US3770340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Coherent optical system with expanded bandwidth and noise suppression
Assignee: Technical Operations Inc
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Filing: 1972-08-21
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Granted: 1973-11-06
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Expires: 1992-08-21
Abstract
Abstract A coherent optical system is shown having the principal optical components arrayed on an axis, with a coherent light source effectively located off axis and arranged for effective rotation in a circular locus concentric with the axis. The dc term of the Fourier transform of an object that modulates light from the source is located off-axis in the Fourier transform plane and rotates about the axis so that an aperture stop in the transform plane which would pass the n-th order diffraction pattern where the dc term located on axis now passes the 2n-th order diffraction pattern thereby doubling the spatial frequency bandwidth of such coherent systems and enhancing resolution. At the same time, optical noise is reduced by averaging over the field.
Inventors
- 👤 D Cronin
- 👤 A Pinard
- 👤 A Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:30
CPC Classifications
G; G02; G02B; G02B27/00; G02B27/42; G02B27/4266
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
87 words
Method of operating a coherent optical system having its principal optical components arrayed on a given axis, to minimize noise and increase the spatial frequency bandwidth, comprising the steps of erecting a source of coherent light effectively displaced transversely from said axis, focusing an image of said source in a Fourier transform plane at a locus in said plane displaced transversely from said axis, and effectively rotating said source around said axis on a fixed radius, whereby to rotate said image in said plane on afixed radius.
Claim 2
Dependent Claim
87 words
Method of operating a coherent optical system having its principal optical components arrayed on a given axis, to minimize noise and increase the spatial frequency bandwidth, comprising the steps of erecting a source of coherent light effectively displaced transversely from said axis, focusing an image of said source in a Fourier transform plane at a locus in said plane displaced transversely from said axis, and effectively rotating said source around said axis on a fixed radius, whereby to rotate said image in said plane on afixed radius.
Claim 3
Dependent Claim
57 words
Method according to claim 1 in which the Fourier transform of an obJect modulating light from said source is formed in said Fourier transform plane, comprising the step of locating the dc term of said Fourier transform substantially entirely to one side of said axis whereby rotation of said source rotates said dc term about said axis.
Claim 4
Dependent Claim
14 words
Method according to claim 2 comprising the step of substantially blocking said dc term.
Claim 5
Dependent Claim
24 words
Method according to claim 2 comprising the step of phase-shifting said dc term substantially pi /2 relative to the remainder of said Fourier transform.
Claim 6
Dependent Claim
21 words
Method according to claim 2 comprising spatially-filtering said Fourier transform with a filter that is fixed relative to said Fourier transform.
Claim 7
Dependent Claim
100 words
Method according to claim 1 in which the Fourier transform of an object modulating light from said source is formed in said Fourier transform plane, said plane having a predetermined entrance pupil, said Fourier transform including spatial frequency components of which the n-th component would be the highest passed through said entrance pupil if said dc term were centered on said axis, comprising the step of locating said dc term substantially at the edge of said entrance pupil so that during said rotation of said source the 2n-th component of said spatial frequency components is passed through said entrance pupil.
Claim 8
Dependent Claim
35 words
Method according to claim 1 comprising the step of locating a real source of said light on a circular locus at a fixed transverse distance from said axis, and rotating said source in said locus.
Claim 9
Dependent Claim
63 words
Method according to claim 1 comprising the steps of locating a real source of said light on said axis, optically effectively displacing light from said source to a region transversely disposed to said axis and thereby erecting a virtual source of said light on a circular locus at a fixed transverse distance from said axis, and rotating said virtual source in said locus.
Claim 10
Dependent Claim
108 words
In a coherent optical system for forming in a Fourier transform plane having a predetermined entrance pupil, from coherent illumination, a Fourier transform object located to modulate said illumination, said transform having a dc term and a series of spatial frequency components, the improvement comprising a source of coherent light appearing to be spaced transversely from said axis in a circular locus centered on said axis, the radius of said source being such that said dc term is located in said plane substantially entirely to one side of said axis, and means to rotate said source in said locus whereby to rotate said dc term about said axis.
Claim 11
Dependent Claim
108 words
In a coherent optical system for forming in a Fourier transform plane having a predetermined entrance pupil, from coherent illumination, a Fourier transform object located to modulate said illumination, said transform having a dc term and a series of spatial frequency components, the improvement comprising a source of coherent light appearing to be spaced transversely from said axis in a circular locus centered on said axis, the radius of said source being such that said dc term is located in said plane substantially entirely to one side of said axis, and means to rotate said source in said locus whereby to rotate said dc term about said axis.
Claim 12
Dependent Claim
27 words
A system according to claim 9 including an aperture member for stopping said tranform plane to an entrance pupil that at least partially blocks said dc term.
Claim 13
Dependent Claim
29 words
A system according to claim 9 in which said source is effectively spaced a distance from said axis such that said dc term falls essentially outside said entrance pupil.
Claim 14
Dependent Claim
72 words
A system according to claim 9 in which said entrance pupil has a size that would cut off spatial frequencies of said Fourier transform higher than the n-th component if said dc term were centered on said axis, said dc term being located substantially at the periphery of said entrance pupil, whereby rotation of said source in said locus will bring the 2n-th component of a diffracted image into said entrance pupil.
Claim 15
Dependent Claim
29 words
A system according to claim 9 having a real source of said coherent light in said locus, and means to rotate said source about said axis in said locus.
Claim 16
Dependent Claim
56 words
A system according to claim 9 having a real source of said light on said axis, optical means to deflect light from said source transversely to said axis for erecting a virtual source of said light in said locus, and means including said optical means to rotate said virtual source about said axis in said locus.
Claim 17
Dependent Claim
14 words
A system according to claim 9 including means substantially to block said dc term.
Claim 18
Dependent Claim
24 words
A system according to claim 9 including means to phase-shift said dc term substantially pi /2 relative to the remainder of said Fourier transform.
Claim 19
Dependent Claim
37 words
A system according to claim 9 including a spatial filter in said plane and means to rotate said filter about said axis synchronously with said source whereby to maintain said filter fixed relative to said Fourier transform.
References Cited (Backward Citations)
US3648039A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-05 | 1977-05-07 | 1977-11-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-05 | 1981-05-07 | 1981-11-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-05 | 1985-05-07 | 1985-11-06 | $7700.00 | Window Closed / Lapsed |