US3738753A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Interferometer utilizing gratings to measure motion
Assignee: HOLOGRAF CORP
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Filing: 1970-09-21
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Granted: 1973-06-12
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Expires: 1990-09-21
Abstract
Abstract An interferometer and method of making same are disclosed wherein two energetic beams are used to record an interference pattern to form a grating having a period of a substantially exact multiple or standard submultiple of a standard measuring unit and wherein this interference pattern is utilized in an interferometer fringe counter wherein relative movement of the grating and source produce a fringe count which is a measure of the relative movement. The grating is disclosed as a hologram, and in one embodiment light is transmitted through the hologram in one direction and then back through the hologram in another direction whereby the interference fringes are established on the same side of the hologram as the source. In another embodiment two holograms are utilized, one fixed and one movable relative to the source, and interference fringes are established on the side of the hologram opposite the side where the source is located.
Inventors
- 👤 W Huntley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:41
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/32; G01; G01B; G01B9/00; G01B9/02; G01B9/02055; G01B9/02075; G01B9/02078; G01B9/02079; G01B9/02081; G01B2290/00; G01B2290/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
153 words
An interferometer comprising: a fourier-transform hologram formed from the interference pattern of two energetic beams, an energetic source positioned on one side of the said hologram to direct an energetic beam onto said hologram, means on the other side of said hologram from said source for redirecting zero order mode source energy passed by said hologram back to said hologram for passage therethrough and separation of first order mode energy portion thereof, means on said other side of said hologram for redirecting first order mode source energy passed by said hologram back to said hologram for passage therethough and formation of an interference pattern with said first order mode energy portion of said redirected zero order mode energy, means for providing relative movement between said hologram and said source for movement of said interference pattern, and means for detecting said interference pattern and counting the fringes of said pattern during said relative movement.
Claim 2
Dependent Claim
153 words
An interferometer comprising: a fourier-transform hologram formed from the interference pattern of two energetic beams, an energetic source positioned on one side of the said hologram to direct an energetic beam onto said hologram, means on the other side of said hologram from said source for redirecting zero order mode source energy passed by said hologram back to said hologram for passage therethrough and separation of first order mode energy portion thereof, means on said other side of said hologram for redirecting first order mode source energy passed by said hologram back to said hologram for passage therethough and formation of an interference pattern with said first order mode energy portion of said redirected zero order mode energy, means for providing relative movement between said hologram and said source for movement of said interference pattern, and means for detecting said interference pattern and counting the fringes of said pattern during said relative movement.
Claim 3
Dependent Claim
140 words
An interferometric fringe counter, comprising: a diffraction grating, an energetic source positioned to direct an energy beam to said grating to form an undiffracted zero order beam and at least one diffracted order beam. means positioned in the path of said undiffracted zero order beam for redirecting said zero order beam to said grating, thereby diffracting a portion of said zero order beam into a second diffracted order beam, means for redirecting said at least one diffracted order beam to combine with said second diffracted order beam, whereby interference fringes are formed in the combined diffracted order beams, means for providing relative movement between said source and said grating in a direction substantially perpendicular to the fringes of said interference pattern, means for detecting said interference fringes; and means for counting said fringes as a measure of said relative movement.
Claim 4
Dependent Claim
140 words
An interferometric fringe counter, comprising: a diffraction grating, an energetic source positioned to direct an energy beam to said grating to form an undiffracted zero order beam and at least one diffracted order beam. means positioned in the path of said undiffracted zero order beam for redirecting said zero order beam to said grating, thereby diffracting a portion of said zero order beam into a second diffracted order beam, means for redirecting said at least one diffracted order beam to combine with said second diffracted order beam, whereby interference fringes are formed in the combined diffracted order beams, means for providing relative movement between said source and said grating in a direction substantially perpendicular to the fringes of said interference pattern, means for detecting said interference fringes; and means for counting said fringes as a measure of said relative movement.
