US5016953A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Reduction of noise in computer generated holograms
Assignee: Dai Nippon Printing Co Ltd
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Filing: 1989-08-31
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Granted: 1991-05-21
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Expires: 2009-08-31
Abstract
Abstract Noise is reduced in computer generated holograms (CGH's) by a method of overexposure. The CGH is used to make a master hologram. The master hologram is then used to make a copy from which a succession of other copy holograms is made. Each successive copy hologram is exposed less than the prior ones while increasing brightness uniformity. Consequently, a decreasing amount of change in exposure is required to reach 100% efficiency. The number and orientation of the copy holograms is incorporated into the design of the final optical element. The final hologram is not overexposed, since the amount of exposure has been reduced from the earlier holograms, and can be used in complex optical power systems.
Inventors
- 👤 Gaylord E. Moss
- 👤 John E. Wreede
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 20:15
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/20; G03H1/08
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
54 words
A method of reducing noise in computer generated holograms, comprising the steps of: making a succession of intermediate copy holograms from a computer generated hologram; and varying an exposure of each intermediate copy hologram made wherein each intermediate copy hologram is subject to an exposure that is less than an earlier made copy hologram.
Claim 2
Independent Claim
54 words
A method of reducing noise in computer generated holograms, comprising the steps of: making a succession of intermediate copy holograms from a computer generated hologram; and varying an exposure of each intermediate copy hologram made wherein each intermediate copy hologram is subject to an exposure that is less than an earlier made copy hologram.
Claim 3
Dependent Claim
28 words
The method according to claim 1 further including the step of utilizing each intermediate copy hologram to make one of another intermediate copy hologram and a final hologram.
Claim 4
Dependent Claim
22 words
The method according to claim 1 further including the step of bringing said copy holograms successively towards an ideal overall brightness uniformity.
Claim 5
Dependent Claim
35 words
The method according to claim 1 further including the step of successively approaching an optimum brightness uniformity and thus overall efficiency in a final hologram by successively decreasing an exposure of said intermediate copy holograms.
Claim 6
Dependent Claim
55 words
In an improved method for producing intermediate copy holograms from a master hologram, wherein the improvement comprises the steps of: making a succession of intermediate copy holograms from one another while decreasing an exposure of each intermediate copy hologram over a previously made intermediate copy hologram from which said former intermediate copy hologram was made.
Claim 7
Dependent Claim
55 words
In an improved method for producing intermediate copy holograms from a master hologram, wherein the improvement comprises the steps of: making a succession of intermediate copy holograms from one another while decreasing an exposure of each intermediate copy hologram over a previously made intermediate copy hologram from which said former intermediate copy hologram was made.
Claim 8
Dependent Claim
31 words
The improvement according to claim 5 further including the steps of producing a master hologram from a computer generated hologram, said master hologram being used to produce an intermediate copy hologram.
Claim 9
Dependent Claim
21 words
The improvement according to claim 6 wherein the step of producing said master hologram occurs in a double beam exposure system.
Claim 10
Dependent Claim
22 words
The improvement according to claim 7 wherein the step of making said intermediate copy holograms occurs in a single beam exposure system.
Claim 11
Dependent Claim
38 words
The improvement according to claim 8 further including the step of adjusting an exposure position of each intermediate copy hologram in said single beam exposure system relative to another exposure position of an earlier made intermediate copy hologram.
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) | 1994-05-20 | 1994-11-19 | 1995-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-05-20 | 1998-11-19 | 1999-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-05-20 | 2002-11-19 | 2003-05-21 | $7700.00 | Window Closed / Lapsed |