US3841758A
Expired / Lapsed
US
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Rotation sensitive retarder
Assignee: Individual
•
Filing: 1972-09-28
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Granted: 1974-10-15
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Expires: 1992-09-28
Abstract
Abstract A rotation sensitive retarder system comprising an optical loop around which two linear polarized lightbeams are guided in opposite directions. A splitting and reunifying device is utilized in the optical loop for producing two linear polarized orthogonal components and reunifying the components. Rotation in inertial space produces polarization-form conversion in the reunified beam which then is analyzed to determine the extent of the rotation. A second splitting and reunifying device is provided in combination with the first such that the transmission axes of both are rotated 45* to each other. The second splitting device has a dual purpose, splitting the signal light from the light oscillating in the original plane of the light source light and functioning at the same time as the polarization-form analyzer. The splitting and reunifying device comprises a construction that produces very high efficience. The source of light preferably comprises a laser which is positioned in a manner and the system is provided with means to obviate lock-in, null drift, and results in a very high accuracy at small input rates.
Inventors
- 👤 J Gievers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 16:28
CPC Classifications
G; G01; G01C; G01C19/00; G01C19/58; G01C19/64; G01C19/66; G01C19/68; G01P; G01P3/00; G01P3/36; G01P3/366
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
194 words
A rotation sensitive retarder system comprising means for forming a beam of radiant energy, a first polarizing beamsplitter for splitting said beam into two orthogonal linear polarized components comprising an ordinary ray and an extraordinary ray and for reunifying said components, a plurality of means defining reflective surfaces positioned in a manner such as to provide an optical loop defining identical closed paths for said components of light in opposite directions, said first beamsplitter being positioned in said paths, means in said paths for changing the planes of polarization of the emerging othogonal components by 90* for reunification, a second polarizing beamsplitter positioned exteriorly of said closed paths for transmitting substantially only that part of the reunified light which oscillates in the original plane of zero input rate and directing substantially only the light oscillating in the orthogonal plane due to an input rate externally of the path of the beam and the loop, the transmission axis of one of said beamsplitters being at 45* to the transmission axis of the other beamsplitter, means in advance of the second beamsplitter for modulating the polarization form of the reunified light passing to the second beamsplitter.
Claim 2
Dependent Claim
194 words
A rotation sensitive retarder system comprising means for forming a beam of radiant energy, a first polarizing beamsplitter for splitting said beam into two orthogonal linear polarized components comprising an ordinary ray and an extraordinary ray and for reunifying said components, a plurality of means defining reflective surfaces positioned in a manner such as to provide an optical loop defining identical closed paths for said components of light in opposite directions, said first beamsplitter being positioned in said paths, means in said paths for changing the planes of polarization of the emerging othogonal components by 90* for reunification, a second polarizing beamsplitter positioned exteriorly of said closed paths for transmitting substantially only that part of the reunified light which oscillates in the original plane of zero input rate and directing substantially only the light oscillating in the orthogonal plane due to an input rate externally of the path of the beam and the loop, the transmission axis of one of said beamsplitters being at 45* to the transmission axis of the other beamsplitter, means in advance of the second beamsplitter for modulating the polarization form of the reunified light passing to the second beamsplitter.
Claim 3
Dependent Claim
23 words
The combination as set forth in claim 1 wherein said modulating means comprises means for modulating the path length in the optical loop.
Claim 4
Dependent Claim
27 words
The combination set forth in claim 1 wherein said moudlating means comprises dithering means for angularly vibrating the entire optical circuit about the axis of the system.
Claim 5
Dependent Claim
18 words
The combination set forth in claim 1 wherein said modulating means comprises electrical-optical means for modulating the beam.
Claim 6
Dependent Claim
28 words
The combination set forth in claim 1 wherein said means for changing the planes of polarization of the emerging orthogonal components comprises reflecting surfaces tilted about orthogonal axes.
Claim 7
Dependent Claim
26 words
The combination set forth in claim 1 including a negative feedback means from the output of said second polarizing beamsplitter for compensating for the input rate.
Claim 8
Dependent Claim
24 words
The combination set forth in claim 6 wherein said last-mentioned means comprises a servomotor adapted to provide a feedback rotation for the optical system.
Claim 9
Dependent Claim
23 words
The combination set forth in claim 6 wherein said negative feedback means comprises electro-optical means for providing a feedback input to the beam.
Claim 10
Dependent Claim
19 words
The combination set forth in claim 8 wherein said last-mentioned means comprises a Faraday cell in the optical loop.
Claim 11
Dependent Claim
18 words
The comBination set forth in claim 8 wherein the feedback current is pulsed to provide a digital output.
Claim 12
Dependent Claim
26 words
The combination set forth in claim 1 wherein said means defining said reflective surfaces provide an even number of reflective surfaces in said closed optical path.
Claim 13
Dependent Claim
41 words
The combination set forth in claim 1 wherein the major portion of the path of each closed path is through a solid medium of substantially equal optical density and said reflecting surfaces are provided by total internal reflection in such medium.
Claim 14
Dependent Claim
76 words
The combination set forth in claim 1 wherein said optical loop is utilized as laser cavity, said second beamsplitter externally directs any light which oscillates in the plane orthogonal to the original zero input rate laser oscillation, whereby the oscillating frequency of the two countercirculating light components in the optical loop is kept constant irrespective of the input rate and the light intensity of the output signal is utilized to determine angular rate, thus eliminating lock-in.
Claim 15
Dependent Claim
14 words
The combination set forth in claim 3 wherein said laser comprises a gas laser.
Claim 16
Dependent Claim
15 words
The combination set forth in claim 13 wherein said laser comprises a solid state laser.
Claim 17
Dependent Claim
38 words
The combination set forth in claim 13 wherein said laser beam forming means comprises an amplifying medium positioned externally of said closed optical path and directing the beam through said second polarizing beamsplitter into said closed optical path.
Claim 18
Dependent Claim
22 words
The combination set forth in claim 13 wherein said laser forming means comprises an amplifying medium positioned within the closed optical loop.
Claim 19
Dependent Claim
60 words
The combination set forth in claim 13 wherein the laser comprises an amplifying medium and one end reflector, said amplifying medium and said end reflector being located in the combined beam outside the optical loop, the resonance cavity of said laser comprising the path from the end reflector around the optical loop and back in order to eliminate null drift.
Claim 20
Dependent Claim
27 words
The combination set forth in claim 13 wherein said modulating means comprises dithering means for angularly vibrating the entire optical circuit about the axis of the system.
Claim 21
Dependent Claim
18 words
The combination set forth in claim 13 wherein said modulating means comprises electrical-optical means for modulating the beam.
Claim 22
Dependent Claim
28 words
The combination set forth in claim 13 wherein said means for changing the planes of polarization of the emerging orthogonal components comprises reflecting surfaces tilted about orthogonal axes.
Claim 23
Dependent Claim
26 words
The combination set forth in claim 13 including a negative feedback means from the output of said second polarizing beamsplitter for compensating for the input rate.
Claim 24
Dependent Claim
24 words
The combination set forth in claim 21 wherein said last-mentioned means comprises a servomotor adapted to provide a feedback rotation for the optical system.
Claim 25
Dependent Claim
23 words
The combination set forth in claim 21 wherein said negative feedback means comprises electro-optical means for providing a feedback input to the beam.
Claim 26
Dependent Claim
18 words
The combination set forth in claim 24 wherein the feedback current is pulsed to provide a digital output.
Claim 27
Dependent Claim
26 words
The combination set forth in claim 13 wherein said means defining said reflective surfaces provide an even number of reflective surfaces in said closed optical path.
Claim 28
Dependent Claim
41 words
The combination set forth in claim 13 wherein the major portion of the path of each closed path is through a solid medium of substantially equal optical density and said reflecting surfaces are provided by total internal reflection in such medium.
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) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |