of about 0.167 mm and the piezoelectric vibrator is vibrated at the third overtone frequency of 30 MHz.
Claim 6
Dependent Claim
26 words
The vibrator as in claim 1, wherein said adjacent corners are cut off symmetrically with respect to said axis passing through said center of said plate.
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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) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |