Patent US3634727A successfully refreshed from Google Patents.
US3634727A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Capacitance-type pressure transducer
Assignee: Bendix Corp
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Filing: 1968-12-03
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Granted: 1972-01-11
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Expires: 1988-12-03
Abstract
Abstract A pressure sensor of the capacitance-type comprising a hollow capsule formed of a pair of discs of single crystal silicon doped to make it electrically conductive and having a layer of silicon dioxide on the surfaces of the discs with portions of the silicon dioxide layer and discs being cut away on opposing faces of the discs to form a cavity therebetween. The discs are insulated from one another and form the plates of a condenser which changes capacity when the sensor is subjected to pressure changes.
Inventors
- 👤 William Ronald Polye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:16
CPC Classifications
G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0072; G01L9/0075; G01L9/0073; G01L9/0082; G01L9/0086
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
39 words
A pressure sensor comprising a hollow capsule having spaced opposing walls formed of single crystal silicon insulated from one another, said walls being movable relative to one another in response to changes in pressure for changing the capacitance therebetween.
Claim 2
Dependent Claim
39 words
A pressure sensor comprising a hollow capsule having spaced opposing walls formed of single crystal silicon insulated from one another, said walls being movable relative to one another in response to changes in pressure for changing the capacitance therebetween.
Claim 3
Dependent Claim
22 words
A pressure sensor as described in claim 1 in which opposing faces of the walls are recessed to form a cavity therebetween.
Claim 4
Dependent Claim
23 words
A pressure sensor as described in claim 1 which is of the capacitance type and the walls form the plates of a capacitor.
Claim 5
Dependent Claim
19 words
A pressure sensor as described in claim 3 having means for connecting the capacitor plates electrically in a circuit.
Claim 6
Dependent Claim
18 words
A pressure sensor as described in claim 3 in which the silicon is doped to make it conductive.
Claim 7
Dependent Claim
23 words
A pressure sensor as described in claim 5 in which the walls are insulated from one another by a layer of silicon dioxide.
Claim 8
Dependent Claim
33 words
A pressure sensor as described in claim 5 in which the walls are insulated from one another by converting mating surfaces of the silicon to a conductivity-type opposite from that of the silicon.
Claim 9
Dependent Claim
60 words
A pressure sensor comprising a pair of discs formed of single crystal silicon doped to make it conductive, means for joining the discs together at their peripheries so that the discs are insulated from one another and form a cavity therebetween, and the discs forming the plates of a condenser which changes capacity upon being subjected to changes in pressure.
Claim 10
Dependent Claim
60 words
A pressure sensor comprising a pair of discs formed of single crystal silicon doped to make it conductive, means for joining the discs together at their peripheries so that the discs are insulated from one another and form a cavity therebetween, and the discs forming the plates of a condenser which changes capacity upon being subjected to changes in pressure.
Claim 11
Dependent Claim
30 words
A pressure sensor as described in claim 8 in which a layer of silicon dioxide is provided on mating surfaces of the discs to insulate the discs from one another.
Claim 12
Dependent Claim
35 words
A pressure sensor as described in claim 8 in which the silicon is converted to opposite conductivity-type at a mating surface of at least one of the discs to insulate the discs from one another.
Claim 13
Dependent Claim
18 words
A pressure sensor as described in claim 8 having means for connecting the condenser plates in a circuit.
Claim 14
Dependent Claim
19 words
A pressure sensor as described in claim 8 in which the discs have recessed portions which form the cavity.
References Cited (Backward Citations)
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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) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |