US3790284A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Interferometer system for measuring straightness and roll
Assignee: HP Inc
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Filing: 1972-05-08
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Granted: 1974-02-05
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Expires: 1992-05-08
Abstract
Abstract An interferometer system for measuring straightness including a light source for producing a beam of light, preferably a two frequency laser with the two frequency components linearly polarized and orthogonal to one another, the light beam being directed through a Wollaston prism where the beam is split into two separate paths which deviate, in opposite paths, from the original beam direction by a small angle. The two separate beams are transmitted over two separate paths to associated ones of two separate reflective surfaces which are mounted in a mutually fixed relationship and at an angle to each other. The two beams are reflected back into the prism from the associated reflective surfaces where they are recombined. Photodetector means are provided for detecting any changes in the fringes resulting from a change in one optical path length relative to other optical path length as the two mirrors move relative to the prism, said change in path lengths resulting from deviations from straightness in such movement. A dual system is disclosed for measuring rotational motion, i.e., roll.
Inventors
- 👤 R Baldwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:00
CPC Classifications
G; G01; G01B; G01B9/00; G01B9/02; G01B9/02015; G01B9/02017; G01B9/02019; G01B9/02001; G01B9/02007; G01B2290/00; G01B2290/45; G01B2290/70
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
210 words
An interferometric system comprising: a light source for producing a principal light beam along a principal axis; beam splitting means positioned in the path of the principal light beam for splitting the principal light beam into first and second associated light beams and deviating the first and second associated light beams from the direction of the principal light beam by equal and opposite angular deviations; first and second plane reflecting surfaces positioned in the paths of the first and second associated light beams, respectively, these two plane reflecting surfaces being fixedly positioned relative to each other at a non-zero angle bisected by the principal axis, the first associated light beam being reflected back to the beam splitting means by the first plane reflecting surface, and the second associated light beam being reflected back to the beam splitting means by the second plane reflecting surface, the two beams recombining at the beam splitting means to form a first set of optical interference fringes responsive to motion of the first and second plane reflecting surfaces transverse to the principal axis; and detection means for detecting the first set of optical interference fringes to produce an output indicative of gotion of the first and second plane reflecting surfaces transverse to the principal axis.
Claim 2
Dependent Claim
210 words
An interferometric system comprising: a light source for producing a principal light beam along a principal axis; beam splitting means positioned in the path of the principal light beam for splitting the principal light beam into first and second associated light beams and deviating the first and second associated light beams from the direction of the principal light beam by equal and opposite angular deviations; first and second plane reflecting surfaces positioned in the paths of the first and second associated light beams, respectively, these two plane reflecting surfaces being fixedly positioned relative to each other at a non-zero angle bisected by the principal axis, the first associated light beam being reflected back to the beam splitting means by the first plane reflecting surface, and the second associated light beam being reflected back to the beam splitting means by the second plane reflecting surface, the two beams recombining at the beam splitting means to form a first set of optical interference fringes responsive to motion of the first and second plane reflecting surfaces transverse to the principal axis; and detection means for detecting the first set of optical interference fringes to produce an output indicative of gotion of the first and second plane reflecting surfaces transverse to the principal axis.
Claim 3
Dependent Claim
18 words
An interferometric system as in claim 1 wherein each of the plane reflecting surfaces comprises a plane mirror.
Claim 4
Dependent Claim
16 words
An interferometric system as in claim 2 wherein the beam splitting means includes a Wollaston prism.
Claim 5
Dependent Claim
215 words
An interferometric system as in claim 1 wherein: the beam splitting means is adapted to additionally split the principal light beam into third and fourth associated light beams and deviate the third and fourth associated light beams from the direction of the principal light beam by equal and opposite angular deviations; third and fourth plane reflecting surfaces are positioned in the paths of the third and fourth associated light beams, respectively, and are fixedly positioned relative to each other at a non-zero angle bisected by the principal axis and fixedly positioned relative to the first and second plane reflecting surfaces, the third and fourth associated light beams being reflected back to the beam splitting means by the third and fourth plane reflecting surfaces, respectively, the third and fourth associated light beams recombining at the beam splitting means to form a second set of optical interference fringes responsive to motion of the third and fourth plane reflecting surfaces transverse to the principal axis; and means are included for detecting the second set of optical interference fringes and determining the difference, if any, between the first set of optical interference fringes and the second set of optical interference fringes to produce an output indicative of roll motion of the first through fourth mirrors around the principal axis.
Claim 6
Dependent Claim
20 words
An interferometric system as in claim 4 wherein the third and fourth plane reflecting surfaces each comprise a plane mirror.
Claim 7
Dependent Claim
40 words
An interferometric system as in claim 5 wherein the beam splitTing means includes a first Wollaston prism for deviating the first and second associated light beams and a second Wollaston prism for deviating the third and fourth associated light beams.
Claim 8
Dependent Claim
54 words
An interferometric system as in claim 1 wherein: the principal light beam is a two-frequency beam; and the beam splitting means splits the principal light beam into a first associated light beam of a first frequency and a first polarization and a second associated light beam of a second frequency and a second polarization.
Claim 9
Dependent Claim
50 words
An interferometric system as in claim 4 wherein: the principal light beam is a two-frequency beam; and the first and third associated light beams are of a first frequency and a first polarization, and the second and fourth associated light beams are of a second frequency and a second polarization.
Claim 10
Dependent Claim
37 words
An interferometric system as in claim 4 wherein the third plane reflecting surface comprises a portion of the first plane reflecting surface and the fourth plane reflecting surface comprises a portion of the second plane reflecting surface.
References Cited (Backward Citations)
US3523735A
Cited
US3458259A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |