Patent US3736436A successfully refreshed from Google Patents.
US3736436A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electret pressure transducer
Assignee: McDonnell Douglas Corp
•
Filing: 1971-11-04
•
Granted: 1973-05-29
•
Expires: 1991-11-04
Abstract
Abstract An electret pressure transducer consisting of a very thin insulating coating applied to the surface of a body to be investigated when under stress, a thin layer of conductive paint or metallic deposit configured to extend over the area to be investigated, a layer of a solid elastic material, the electretfilm containing a permanent electric charge, and a metallic deposit on the electret film. The layer of conductive paint and the metallic deposit constitute the two plates of a parallelplate capacitor, and the elastic material in conjunction with the electric charge provided by the electret determines the sensitivity, linearity, and frequency response of the transducer.
Inventors
- 👤 R Crites
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:21
CPC Classifications
H; H04; H04R; H04R19/00; H04R19/01
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
32 words
The transducer set forth in claim 1 wherein said electret film, substrate and conductive layers are flexible and capable of conforming to the shape of a body under investigation for applied pressure.
Claim 2
Dependent Claim
23 words
The transducer set forth in claim 1 wherein said conductive layers are applied conductive films, having a combined thickness of about one mil.
Claim 3
Dependent Claim
23 words
The transducer set forth in claim 1 wherein said film, substrate and layers have a substantially coextensive area and are in intimate contact.
Claim 4
Dependent Claim
109 words
As an article of manufacture in the form of an electret pressure transducer body for placement on an imperforate surface to be investigated for applied surface pressure, said body being subject to the applied pressure and consisting at least of two electrically conductive imperforate and flexible layers and an intervening layer of a compliant imperforate material, said compliant layer containing an electric charge and responding to applied pressure to change the capacitance of said article as a function of the response of said compliant layer to pressure applied on the surface to be investigated, and said electrically conductive layers and said compliant layer being in surface to surface contact.
Claim 5
Dependent Claim
29 words
As an article of manufacture set forth in claim 5, the electret pressure transducer thereof in which the plurality of layers in stacked engagement include an electrical insulating coating.
Claim 6
Dependent Claim
29 words
The article of manufacture set forth in claim 5 wherein said electret pressure transducer body is flexible and conformable to the configuration of the surface area to be investigated.
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) | 1976-05-28 | 1976-11-27 | 1977-05-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-05-28 | 1980-11-27 | 1981-05-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-05-28 | 1984-11-27 | 1985-05-29 | $7700.00 | Window Closed / Lapsed |