US4633204A
Expired / Lapsed
US
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Mechanical filter
Assignee: Fujitsu Ltd
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Filing: 1985-08-26
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Granted: 1986-12-30
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Expires: 2005-08-26
Abstract
Abstract A mechanical filter having as its major part at least one longitudinal vibration mode vibrator, includes a piezoelectric ceramic plate an electrode pair attached to top and bottom surfaces thereof. The piezoelectric ceramic plate is polarized in its thickness direction to form at least two polarized regions, the polarization directions being different from each other.
Inventors
- 👤 Takashi Gounji
- 👤 Shinichi Yamamoto
- 👤 Teruo Kawatsu
- 👤 Yoshiro Tomikawa
- 👤 Masashi Konno
- 👤 Toshiharu Ogasawara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 02:51
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/46; H03H9/54; H03H9/56; H03H9/562; H03H9/02; H03H9/02007; H03H9/02062; H03H9/0207; H03H9/15; H03H9/17; H03H9/178; H03H9/566
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
119 words
A mechanical filter including at least one vibrator, comprising: a piezoelectric ceramic plate, formed as a rectangular parallelepiped with mutually perpendicular length, width and thickness axes, polarized substantially along the thickness axis, said piezoelectric ceramic plate divided along the length axis into a plurality of polarized regions aligned with each other, each two adjacent regions polarized in different directions; and an electrode pair, attached to opposing surface of said piezoelectric ceramic plate substantially perpendicular to the thickness axis, for inducing an alternating current electric field therebetween, both electrodes in said electrode pair contacting more than one of said polarized regions and said at least one vibrator vibrating in a longitudinal mode by compression and elongation along the length axis.
Claim 2
Dependent Claim
119 words
A mechanical filter including at least one vibrator, comprising: a piezoelectric ceramic plate, formed as a rectangular parallelepiped with mutually perpendicular length, width and thickness axes, polarized substantially along the thickness axis, said piezoelectric ceramic plate divided along the length axis into a plurality of polarized regions aligned with each other, each two adjacent regions polarized in different directions; and an electrode pair, attached to opposing surface of said piezoelectric ceramic plate substantially perpendicular to the thickness axis, for inducing an alternating current electric field therebetween, both electrodes in said electrode pair contacting more than one of said polarized regions and said at least one vibrator vibrating in a longitudinal mode by compression and elongation along the length axis.
Claim 3
Dependent Claim
20 words
A mechanical filter as set forth in claim 1, wherein each said two adjacent regions are polarized in opposite directions.
Claim 4
Dependent Claim
21 words
A mechanical filter as set forth in claim 2, wherein each electrode in said electrode pair is made of metal film.
Claim 5
Dependent Claim
28 words
A mechanical filter as set forth in claim 2, wherein each electrode in said electrode pair is made of a constant modulus alloy and forms a strip-like electrode.
Claim 6
Dependent Claim
41 words
A mechanical filter as set forth in claim 4, wherein a non-unitary positive integer number n of said polarized regions are formed in said piezoelectric ceramic plate and said mechanical filter provides a filtering function driven under an n-th order mode.
Claim 7
Dependent Claim
45 words
A mechanical filter as set forth in claim 5, wherein said piezoelectric ceramic plate and said electrode pair have centers, and wherein said electrode pair is shorter along the length axis than said piezoelectric ceramic plate and the centers thereof are aligned with each other.
Claim 8
Dependent Claim
101 words
A mechanical filter as set forth in claim 6, wherein two identical vibrators are employed, each being driven under a second order mode due to said polarized regions being two in number, and wherein said mechanical filter further comprises a first coupler and a second coupler, respectively coupling said identical vibrators at a first intermediate position between a first nodal point under the fourth order mode and a first nodal point under the sixth order mode, and a second intermediate position between a second nodal point under the fourth order mode and a second nodal point under the sixth order mode.