Claim 5
Dependent Claim
43 words
An interferometric fringe counter of claim 2 wherein said grating is a transmission type grating, said energetic source and said detecting means are positioned on one side of the grating, and said redirecting means are positioned on an opposite side of the grating.
Claim 6
Dependent Claim
165 words
An interferometer, comprising: means for generating an electromagnetic energy illuminating beam having spatial coherence in at least one direction, a pair of closely-spaced parallel line gratings positioned in the path of said illuminating beam, said gratings having their lines substantially parallel to each other but perpendicular to said one direction, a first grating thereby passing a portion of said energy directly through as a zero order beam and diffracting a portion into a first or higher order beam, a second grating diffracting a portion of said zero order beam into a first or higher order beam propagating in substantially the same direction as said beam diffracted by the first grating, thereby generating fringes of interference across said diffracted beams, means for providing relative motion between said pair of gratings, and means fixed with respect to said illuminating beam in the path of said first or higher order diffracted beams for detecting movement of said fringes as relative motion is applied to the pair of gratings.
Claim 7
Dependent Claim
165 words
An interferometer, comprising: means for generating an electromagnetic energy illuminating beam having spatial coherence in at least one direction, a pair of closely-spaced parallel line gratings positioned in the path of said illuminating beam, said gratings having their lines substantially parallel to each other but perpendicular to said one direction, a first grating thereby passing a portion of said energy directly through as a zero order beam and diffracting a portion into a first or higher order beam, a second grating diffracting a portion of said zero order beam into a first or higher order beam propagating in substantially the same direction as said beam diffracted by the first grating, thereby generating fringes of interference across said diffracted beams, means for providing relative motion between said pair of gratings, and means fixed with respect to said illuminating beam in the path of said first or higher order diffracted beams for detecting movement of said fringes as relative motion is applied to the pair of gratings.
Claim 8
Dependent Claim
25 words
The interferometer of claim 4 wherein each of said pair of gratings is a holographic grating formed from an interference of two coherent energy beams.
Claim 9
Dependent Claim
176 words
An interferometer, comprising: means for generating a polychromatic electromagnetic energy illuminating beam having spatial coherence in at least one direction, a pair of closely spaced parallel line gratings positioned in the path of said illuminating beam, said gratings having their lines substantially parallel to each other but perpendicular to said one direction, a first grating thereby passing a portion of said energy through as a zero order beam and diffracting a portion into a first or higher order beam, a second grating diffracting a portion of said zero order beam into a first or higher order beam propagating in substantially the same direction as said beam diffracted by the first grating, thereby generating sharp achromatic fringes of interference in a plane through said diffracted beams, means for providing relative motion between said pair of gratings, and means fixed with respect to said illuminating beam in the path of said first or higher order diffracted beams at said achromatic fringe plane for detecting movement of said fringes as relative motion is applied to the pair of gratings.
Claim 10
Dependent Claim
176 words
An interferometer, comprising: means for generating a polychromatic electromagnetic energy illuminating beam having spatial coherence in at least one direction, a pair of closely spaced parallel line gratings positioned in the path of said illuminating beam, said gratings having their lines substantially parallel to each other but perpendicular to said one direction, a first grating thereby passing a portion of said energy through as a zero order beam and diffracting a portion into a first or higher order beam, a second grating diffracting a portion of said zero order beam into a first or higher order beam propagating in substantially the same direction as said beam diffracted by the first grating, thereby generating sharp achromatic fringes of interference in a plane through said diffracted beams, means for providing relative motion between said pair of gratings, and means fixed with respect to said illuminating beam in the path of said first or higher order diffracted beams at said achromatic fringe plane for detecting movement of said fringes as relative motion is applied to the pair of gratings.
Claim 11
Dependent Claim
27 words
The interferometer of claim 6 wherein the period of each of the pair of gratings is substantially an exact multiple or submultiple of a standard measuring unit.
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) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |