US4642740A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant magnification light collection system
Assignee: Lockheed Martin Corp
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Filing: 1984-10-22
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Granted: 1987-02-10
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Expires: 2004-10-22
Abstract
Abstract A high efficiency light collection system for a projector such as a light valve projector provides constant tangential magnification for all zones so that the images of the source just fills the pupil of the projection system thereby giving the best source utilization in all zones. The light collection system comprises a reflector (60) behind the source and a correcting refractor (61) in front of the source. The preferred embodiment uses an aconic reflector having continuously changing zonal focus with a single asphere corrector lens that has exactly compensating zonal focus characteristics. It is also possible to use a conic reflector, but this requires two asphere corrector lenses in order to provide the constant tangential magnification characteristics.
Inventors
- 👤 Thomas T. True
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 15:52
CPC Classifications
F; F21; F21V; F21V5/00; F21V5/04; F21V5/048; G; G02; G02B; G02B19/00; G02B19/0004; G02B19/0028; G02B19/0033; G02B19/0047; F21W; F21W2131/00; F21W2131/40; F21W2131/406
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
107 words
In a light projection system for projecting light from a source, the improvement in a light collection system which satisfies the relationships for constant tangential magnification for all zones so that the image of the source just fills the pupil of the projection system thereby giving the best source utilization in all zones, said light collection system comprising: a reflector positioned behind the source; and a correcting refractor positioned in front of the source; the reflector having a reflection relationship to its surface contour and the refractor having a ray bending relationship to its surface contour such that together, they achieve the overall relationship Dφ.sub.1 /dφ.sub.2 =constant
Claim 2
Dependent Claim
107 words
In a light projection system for projecting light from a source, the improvement in a light collection system which satisfies the relationships for constant tangential magnification for all zones so that the image of the source just fills the pupil of the projection system thereby giving the best source utilization in all zones, said light collection system comprising: a reflector positioned behind the source; and a correcting refractor positioned in front of the source; the reflector having a reflection relationship to its surface contour and the refractor having a ray bending relationship to its surface contour such that together, they achieve the overall relationship Dφ.sub.1 /dφ.sub.2 =constant
Claim 3
Dependent Claim
17 words
where φ 1 is the collection angle and φ 2 is the final angle leaving the refractor.
Claim 4
Dependent Claim
17 words
where φ 1 is the collection angle and φ 2 is the final angle leaving the refractor.
Claim 5
Dependent Claim
79 words
The light collection system as recited in claim 1 wherein said reflector is an aconic mirror with a long focal distance at the rear and as the angle leaving the source is increased from the rear limit angle to the forward limit angle, the reflector focus distance shortens, and said refractor is a single asphere corrector lens having a positive lens power at the center and changes from positive through neutral to a negative lens power at the periphery.
Claim 6
Dependent Claim
17 words
The light collection system as recited in claim 2 wherein the corrector lens is an asphere lens.
Claim 7
Dependent Claim
81 words
The light collection system as recited in claim 3 wherein the geometry of ray intercepts are defined by the following relationships: ##EQU7## coordinates of mirror intercept with ray leaving the source at φ 1 angle, the lens intercept Y L and X L dimensions measured from the source are Y.sub.L =rsinφ.sub.1 -(X.sub.L +rcosφ.sub.1)tanφ.sub.1 ', where φ.sub.1 '=φ.sub.1 -2Δφ and dX.sub.L /dY.sub.L =tanAn.sub.L where An.sub.L is the lens normal to surface, sin(An.sub.L -φ.sub.1)=Ngsin(An.sub.L =φ.sub.2) dφ.sub.1 /dφ.sub.2 =tangential magnification=constant=M.sub.t φ.sub. = M.sub.t φ.sub.2.
Claim 8
Dependent Claim
17 words
The light collection system as recited in claim 2 wherein the corrector lens is an asphere/plano lens.
Claim 9
Dependent Claim
17 words
The light collection system as recited in claim 2 wherein the corrector lens is an asphere/concave lens.
Claim 10
Dependent Claim
24 words
The light collection system as recited in claim 1 wherein said reflector is a conic mirror and said refractor comprises two asphere corrector lenses.
Claim 11
Dependent Claim
26 words
The light collection system as recited in claim 1 wherein the light projection system is a light valve and said light source is an arc lamp.
Claim 12
Dependent Claim
33 words
The light collection system as recited in claim 8 wherein the projection system is of the type including an electron gun which emits an electron beam which impinges against a light modulating medium.
Claim 13
Dependent Claim
62 words
The light collection system as recited in claim 9 wherein said electron gun and said arc lamp are coaxial with the axis of revolution of said reflector, said system further comprising a lenticular lens assembly coaxial with said axis of revolution and located forward of said reflector, said lenticular lens assembly including slots for controlling light projected by said light collection system.
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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) | 1990-02-09 | 1990-08-11 | 1991-02-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-09 | 1994-08-11 | 1995-02-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-09 | 1998-08-11 | 1999-02-10 | $7700.00 | Window Closed / Lapsed |