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US3876829A
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US
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Electro-optical communication of visual images
Assignee: Massachusetts Institute of Technology
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Filing: 1973-04-20
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Granted: 1975-04-08
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Expires: 1993-04-20
Abstract
Abstract Electro-optical system for communication of visual images, wherein a receiver reproduces transmitted images by effectively scanning a light beam over an imaging field, the receiver having an inherent spatial scanning frequency associated therewith, and the system includes optics for raising the effective spatial scanning frequency of the receiver to above the inherent frequency, the optics including means for dividing the light beam into multiple sub-beams spatially separated at the imaging field, to correspondingly raise the frequency of any Moire patterns upon ultimate reproduction of the images by a graphical process involving a spatially periodic line or dot structure.
Inventors
- 👤 William F Schreiber
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 21:59
CPC Classifications
H; H04; H04N; H04N1/00; H04N1/04; H04N1/12; H04N1/024; H04N1/032; H04N1/036; H04N1/113; H04N1/1135; H04N2201/00; H04N2201/04; H04N2201/0402; H04N2201/0458
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
124 words
In an electro-optical system for communication of images wherein a receiver receives signals and responsive thereto generates a modulated light beam, said receiver having beam deflection means which directs said beam in a periodic scan pattern against an image surface responsive to said beam to form an image thereon, the improvement wherein said receiver includes an aperture member positioned in said beam between its source and said beam deflection means, said aperture member having apertures therein forming said beam into a plurality of discrete sub-beams, adjacent sub-beams being at said surface displaced from one another in a direction non-parallel to the direction of beam scan, said receiver producing an image on said surface free of periodicity at the spatial frequency of said scan pattern.
Claim 2
Dependent Claim
124 words
In an electro-optical system for communication of images wherein a receiver receives signals and responsive thereto generates a modulated light beam, said receiver having beam deflection means which directs said beam in a periodic scan pattern against an image surface responsive to said beam to form an image thereon, the improvement wherein said receiver includes an aperture member positioned in said beam between its source and said beam deflection means, said aperture member having apertures therein forming said beam into a plurality of discrete sub-beams, adjacent sub-beams being at said surface displaced from one another in a direction non-parallel to the direction of beam scan, said receiver producing an image on said surface free of periodicity at the spatial frequency of said scan pattern.
Claim 3
Dependent Claim
52 words
The improvement as claimed in claim 1, said aperture member forming sub-beams of equal intensity and with displacements so proportional with respect to the scanning pattern that displacement between adjacent sub-beams respectively in different main beam scan positions is equal to displacement between adjacent sub-beams in a single main beam scan position.
Claim 4
Dependent Claim
56 words
The improvement in claim 1, wherein said system comprises a laser, a focusing lens, mirrors defining an optical path between said laser and said lens, a scanning mirror mounted behind said lens for receiving light passing therethrough, causing said light to scan said imaging field, and said aperture member mounted just in front of said lens.
Claim 5
Dependent Claim
28 words
The improvement of claim 1 wherein said aperture member includes apertures dividing said light beam into multiple sub-beams spatially separated along two orthogonal directions at said image surface.
Claim 6
Dependent Claim
50 words
The improvement as claimed in claim 1 said aperture member forming sub-beams with displacement between adjacent sub-beams to produce an overlapping on said surface of sub-beams from successive scan positions, said aperture member forming sub-beams of unequal intensity to provide equal exposure of said surface in overlapped and non-overlapped areas.
Claim 7
Dependent Claim
71 words
The improvement of claim 5 wherein said aperture member includes apertures dividing said light beam into a linear array of at least three sub-beams, including two outer sub-beams of half the intensity of an inner sub-beam, said apertures spaced to provide overlap at said imaging field of successive main beams to additively superimpose pairs of said outer sub-beams without superimposing said inner sub-beams thereby averaging light intensity at the beam edges.
Claim 8
Dependent Claim
24 words
The improvement of claim 6 wherein said aperture member includes at least three apertures, including outer apertures of lower transmissivity than an inner apertures.
Claim 9
Dependent Claim
12 words
The improvement in claim 7 wherein said apertures are equal in size.
Claim 10
Dependent Claim
82 words
The improvement of claim 5 herein said aperture member includes apertures dividing said beam into nine sub-beams arranged in a 3 .times. 3 matrix, including corner sub-beams of one quarter the intensity of the central sub-beam, and non-corner outside sub-beams of half the intensity of said central sub-beam, and means for causing overlap at said imaging field of successive main beams to additively superimpose sets of said outside sub-beams without superimposing said central sub-beams, thereby averaging light intensity at the beam edges.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |