LED luminance-augmentation via specular retroreflection, including collimators that escape the étendue limit
First Claim
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1. A collimating luminaire comprising:
- a light-source with a diffuse reflectivity exceeding one half,said collimating luminaire intercepting the emitted light of said source, said luminaire producing a substantially uniform beamwidth across its exit aperture, anda system of specular retroreflectors comprising at least one concave retroreflector that returns part of said emitted light to said source, said retroreflectors allowing the removal of the outer part of said exit aperture, so that said exit aperture is smaller than the é
tendue-limited aperture for said beamwidth,wherein part of said emitted light that is returned to said source by said system of retroreflectors is then returned towards said exit aperture by said diffuse reflectivity of said source.
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Abstract
The diffuse reflectivity of an LED source is utilized to recycle some of its emission, thereby enabling a luminaire to escape the étendue limit. Retroreflectors intercept the rays destined for the outer part of the luminaire aperture, which can then be truncated. The resulting smaller aperture has the same beam-width as the full original, albeit with lesser flux due to recycling losses. A reduction to half the original area is possible.
21 Citations
20 Claims
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1. A collimating luminaire comprising:
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a light-source with a diffuse reflectivity exceeding one half, said collimating luminaire intercepting the emitted light of said source, said luminaire producing a substantially uniform beamwidth across its exit aperture, and a system of specular retroreflectors comprising at least one concave retroreflector that returns part of said emitted light to said source, said retroreflectors allowing the removal of the outer part of said exit aperture, so that said exit aperture is smaller than the é
tendue-limited aperture for said beamwidth,wherein part of said emitted light that is returned to said source by said system of retroreflectors is then returned towards said exit aperture by said diffuse reflectivity of said source. - View Dependent Claims (14, 15, 16, 17, 18, 20)
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- 2. A collimating luminaire comprising a light-source with a diffuse reflectivity exceeding one half, said luminaire defining an exit aperture and intercepting the emitted light of said source in directions outside the exit aperture, said luminaire comprising at least one at least approximately elliptically concave specular retroreflector that returns part of said emitted light to said source, wherein part of said emitted light that is returned to said source by said system of retroreflectors is then returned towards said exit aperture by said diffuse reflectivity of said source.
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7. A collimating luminaire comprising a light-source with a diffuse reflectivity exceeding one half, said luminaire defining an exit aperture and intercepting the emitted light of said source in directions outside the exit aperture, said luminaire comprising at least one at least approximately elliptically concave retroreflector that returns part of said emitted light to said source, and further comprising at least one forward reflector positioned to direct intercepted light through the exit aperture in such a manner as to produce a substantially uniform beamwidth across the exit aperture wherein the exit aperture is smaller than the é
- tendue-limited aperture for said beamwidth.
- View Dependent Claims (8, 9, 10, 11, 12)
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13. A collimating luminaire comprising:
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a light-source with a diffuse reflectivity exceeding one half, said collimating luminaire intercepting the emitted light of said source, said luminaire producing a substantially uniform beamwidth across its exit aperture, and a system of forward reflectors comprising at least one said forward reflector lying along a flowline of the light from the source that directs part of said emitted light to said exit aperture, said system of reflectors allowing the removal of the outer part of said exit aperture, so that said exit aperture is smaller than the é
tendue-limited aperture for said beamwidth.
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Specification