Patent US4121882A successfully refreshed from Google Patents.
US4121882A
Expired / Lapsed
US
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Flat scan holographic laser beam deflector
Assignee: International Business Machines Corp
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Filing: 1976-12-29
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Granted: 1978-10-24
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Expires: 1996-12-29
Abstract
Abstract A holographic laser beam deflector has an approximately flat field scan. The scan is produced by illuminating a rotating hologram on a circular surface by a laser beam. The virtual source of the illuminating beam is offset from the center of rotation of the hologram. The hologram is produced by interference of a pair of coherent laser beams, each beam having a source or virtual source on a line containing the rotational center of the surface of the hologram, one source or virtual source outside the surface, the other inside. The virtual source for the inside beam is also displaced from the center of rotation.
Inventors
- 👤 James M. White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 19:31
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
95 words
A flat field scanning device to provide an essentially flat field scan comprising: a circular cylindrical drum having at least a transparent segment and means for rotating said drum about its central axis, a hologram mounted on each said transparent segment of said drum, and light source means of wavelength equal to wavelength of beams employed to produce said hologram for illuminating said hologram, said light source means having a virtual source within said drum located on a line perpendicular to, and intersecting said axis, said virtual source spaced on said line from said axis.
Claim 2
Dependent Claim
95 words
A flat field scanning device to provide an essentially flat field scan comprising: a circular cylindrical drum having at least a transparent segment and means for rotating said drum about its central axis, a hologram mounted on each said transparent segment of said drum, and light source means of wavelength equal to wavelength of beams employed to produce said hologram for illuminating said hologram, said light source means having a virtual source within said drum located on a line perpendicular to, and intersecting said axis, said virtual source spaced on said line from said axis.
Claim 3
Dependent Claim
37 words
The apparatus of claim 1 wherein, said hologram is produced by interfering coherent light beams each with a virtual source, at least one of said virtual sources lying inside said drum and offset from said drum axis.
Claim 4
Dependent Claim
36 words
The apparatus of claim 1 wherein said light source means comprises a laser means and lens, said laser means directing a light beam to said lens, said lens selected and located to provide said virtual source.
Claim 5
Dependent Claim
20 words
The apparatus of claim 3 which further includes aperture stop means to limit said light beam impinging on said hologram.
Claim 6
Dependent Claim
32 words
The apparatus of claim 4 in which said aperture stop means is located to provide a diffraction limit to beam resolution in said scan field equal to aberration limit to beam resolution.
Claim 7
Dependent Claim
34 words
The apparatus of claim 3 wherein said laser means comprises a laser, and a mirror, said mirror located on a line intersecting said lens and said hologram, said laser directed to illuminate said mirror.
Claim 8
Dependent Claim
83 words
Apparatus for producing a hologram useful in a flat field scanning device comprising: a circular cylindrical drum having at least a transparent segment and means for rotating said drum about its central axis, optically responsive means for recording a hologram located on said transparent segment of said drum, a pair of coherent light sources each having a virtual source on a line intersecting said axis, one of said virtual sources lying inside said drum, said one virtual source offset from said central axis.
Claim 9
Dependent Claim
83 words
Apparatus for producing a hologram useful in a flat field scanning device comprising: a circular cylindrical drum having at least a transparent segment and means for rotating said drum about its central axis, optically responsive means for recording a hologram located on said transparent segment of said drum, a pair of coherent light sources each having a virtual source on a line intersecting said axis, one of said virtual sources lying inside said drum, said one virtual source offset from said central axis.
Claim 10
Independent Claim
88 words
A method of scanning a flat field comprising the steps of (a) recording a hologram on a segment of a circular cylinder by interfering a pair of coherent light sources each providing light beams of aperture A at said segment; (b) illuminating at least a portion of said hologram with a third source of wavelength equal to said coherent light sources, said third source having, at said segment, an aperture B<A and a virtual source offset from the axis of said cylinder segment, and (c) rotating said cylinder.
Claim 11
Independent Claim
88 words
A method of scanning a flat field comprising the steps of (a) recording a hologram on a segment of a circular cylinder by interfering a pair of coherent light sources each providing light beams of aperture A at said segment; (b) illuminating at least a portion of said hologram with a third source of wavelength equal to said coherent light sources, said third source having, at said segment, an aperture B<A and a virtual source offset from the axis of said cylinder segment, and (c) rotating said cylinder.
Claim 12
Dependent Claim
30 words
The method of claim 8 wherein said step (a) further comprises locating one of said sources inside said cylinder with a virtual source offset from the axis of said cylinder.
Claim 13
Dependent Claim
43 words
The method of claim 8 which provides for repetitive scanning of said field and in which plural holograms are recorded in different segments of said cylinder in a band and said third source illuminates different holograms, in turn, as said cylinder is rotated.
Claim 14
Dependent Claim
30 words
The method of claim 8 which comprises the further step of (d) providing at least one aperture stop to limit the portion of said hologram illuminated by said third source.
Claim 15
Dependent Claim
29 words
The method of claim 11 in which said at least one aperture stop is located to provide a diffraction limit to resolution equal to the aberration limit to resolution.
Claim 16
Dependent Claim
26 words
The method of claim 9 in which said offsets are selected to provide a scanned line straight to within ±5% of a radius of said cylinder.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-10-23 | 1982-04-24 | 1982-10-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-10-23 | 1986-04-24 | 1986-10-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-10-23 | 1990-04-24 | 1990-10-24 | $7700.00 | Window Closed / Lapsed |