Patent US5146083A successfully refreshed from Google Patents.
US5146083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High temperature fiber optic microphone having a pressure-sensing reflective membrane under tensile stress
Assignee: National Aeronautics and Space Administration
•
Filing: 1990-09-21
•
Granted: 1992-09-08
•
Expires: 2010-09-21
Abstract
Abstract A fiber optic microphone is provided for measuring fluctuating pressures. An optical fiber probe having at least one transmitting fiber for transmitting light to a pressure-sensing membrane and at least one receiving fiber for receiving light reflected from a stretched membrane is provided. The pressure-sensing membrane may be stretched for high frequency response. Further, a reflecting surface of the pressure-sensing membrane may have dimensions which substantially correspond to dimensions of a cross section of the optical fiber probe. Further, the fiber optic microphone can be made of materials for use in high temperature environments, for example greater than 1000 DEG F. A fiber optic probe is also provided with a backplate for damping membrane motion. The backplate further provides a means for on-line calibration of the microphone.
Inventors
- 👤 Allan J. Zuckerwar
- 👤 Frank W. Cuomo
- 👤 William E. Robbins
- 👤 Purnell Hopson, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 11:38
CPC Classifications
H; H04; H04R; H04R23/00; H04R23/008; G; G01; G01L; G01L9/00; G01L9/0041; G01L9/0076; G01L9/0077; G02; G02B; G02B6/00; G02B6/44; G02B6/4401; G02B6/4415; G02B6/4427; G02B6/4428; G02B6/24; G02B6/36; G02B6/3616; G02B6/3624; G02B6/38; G02B6/3807; G02B6/381; G02B6/3817
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
125 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light; a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to the pressure fluctuations to be measured, said membrane is under tensile stress while at rest, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by center displacement of the membrane is indicative of the sound pressure incident on the membrane.
Claim 2
Independent Claim
125 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light; a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to the pressure fluctuations to be measured, said membrane is under tensile stress while at rest, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by center displacement of the membrane is indicative of the sound pressure incident on the membrane.
Claim 3
Dependent Claim
29 words
The apparatus of claim 1, wherein an active area of the reflecting surface has dimensions which substantially correspond to dimensions of a cross section of the optical fiber probe
Claim 4
Independent Claim
16 words
The apparatus of claim I, said apparatus having a frequency response of at least 100 kHz
Claim 5
Dependent Claim
15 words
The apparatus of claim 1, further comprising a tension adjuster for adjusting said tensile stress.
Claim 6
Dependent Claim
41 words
The apparatus of claim 1, further comprising an adjustable tension ring for supporting and applying said tensile stress to said membrane, said tension ring being provided with an axial hole having dimensions which substantially correspond to dimensions of said reflecting surface.
Claim 7
Independent Claim
27 words
The apparatus of claim wherein said membrane is stretched over a convex surface having an opening therein for allowing said transmitted and reflected light to pass therethrough.
Claim 8
Dependent Claim
12 words
The apparatus of claim 6, wherein said convex surface is substantially hemispherical.
Claim 9
Dependent Claim
20 words
The apparatus of claim 1, wherein said optical fiber probe is at least partly encased in a heat resistant sheath.
Claim 10
Dependent Claim
18 words
The apparatus of claim 8, wherein said optical fiber probe is resistant to temperatures higher than 1000° F.
Claim 11
Dependent Claim
35 words
The apparatus of claim 8, wherein said sheath comprises a rigid tube encasing part of said optical fiber probe proximate to said membrane, and a flexible tube encasing another part of said optical fiber probe.
Claim 12
Dependent Claim
13 words
The apparatus of claim 10, wherein said flexible tube overlaps said rigid tube.
Claim 13
Dependent Claim
28 words
The apparatus of claim 8, further comprising a high temperature resistant bonding agent for holding said optical fibers within at least part of said sheath proximate said membrane.
Claim 14
Dependent Claim
30 words
The apparatus of claim 1, further comprising a backplate adjacent said membrane of the same side of said membrane as said optical fiber probe, said backplate having an axial opening.
Claim 15
Dependent Claim
17 words
The apparatus of claim 13, wherein said backplate has a damping effect on vibrations of said membrane.
Claim 16
Dependent Claim
30 words
The apparatus of claim 13, further comprising a voltage source connected to said backplate and said membrane which can create a known voltage potential between said backplate and said membrane.
Claim 17
Independent Claim
143 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light to a light receiver; and a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to pressure fluctuations to be measured, and an active area of the reflecting surface has dimensions which substantially correspond to dimensions of a cross-section of the optical fiber probe, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by center displacement of the microphone is indicative of the sound pressure incident on the membrane.
Claim 18
Independent Claim
143 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light to a light receiver; and a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to pressure fluctuations to be measured, and an active area of the reflecting surface has dimensions which substantially correspond to dimensions of a cross-section of the optical fiber probe, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by center displacement of the microphone is indicative of the sound pressure incident on the membrane.
Claim 19
Dependent Claim
23 words
The apparatus of claim 16, wherein said active area and said cross section are each substantially circular and have substantially the same diameter.
Claim 20
Dependent Claim
19 words
The apparatus of claim 16, wherein said optical fiber probe has a temperature resistance of at least 1000° F.
Claim 21
Dependent Claim
24 words
The apparatus of claim 16, wherein at least a part of said optical fiber probe proximate said membrane is encased in hypodermic needle tubing.
Claim 22
Dependent Claim
15 words
The apparatus of claim 16, wherein said membrane is under tensile stress while at rest.
Claim 23
Dependent Claim
18 words
The apparatus of claim 20, wherein said optical fiber has a frequency response of at least 100 kHz.
Claim 24
Dependent Claim
25 words
The apparatus of claim 20, wherein said membrane is stretched over a convex tension ring provided with an axial opening which defines said active area.
Claim 25
Dependent Claim
13 words
The apparatus of claim 22, wherein said convex tension ring is substantially hemispherical.
Claim 26
Independent Claim
166 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light to a light receiver, a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to pressure fluctuations to be measured, wherein said membrane is under tensile stress while at rest, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by the center displacement of the membrane is indicative of the sound pressure incident on the membrane; and a pin-vise assembly for securing the optical fiber probe such that a constant gap is provided between an end of the optical fiber probe and said reflecting surface when said reflecting surface is at rest.
Claim 27
Independent Claim
166 words
An apparatus for measuring pressure fluctuations, comprising: an optical fiber probe comprising a single optical fiber for transmitting light from a light source and a plurality of optical fibers for receiving and transmitting reflected light to a light receiver, a pressure-sensing membrane having a reflecting surface for reflecting said light, wherein said reflecting surface undergoes deflections in relation to pressure fluctuations to be measured, wherein said membrane is under tensile stress while at rest, wherein said optical fiber probe is arranged such that said single optic fiber transmits light to the approximate center of the reflecting surface and the plurality of optical fibers receives and transmits the reflected light, whereby the light reflected by the center displacement of the membrane is indicative of the sound pressure incident on the membrane; and a pin-vise assembly for securing the optical fiber probe such that a constant gap is provided between an end of the optical fiber probe and said reflecting surface when said reflecting surface is at rest.
References Cited (Backward Citations)
US3580082A
Cited
US3789667A
Cited
US3831137A
Cited
US3940608A
Cited
US3903497A
Cited
US4098031A
Cited
US4158310A
Cited
US4149423A
Cited
US4210029A
Cited
US4446543A
Cited
US4329017A
Cited
US4286468A
Cited
US4258508A
Cited
US4354735A
Cited
US4310905A
Cited
US4473747A
Cited
US4363115A
Cited
US4550975A
Cited
US4512113A
Cited
US4547668A
Cited
US4599711A
Cited
US4687927A
Cited
US4926696A
Cited
US4932263A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |