US3650595A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Redundant, speckle-free hologram recording apparatus
Assignee: RCA Corp
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Filing: 1970-04-24
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Granted: 1972-03-21
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Expires: 1990-04-24
Abstract
Abstract There is disclosed the use of a phase diffraction, rather than a plate of diffusing glass, for introducing redundancy into the information beam which is employed together with a reference beam in recording a hologram. The use of a phase diffraction grating eliminates the presence of unwanted speckle noise in the reproduced image of the hologram, which speckle noise is present to a large degree when a small sized hologram is recorded with a diffused light information beam.
Inventors
- 👤 Hendrik J Gerritsen
- 👤 William J Hannan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:56
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
15 words
The apparatus defined in claim 1 wherein said redundancy means comprises a phase diffraction grating.
Claim 2
Dependent Claim
14 words
The apparatus defined in claim 2, wherein said phase diffraction grating is two dimensional.
Claim 3
Dependent Claim
72 words
The apparatus defined in claim 1, wherein said redundancy means includes means for diffracting the information beam impinging on said recording medium by an angular amount with respect to said given dimensions to provide a zero-order beam symmetrically disposed about the bisector of a given dimension of said hologram and each of two first-order beams symmetrically disposed about each respective opposite one of the ends of that given dimension of said hologram.
Claim 4
Dependent Claim
24 words
The apparatus defined in claim 4, wherein the relative intensities of said zero-order beam and each of said first-order beams are all substantially equal.
Claim 5
Dependent Claim
17 words
The apparatus defined in claim 4, wherein said given area is no greater than ten square millimeters.
Claim 6
Dependent Claim
18 words
The apparatus defined in claim 6, wherein said given area is in the order of one square millimeter.
Claim 7
Dependent Claim
76 words
The apparatus defined in claim 4, wherein said hologram is a micro-hologram, and wherein said first means includes a transparency having information thereon which transparency is of a size larger than said microhologram, a phase diffraction grating, a convex lens, and means for transmitting said spatially coherent electromagnetic waves through said grating, said lens and said transparency in that order to obtain a convergent information beam which impinges on said given area of said recording medium.
Claim 8
Dependent Claim
57 words
The apparatus defined in claim 8, wherein phase diffraction grating has a given line spacing which causes a noise interference pattern to be generated over said given area of said recording medium, said given line spacing being sufficiently small to cause the maximum spacing in said noise interference pattern to be no greater than said resolution limit.
Claim 9
Dependent Claim
17 words
The apparatus defined in claim 9, wherein said phase diffraction grating is a sinusoidal phase diffraction grating.
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) | 1975-03-21 | 1975-09-20 | 1976-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-21 | 1979-09-20 | 1980-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-21 | 1983-09-20 | 1984-03-21 | $7700.00 | Window Closed / Lapsed |