US5621486A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Efficient optical system for a high resolution projection display employing reflection light valves
Assignee: GlobalFoundries Inc
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Filing: 1995-06-22
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Granted: 1997-04-15
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Expires: 2015-06-22
Abstract
Abstract An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system having a light tunnel, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display.
Inventors
- 👤 Fuad Doany
- 👤 Derek B. Dove
- 👤 Rama Singh
- 👤 Alan Rosenbluth
- 👤 George Chiu
- 👤 Thomas Cipolla
- 👤 Janusz Wilczynski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 01:45
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3102; H04N9/3105
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
139 words
An apparatus for projecting an image comprising: a color splitting prism assembly having a plurality of output-input faces; a reflective spatial light modulator at each of said output-input faces, each of said spatial light modulators having a reflective surface defining a geometrical shape; a light tunnel positioned within a first light path between a light source and said color splitting prism assembly, said light tunnel having a cross-sectional shape corresponding to said geometrical shape; a color filter positioned between each of said reflective surfaces and said output-input faces; a polarizing beam splitter positioned within said first light path; a projection lens positioned in a second light path between said polarizing beam splitter and a screen; means for suppressing stray light reflected from said screen back into said projection lens; and means for suppressing ambient light from illuminating said screen.
Claim 2
Independent Claim
139 words
An apparatus for projecting an image comprising: a color splitting prism assembly having a plurality of output-input faces; a reflective spatial light modulator at each of said output-input faces, each of said spatial light modulators having a reflective surface defining a geometrical shape; a light tunnel positioned within a first light path between a light source and said color splitting prism assembly, said light tunnel having a cross-sectional shape corresponding to said geometrical shape; a color filter positioned between each of said reflective surfaces and said output-input faces; a polarizing beam splitter positioned within said first light path; a projection lens positioned in a second light path between said polarizing beam splitter and a screen; means for suppressing stray light reflected from said screen back into said projection lens; and means for suppressing ambient light from illuminating said screen.
Claim 3
Dependent Claim
18 words
The apparatus of claim 1 wherein said reflective spatial light modulator includes a liquid crystal light valve assembly.
Claim 4
Dependent Claim
28 words
The apparatus of claim 1 wherein said color splitting prism assembly is comprised of three solid glass prisms forming two color separating surfaces located internally of said assembly.
Claim 5
Dependent Claim
28 words
The apparatus of claim 1 wherein said polarizing beam splitter is comprised of two solid glass prisms forming a polarization separating surface internally of said beam splitting means.
Claim 6
Dependent Claim
21 words
The apparatus of claim 1 further including means for filtering out ultraviolet and infrared light positioned within said first light path.
Claim 7
Dependent Claim
27 words
The apparatus according to claim 1 further including a pre-polarizing filter positioned within said first light path between the light source and said polarizing beam splitting means.
Claim 8
Dependent Claim
27 words
The apparatus according to claim 1 further including a post-polarizing filter positioned within said second light path between said polarizing beam splitting means and said projection lens.
Claim 9
Dependent Claim
27 words
The apparatus according to claim 6 further including a post-polarizing filter positioned within said second light path between said polarizing beam splitting means and said projection lens.
Claim 10
Dependent Claim
27 words
The apparatus according to claim 1 further including a color absorbing film disposed within said first light path between said light source and said polarizing beam splitter.
Claim 11
Dependent Claim
16 words
The apparatus of claim 1 wherein said light tunnel is comprised of a plurality of mirrors.
Claim 12
Dependent Claim
21 words
The apparatus of claim 10 wherein said light tunnel is comprised of four mirrors assembled to form a hollow rectangular tunnel.
Claim 13
Dependent Claim
14 words
The apparatus of claim 1 wherein said light tunnel is comprised of solid glass.
Claim 14
Dependent Claim
17 words
The apparatus of claim 1 further including a plurality of lenses positioned within said first light path.
Claim 15
Dependent Claim
28 words
The apparatus according to claim 1 wherein said means for suppressing stray light reflected from said screen includes a quarter wave plate positioned within said second light path.
Claim 16
Dependent Claim
51 words
The apparatus of claim 1 wherein said means for suppressing ambient light includes a quarter wave plate and a polarizing film placed on said screen, said polarizing film being positioned on the viewing side of said screen and said quarter wave plate being positioned between said polarizing film and said screen.
Claim 17
Dependent Claim
56 words
The apparatus of claim 1 wherein said means for suppressing ambient light includes at least one quarter wave film and a polarizing film placed on said screen, said polarizing film being positioned on the viewing side of said screen and said at least one quarter wave film being positioned between said polarizing film and said screen.
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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) | 2000-04-14 | 2000-10-14 | 2001-04-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-04-14 | 2004-10-14 | 2005-04-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-04-14 | 2008-10-14 | 2009-04-15 | $7700.00 | Window Closed / Lapsed |