Patent US3671784A successfully refreshed from Google Patents.
US3671784A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Piezo-electric transducers having variable sensitivity between the boundaries of the piezo-electric crystal
Assignee: US Philips Corp
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Filing: 1970-07-23
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Granted: 1972-06-20
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Expires: 1990-07-23
Abstract
Abstract An acoustical transducer having an improved electrical impedance at the lower end of the useful acoustical passband comprises a body of material in which a stress is produced by the application of a magnetic or electrical field. The body of material has a first boundary substantially free of acoustical boundary, a second boundary acoustically matched to an acoustic wave transmission media and means for producing an electrical field stress in the material which will propagate from the first boundary to the second boundary with the stress decreasing in a substantially continuous manner along the propagation direction.
Inventors
- 👤 Richard Frank Mitchell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:32
CPC Classifications
H; H04; H04R; H04R17/00; H04R15/00; Y; Y10; Y10T; Y10T29/00; Y10T29/42
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
An acoustic transducer comprising a body having opposing boundary faces, said body comprising a material having a variation in piezo-electric coupling constant between said boundary faces, and means for eliminating an acoustic resonance within the passband of the transducer; said means comprising means for producing an electric field in said material, said electric field resulting in a piezo-electric stress amplitude variation in said material substantially in accordance with where d is the distance between said boundary faces and x is the distance from one of said boundary faces to a point within said material.
Claim 2
Dependent Claim
94 words
An acoustic transducer comprising a body having opposing boundary faces, said body comprising a material having a variation in piezo-electric coupling constant between said boundary faces, and means for eliminating an acoustic resonance within the passband of the transducer; said means comprising means for producing an electric field in said material, said electric field resulting in a piezo-electric stress amplitude variation in said material substantially in accordance with where d is the distance between said boundary faces and x is the distance from one of said boundary faces to a point within said material.
Claim 3
Dependent Claim
47 words
An acoustic transducer as claimed in claim 1 wherein said piezo-electric coupling constant has an amplitude variation substantially in accordance with where d is the distance between said boundary faces and x is the distance from one of said boundary faces to a point within said material.
Claim 4
Dependent Claim
25 words
An acoustic transducer as claimed in claim 2 wherein said means for producing an electric field produces a substantially uniform electric field within said material.
Claim 5
Dependent Claim
51 words
An acoustic transducer comprising a body having opposing boundary faces, said body comprising a material having a variation in piezo-magnetic coupling constant between said boundary faces, and means for eliminating an acoustic resonance within the passband of the transducer; said means comprising means for producing a magnetic field in said material.
Claim 6
Dependent Claim
51 words
An acoustic transducer comprising a body having opposing boundary faces, said body comprising a material having a variation in piezo-magnetic coupling constant between said boundary faces, and means for eliminating an acoustic resonance within the passband of the transducer; said means comprising means for producing a magnetic field in said material.
Claim 7
Dependent Claim
56 words
An acoustic transducer as claimed in claim 4 wherein said means for producing a magnetic field results in a piezo-magnetic stress amplitude variation in said material substantially in accordance with where d is the distance between said boundary faces and x is the distance from one of said boundary faces to a point within said material.
Claim 8
Dependent Claim
47 words
An acoustic transducer as claimed in claim 5 wherein said piezo-magnetic coupling constant has an amplitudE variation substantially in accordance with where d is the distance between said boundary faces and x is the distance from one of said boundary faces to a point within said material.
Claim 9
Dependent Claim
25 words
An acoustic transducer as claimed in claim 6 wherein said means for producing a magnetic field produces a substantially uniform magnetic field within said material.
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) | 1975-06-20 | 1975-12-20 | 1976-06-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-06-20 | 1979-12-20 | 1980-06-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-06-20 | 1983-12-20 | 1984-06-20 | $7700.00 | Window Closed / Lapsed |