Claim 9
Dependent Claim
49 words
A mechanical filter as set forth in claim 7, wherein, in each of said identical vibrators, said electrode pair has a width substantially identical to that of said piezoelectric ceramic plate and a length k times that of said piezoelectric ceramic plate, where k is between 0.80 and 0.84.
Claim 10
Dependent Claim
41 words
A mechanical filter as set forth in claim 2, wherein an even positive integer number n of said polarized regions are formed in said piezoelectric ceramic plate and said mechanical filter provides a filtering function driven under an n-th order mode.
Claim 11
Dependent Claim
40 words
A mechanical filter as set forth in claim 1, wherein each said two adjacent regions are polarized in opposite directions, and wherein said piezoelectric ceramic plate includes a nonpolarized region separating each said two adjacent regions in the length direction.
Claim 12
Dependent Claim
21 words
A mechanical filter as set forth in claim 10, wherein each electrode in said electrode pair is made of metal film.
Claim 13
Dependent Claim
28 words
A mechanical filter as set forth in claim 10, wherein each electrode in said electrode pair is made of a constant modulus alloy and forms a strip-like electrode.
Claim 14
Dependent Claim
40 words
A mechanical filter as set forth in claim 12, wherein non-unitary positive integer number n of said polarized regions are formed in said piezoelectric ceramic plate and said mechanical filter provides a filtering function driven under an nth order mode.
Claim 15
Dependent Claim
45 words
A mechanical filter as set forth in claim 13, wherein said piezoelectric ceramic plate and said electrode pair have centers, and wherein said electrode pair is shorter along the length axis than said piezoelectric ceramic plate and the centers thereof are aligned with each other.
Claim 16
Dependent Claim
101 words
A mechanical filter as set forth in claim 14, wherein two identical vibrators are employed, each being driven under a second order mode due to said polarized regions being two in number, and wherein said mechanical filter further comprises a first coupler and a second coupler, respectively coupling said identical vibrators at a first intermediate position between a first nodal point under the fourth order mode and a first nodal point under the sixth order mode, and a second intermediate position between a second nodal point under the fourth order mode and a second nodal point under the sixth order mode.
Claim 17
Dependent Claim
50 words
A mechanical filter as set forth in claim 15, wherein, in each of said identical vibrators, said electrode pair has a width substantially identical to that of the said piezoelectric ceramic plate and a length k times that of said piezoelectric ceramic plate, where k is between 0.80 and 0.84.
Claim 18
Dependent Claim
128 words
A mechanical filter including a least one vibrator, comprising: a piezoelectric ceramic plate, formed as a rectangular parallelepiped with mutually perpendicular length, width and thickness axes, having two substantially adjacent regions polarized in opposite directions along the thickness axis and dividing said piezoelectric ceramic plate along the length axis; a common electrode formed on a first surface substantially perpendicular to the thickness axis; four opposing electrodes formed on a second surface opposite the first surface, each of said four opposing electrodes formed in a different corner of the second surface; and means for supplying alternating current to said common and four opposing electrodes to form an electric field therebetween to vibrate said piezoelectric ceramic plate in both a longitudinal mode, along the length axis, and a flexural mode.
Claim 19
Dependent Claim
128 words
A mechanical filter including a least one vibrator, comprising: a piezoelectric ceramic plate, formed as a rectangular parallelepiped with mutually perpendicular length, width and thickness axes, having two substantially adjacent regions polarized in opposite directions along the thickness axis and dividing said piezoelectric ceramic plate along the length axis; a common electrode formed on a first surface substantially perpendicular to the thickness axis; four opposing electrodes formed on a second surface opposite the first surface, each of said four opposing electrodes formed in a different corner of the second surface; and means for supplying alternating current to said common and four opposing electrodes to form an electric field therebetween to vibrate said piezoelectric ceramic plate in both a longitudinal mode, along the length axis, and a flexural mode.
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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) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |