Patent ID: 8278841

Claim:
A lighting apparatus for producing high brightness, said lighting apparatus comprising: a high thermal conductivity printed circuit board; at least one bare LED die comprising one or more LED emitting areas for generating radiation of one or more spectral bands over a predetermined solid angle, said at least one bare LED die being attached to said high thermal conductivity printed circuit board with a thermally conductive bonding layer; an electronic control module attached to said high thermal conductivity printed circuit board for controlling the output of said LED emitting areas; a photosensor attached to said high thermal conductivity printed circuit board at a predetermined spaced apart location with respect to said LED die for providing a feedback signal to said electronic control module to regulate the output of said LED emitting areas; and at least one non-imaging concentrator fixedly attached to and in registration with said high thermal conductivity printed circuit board, said non-imaging concentrator having entrance and exit apertures, said non-imaging concentrator entrance aperture being optically aligned with said LED emitting areas for collecting radiation from said LED emitting areas and re-emitting it through said non-imaging concentrator exit aperture with an étendue substantially the same as that of said LED emitting areas, said non-imaging concentrator having prismatic optical elements positioned near said exit aperture for sampling the light emitted near said exit aperture and directing it along a folded optical path to said photosensor as an optical signal indicative of the intensity of radiation exiting said non-imaging concentrator.