US5262893A
Expired / Lapsed
US
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Method and apparatus for creating multiple phase level optical elements
Assignee: Massachusetts Institute of Technology
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Filing: 1991-11-04
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Granted: 1993-11-16
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Expires: 2011-11-04
Abstract
Abstract Method and apparatus for creating discrete phase optical elements. An arbitrary phase structure is represented by color encoding to produce a color encoded mask. Thereafter, a photo-sensitive substrate is exposed to broad spectrum light transmitted through or reflected from the mask to create the discrete phase structure in the substrate. In preferred embodiments, the exposed substrate is developed and bleached (if necessary) to remove pigmentation to produce highly efficient multiple level phase structures for optical applications. The color encoded mask is produced by a computer-driven color printer resulting in very fast turnaround times.
Inventors
- 👤 Vernon E. Shrauger
- 👤 Cardinal Warde
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 04:08
CPC Classifications
G; G03; G03H; G03H1/00; G03H1/04; G03H1/08; G02; G02B; G02B5/00; G02B5/18; G02B5/1866; G02B5/1871; G02B5/1876; G02B5/188; G02B5/1885; G02B5/32; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/2804; G02B6/2848; G02B6/42; G03H1/0841; G03H1/0476; G03H2001/048; G03H2240/00; G03H2240/20; G03H2240/40; G03H2240/42
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
65 words
Method for creating discrete phase optical elements having K phase levels, where K is greater than 2, comprising: representing a preselected phase structure by color encoding to produce a color encoded mask; and exposing a photosensitive substrate to light transmitted through or reflected from the mask to create the discrete phase structure having K phase levels, where K is greater than 2, in the substrate.
Claim 2
Dependent Claim
65 words
Method for creating discrete phase optical elements having K phase levels, where K is greater than 2, comprising: representing a preselected phase structure by color encoding to produce a color encoded mask; and exposing a photosensitive substrate to light transmitted through or reflected from the mask to create the discrete phase structure having K phase levels, where K is greater than 2, in the substrate.
Claim 3
Dependent Claim
26 words
The method of claim 1 wherein particular phase levels of the arbitrary phase structure are encoded by colors selected according to the colors' corresponding optical densities.
Claim 4
Dependent Claim
16 words
The method of claim 1 wherein the mask is created by a computer driven color printer.
Claim 5
Dependent Claim
15 words
The method of claim 3 wherein the color printer can create at least three colors.
Claim 6
Dependent Claim
18 words
The method of claim 3 wherein the color printer has a resolution greater than 10 dots per inch.
Claim 7
Dependent Claim
16 words
The method of claim 1 wherein the mask is created by a computer driven display device.
Claim 8
Dependent Claim
12 words
The method of claim 1 wherein the mask includes a transparent substrate.
Claim 9
Dependent Claim
13 words
The method of claim 1 wherein the mask includes an opaque, reflective substrate.
Claim 10
Dependent Claim
18 words
The method of claim 1 wherein the photosensitive substrate has an approximately flat spectral response to visible light.
Claim 11
Dependent Claim
23 words
The method of claim 1 wherein the photosensitive substrate spectral response is filter corrected for an approximate flat spectral response to visible light.
Claim 12
Dependent Claim
21 words
The method of claim 1 wherein cascaded color masks are used to create compensating colors for non-flat spectral response photosensitive substrates.
Claim 13
Independent Claim
17 words
The method of claims 9 or 10 or 11 wherein the photosensitive substrate is a photographic emulsion.
Claim 14
Dependent Claim
11 words
The method of claim 12 further including developing the photographic emulsion.
Claim 15
Dependent Claim
14 words
The method of claim 13 further including bleaching the photographic emulsion to remove pigmentation.
Claim 16
Independent Claim
32 words
The method of claims 9 or 10 or 11 wherein the photosensitive substrate is a photopolymer material, dichromated gelatin, photoresist, photorefractive material, or other photosensitive material that is capable of phase-only recording.
Claim 17
Dependent Claim
18 words
The method of claim 15 further including appropriate processing to establish the phase structure within the photosensitive substrate.
Claim 18
Dependent Claim
57 words
Apparatus for creating discrete phase optical elements having K phase levels, where K is greater than 2, comprising: apparatus for generating spatially varying color encoded light; and a photosensitive substrate exposed to the color encoded light, and a preselected discrete phase structure having K phase levels, where K is greater than 2, is created in the substrate.
Claim 19
Dependent Claim
57 words
Apparatus for creating discrete phase optical elements having K phase levels, where K is greater than 2, comprising: apparatus for generating spatially varying color encoded light; and a photosensitive substrate exposed to the color encoded light, and a preselected discrete phase structure having K phase levels, where K is greater than 2, is created in the substrate.
Claim 20
Dependent Claim
56 words
Apparatus for creating phase optical elements having K phase levels, where K is greater than 2, comprising: a color encoded mask; and a photosensitive substrate exposed to light transmitted through or reflected from the mask, and a preselected discrete phase structure having K phase levels, where K is greater than 2, is created in the substrate.
Claim 21
Dependent Claim
56 words
Apparatus for creating phase optical elements having K phase levels, where K is greater than 2, comprising: a color encoded mask; and a photosensitive substrate exposed to light transmitted through or reflected from the mask, and a preselected discrete phase structure having K phase levels, where K is greater than 2, is created in the substrate.
Claim 22
Dependent Claim
27 words
The apparatus of claim 18 further including a computer running software; and a color printer driven by the computer and adapted to print the color encoded mask.
Claim 23
Dependent Claim
16 words
The apparatus of claim 18 wherein the apparatus for exposing the photosensitive substrate includes photoreduction optics.
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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) | 1996-11-15 | 1997-05-17 | 1997-11-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-11-15 | 2001-05-17 | 2001-11-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-11-15 | 2005-05-17 | 2005-11-16 | $7700.00 | Window Closed / Lapsed |