US4728844A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezoelectric transducer and components therefor
Assignee: Cogent Ltd
•
Filing: 1986-07-29
•
Granted: 1988-03-01
•
Expires: 2006-07-29
Abstract
Abstract A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element extending across the opening has a casing containing a backing material in direct contact with the piezoelectric element. The backing material comprises a polymeric composition which may contain a heavy metal oxide, e.g. BiO, or a metal, e.g. Ni, in particulate form, and/or may contain particles of a material of lower specific gravity than the surrounding composition, the distribution of said particles being such that they are most concentrated in a region remote from the piezoelectric element and are least concentrated or essentially absent in the region immediately adjacent the piezoelectric element.
Inventors
- 👤 Paul Wilson
- 👤 Peter Kent
- 👤 Duncan Stewart
- 👤 Robert Crocker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 12:09
CPC Classifications
H; H10; H10D; H10D62/00; H10D62/10; H10D62/13; H10N; H10N30/00; H10N30/01; H10N30/06; H10N30/30; H10N30/308; Y; Y10; Y10S; Y10S310/00; Y10S310/80
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
93 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing particles of a material of lower specific gravity than the surrounding composition, the distribution of said particles being such that they are most concentrated in a region remote from the piezoelectric element and are least concentrated or essentially absent in the region immediately adjacent the piezoelectric element.
Claim 2
Dependent Claim
93 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing particles of a material of lower specific gravity than the surrounding composition, the distribution of said particles being such that they are most concentrated in a region remote from the piezoelectric element and are least concentrated or essentially absent in the region immediately adjacent the piezoelectric element.
Claim 3
Dependent Claim
16 words
A piezoelectric transducer according to claim 1 wherein said particles comprise PVdF or a PVdF/TrFE copolymer.
Claim 4
Dependent Claim
20 words
A piezoelectric transducer according to claim 2 wherein the polymeric composition contains also bismuth oxide and nickel in particulate form.
Claim 5
Dependent Claim
51 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing bismuth oxide in particulate form.
Claim 6
Dependent Claim
51 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing bismuth oxide in particulate form.
Claim 7
Dependent Claim
54 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing nickel and bismuth oxide, each in particulate form.
Claim 8
Dependent Claim
54 words
A piezoelectric transducer comprising a casing having an opening in one face and a piezoelectric element of a piezoelectric plastics material extending across the opening, the casing containing a backing material in direct contact with the piezoelectric element, the backing material comprising a polymeric composition containing nickel and bismuth oxide, each in particulate form.
References Cited (Backward Citations)
US2707755A
Cited
US3189767A
Cited
US3546012A
Cited
US3789656A
Cited
US4240004A
Cited
US4430593A
Cited
US4297607A
Cited
US4373401A
Cited
US4381470A
Cited
US4528652A
Cited
US4523122A
Cited
US4571520A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |