US4659956A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compound focus ultrasonic transducer
Assignee: General Electric Co
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Filing: 1986-04-03
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Granted: 1987-04-21
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Expires: 2006-04-03
Abstract
Abstract Improved focussing and increased bandwidth is obtained in a single-element ultrasonic transducer for non-destructive evaluation and material characterization applications. The piezoelectric ceramic element has a radius of curvature R 1 , and a combination lens and cover layer on its front surface has a radius of curvature R 2 which is less than R 1 . The depth of field of the transducer is increased and the bandwidth improved; the total thickness of the lens may be selected to control bandwidth.
Inventors
- 👤 Casmir R. Trzaskos
- 👤 John D. Young
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:34
CPC Classifications
G; G10; G10K; G10K11/00; G10K11/18; G10K11/26; G10K11/30; G10K11/32; H; H04; H04R; H04R2217/00; H04R2217/03
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
136 words
A compound focus C-scan ultrasonic transducer comprising: a single, one-piece piezoelectric ceramic transducer element spherically curved to focus ultrasonic energy and having a radius of curvature R 1 and metallic electrodes on the front and back surface thereof to which electrical leads are connected: a sound absorbing backing bonded to said back surface; and means consisting of an epoxy layer bonded to said front surface that has a radius of curvature R 2 which is less than R 1 and serves as a coveer layer for said transducer, a lens to improve the focusing and result in an increased depth of field, and an impedance matching layer having a thickness at the center between one-quarter wavelength at the preassigned transducer center frequency and up to 20% less than one-quarter wavelength, thereby resulting in an increased bandwidth.
Claim 2
Dependent Claim
136 words
A compound focus C-scan ultrasonic transducer comprising: a single, one-piece piezoelectric ceramic transducer element spherically curved to focus ultrasonic energy and having a radius of curvature R 1 and metallic electrodes on the front and back surface thereof to which electrical leads are connected: a sound absorbing backing bonded to said back surface; and means consisting of an epoxy layer bonded to said front surface that has a radius of curvature R 2 which is less than R 1 and serves as a coveer layer for said transducer, a lens to improve the focusing and result in an increased depth of field, and an impedance matching layer having a thickness at the center between one-quarter wavelength at the preassigned transducer center frequency and up to 20% less than one-quarter wavelength, thereby resulting in an increased bandwidth.
Claim 3
Dependent Claim
21 words
The ultrasonic transudcer of claim 1 wherein said ceramic transducer element is modified sodium niobate and said backing is tungsten-polyvinylchloride composite.
References Cited (Backward Citations)
US4016751A
Cited
US4001766A
Cited
US4184094A
Cited
US4440025A
Cited
US4382201A
Cited
US4445380A
Cited
US4535630A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1990-04-20 | 1990-10-20 | 1991-04-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-04-20 | 1994-10-20 | 1995-04-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-04-20 | 1998-10-20 | 1999-04-21 | $7700.00 | Window Closed / Lapsed |