Patent US3625616A successfully refreshed from Google Patents.
US3625616A
Expired / Lapsed
US
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Interferometric pressure sensor
Assignee: Bendix Corp
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Filing: 1969-06-25
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Granted: 1971-12-07
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Expires: 1989-06-25
Abstract
Abstract A pressure sensor having two chambers each filled to a predetermined pressure with a gas of high-refractive index and sealed. To measure pressure the gas in one chamber is subjected to the pressures to be measured by changing the volume of the chamber by a bellows. A beam of coherent light is split and passed through the two chambers and then recombined. A fringe counter detects fringe shifts caused by differences in the optical paths due to differences between the measured and predetermined pressures and provides a signal corresponding thereto. To measure differential pressure the gas in both chambers is subjected to the pressures to be measured.
Inventors
- 👤 Walter W Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 17:18
CPC Classifications
G; G01; G01L; G01L11/00; G01L11/02
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
156 words
An interferometric pressure sensor for measuring pressure, comprising: first and second chambers each containing a gas of high refractive index and each being sealed at a predetermined pressure, at least one of said chambers having means for applying the pressure to be measured to the chamber to change the pressure in the chamber to correspond to the pressure to be measured; a light source providing a beam of coherent light; beam splitter proximate one end of each of said chambers means for splitting the light beam into two beams and for passing the one beam through the first chamber and the other beam through the second chamber reflective means proximate the opposite end of said chambers for reflecting said beams back to said beam splitter for recombining the beams into a beam having interference fringes which shift in accordance with a difference between the pressures in the chambers; and photoresponsive means for detecting the fringe shift.
Claim 2
Dependent Claim
156 words
An interferometric pressure sensor for measuring pressure, comprising: first and second chambers each containing a gas of high refractive index and each being sealed at a predetermined pressure, at least one of said chambers having means for applying the pressure to be measured to the chamber to change the pressure in the chamber to correspond to the pressure to be measured; a light source providing a beam of coherent light; beam splitter proximate one end of each of said chambers means for splitting the light beam into two beams and for passing the one beam through the first chamber and the other beam through the second chamber reflective means proximate the opposite end of said chambers for reflecting said beams back to said beam splitter for recombining the beams into a beam having interference fringes which shift in accordance with a difference between the pressures in the chambers; and photoresponsive means for detecting the fringe shift.
Claim 3
Dependent Claim
54 words
A pressure sensor of the kind described in claim 1 for measuring the difference between two pressures in which both of said chambers have means for applying the pressures to the chambeRs so that the pressures in the chambers correspond to the two pressures, the fringe shift corresponding to the difference between the pressures.
Claim 4
Dependent Claim
23 words
A pressure sensor as described in claim 1, in which the first means includes a bellows for changing the volume of the chamber.
Claim 5
Dependent Claim
30 words
A pressure sensor as described in claim 1, in which the gas of high-refractive index is selected from the group consisting of octane, dodecane, carbon disulfide, carbon tetrachloride and trichlorofluromethane.
Claim 6
Dependent Claim
25 words
A pressure sensor as described in claim 1, in which the light source provides a beam of coherent light having a relatively long coherence length.
Claim 7
Dependent Claim
17 words
A pressure sensor as described in claim 1, in which the light source comprises a laser device.
Claim 8
Dependent Claim
28 words
A pressure sensor as described in claim 1, in which the photoresponsive means comprises a photodetector and fringe counter for providing a signal corresponding to the fringe shift.
Claim 9
Dependent Claim
30 words
A pressure sensor as described in claim 2, in which the gas of high-refractive index is selected from the group consisting of octane, dodecane, carbon disulfide carbon tetrachloride and trichlorofluromethane.
Claim 10
Dependent Claim
150 words
An interferometric pressure sensor for measuring pressure, comprising: two chambers each containing gas of high-refractive index and sealed at predetermined pressure, at least one of said chambers including means for applying the pressure to be measured to the chamber to subject the gas in the chamber to the pressure to be measured; a laser device providing a beam of coherent light having a relatively long coherence length; beam splitter means proximate one end of said chambers for splitting the light beam into two beams and for passing the one beam through one chamber and the other beam through the other chamber reflective means proximate the opposite end of said chambers for reflecting said light beams back to said beam splitter means, for recombining the beams into a beam having interference fringes which shift in accordance with the pressure; and photoresponsive means receiving said recombined beams for detecting the fringe shift.
Claim 11
Dependent Claim
150 words
An interferometric pressure sensor for measuring pressure, comprising: two chambers each containing gas of high-refractive index and sealed at predetermined pressure, at least one of said chambers including means for applying the pressure to be measured to the chamber to subject the gas in the chamber to the pressure to be measured; a laser device providing a beam of coherent light having a relatively long coherence length; beam splitter means proximate one end of said chambers for splitting the light beam into two beams and for passing the one beam through one chamber and the other beam through the other chamber reflective means proximate the opposite end of said chambers for reflecting said light beams back to said beam splitter means, for recombining the beams into a beam having interference fringes which shift in accordance with the pressure; and photoresponsive means receiving said recombined beams for detecting the fringe shift.
Claim 12
Dependent Claim
53 words
A pressure sensor of the kind described in claim 12 for measuring the difference between two pressures in which both chambers have means for applying the pressures to the chambers to change the pressures in the chambers to correspond to the two pressures, the fringe shift corresponding to the difference between the pressures.
Claim 13
Dependent Claim
17 words
A pressure sensor as described in claim 2, in which the light source comprises a laser device.
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) | 1974-12-06 | 1975-06-07 | 1975-12-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-06 | 1979-06-07 | 1979-12-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-06 | 1983-06-07 | 1983-12-07 | $7700.00 | Window Closed / Lapsed |