Patent US5146248A successfully refreshed from Google Patents.
US5146248A
Expired / Lapsed
US
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Light valve projection system with improved illumination
Assignee: Philips North America LLC
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Filing: 1988-12-09
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Granted: 1992-09-08
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Expires: 2008-12-09
Abstract
Abstract A light valve projection system includes an illumination system having a light collector in the form of a non-imaging reflector with a rectangular input aperture and a rectangular output aperture. A two dimensional light source at the input aperture illuminates the output aperture substantially uniformly.
Inventors
- 👤 Arne L. Duwaer
- 👤 Jill F. Goldenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 09:56
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/12; H04N9/31; H04N9/3141; H04N9/315; H04N9/3152; G; G02; G02B; G02B19/00; G02B19/0004; G02B19/0028; G02B19/0033; G02B19/0038; G02B19/0042; G02B19/0047
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
203 words
A projection system of the type comprising a first illumination subsystem, a first rectangular modulating device in the path of light emitted by said illumination subsystem, and a projection means for projecting the image of said modulating device, characterized in that said illumination subsystem comprises a first non-imaging reflector having a rectangular input aperture defining an XY plane, a rectangular output aperture, and a central Z axis of an XYZ coordinate system, said subsystem further comprising a first light source situation outside said non-imaging reflector and illuminating the input aperture thereof for illuminating the modulating device at least substantially homogeneously said non-imaging reflector satisfying the relationship D ix n i sin θ ix =D ox n o sin θ ox and D iy n i sinθ iy =D oy n o sinθ oy , where D ix and D iy are the dimensions of the input apertures, θ ix and θ iy are the maximum angles of incidence, D ox and D oy are the dimensions of the output aperture, θ ox and θ oy are the maximum emission angles, n i is the index of refraction at the input aperture, and n o is the index of refraction at the output aperture.
Claim 2
Dependent Claim
203 words
A projection system of the type comprising a first illumination subsystem, a first rectangular modulating device in the path of light emitted by said illumination subsystem, and a projection means for projecting the image of said modulating device, characterized in that said illumination subsystem comprises a first non-imaging reflector having a rectangular input aperture defining an XY plane, a rectangular output aperture, and a central Z axis of an XYZ coordinate system, said subsystem further comprising a first light source situation outside said non-imaging reflector and illuminating the input aperture thereof for illuminating the modulating device at least substantially homogeneously said non-imaging reflector satisfying the relationship D ix n i sin θ ix =D ox n o sin θ ox and D iy n i sinθ iy =D oy n o sinθ oy , where D ix and D iy are the dimensions of the input apertures, θ ix and θ iy are the maximum angles of incidence, D ox and D oy are the dimensions of the output aperture, θ ox and θ oy are the maximum emission angles, n i is the index of refraction at the input aperture, and n o is the index of refraction at the output aperture.
Claim 3
Dependent Claim
32 words
A projection system as in claim 1 wherein a cross-section of the reflector take in the XZ plane traverses the widest orthogonal dimension of the rectangular apertures and comprises a compound parabola.
Claim 4
Dependent Claim
54 words
A projection system as in claim 2 wherein the cross section of the reflector taken in the YZ plane, also comprises a compound parabola and further comprises parallel bounding surfaces adjacent said output aperture, the compound parabola of said cross section in the YZ plane extending between said input aperture and said parallel surfaces.
Claim 5
Dependent Claim
34 words
A projection system as in claim 1 wherein said light source comprises a reflective collector having a lamp therein and having an output aperture which coincides with the input aperture of said non-imaging reflector.
Claim 6
Dependent Claim
25 words
A projection system as in claim 1 wherein the deviation angle of light exiting from said output aperture is less than or equal to 15°.
Claim 7
Dependent Claim
27 words
A projection system as in claim 1 wherein said first modulating device is immediately adjacent said output aperture, said output aperture being illuminated at least substantially uniformly.
Claim 8
Dependent Claim
77 words
A projection system as in claim 1 further comprising respective second and third non-imaging reflectors defined as said first non-imaging reflector, second and third rectangular modulating devices outside of respective second and third reflectors and illuminating the input apertures thereof, second and third modulating devices in the path of light emitted by the output apertures of respective second and third reflectors, and means for combining the images of said modulating devices for projecting by said projection means.
Claim 9
Dependent Claim
31 words
A projection system as in claim 7 wherein for each reflector a cross-section taken through the central axis across the widest orthogonal dimension of the rectangular apertures comprises a compound parabola.
Claim 10
Dependent Claim
54 words
A projection system as in claim 8 wherein for each reflector the cross-section taken across the shortest dimension of the rectangular apertures also comprises a compound parabola and further comprises parallel bounding surfaces adjacent the respective output aperture, the compound parabola of said cross-section extending between the respective input aperture and said parallel surfaces.
Claim 11
Dependent Claim
36 words
A projection system as in claim 7 wherein each said light source comprises a reflective collector having a lamp therein and having an output aperture which coincides with the input aperture of said non imaging reflector.
Claim 12
Dependent Claim
25 words
A projection system as in claim 8 wherein said lamps are respectively spectrally tuned to the red, blue, and green portions of the visible spectrum.
Claim 13
Dependent Claim
23 words
A projection system as in claim 10 wherein said means for combining the images of said modulating devices comprises a dichroic prism system.
Claim 14
Dependent Claim
28 words
A projection system as in claim 7 wherein the deviation angle of light exiting from said output aperture of said reflector is less than or equal to 15°.
Claim 15
Dependent Claim
16 words
A projection system as in claim 13 wherein said projection means comprises an F/2 projection lens.
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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) | 1995-09-08 | 1996-03-09 | 1996-09-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-09-08 | 2000-03-09 | 2000-09-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-09-08 | 2004-03-09 | 2004-09-08 | $7700.00 | Window Closed / Lapsed |