Patent ID: 7370993

Claim:
An illumination system, comprising: at least one light emitting diode, wherein said at least one light emitting diode has a total emitting area, wherein said at least one light emitting diode emits internally generated light and wherein said at least one light emitting diode has a reflectivity to incident light; and a light recycling envelope that encloses said at least one light emitting diode, wherein said light recycling envelope has reflecting inside surfaces that recycle a part of said internally generated light emitted by said at least one light emitting diode back to said at least one light emitting diode; a light output aperture in said light recycling envelope, wherein a fraction of said internally generated light emitted by said at least one light emitting diode and reflected by said light recycling envelope exits said light recycling envelope through said light output aperture, wherein the area of said light output aperture is less than said total emitting area and wherein said fraction of said internally generated light exiting said light output aperture has a first angular range; and a partially reflecting optical element, wherein said partially reflecting optical element is located in the light optical path and proximal to said light output aperture, wherein said partially reflecting optical element transmits a first portion of said fraction of said internally generated light with a second angular range, smaller than said first angular range and wherein said partially reflecting optical element reflects a second portion of said fraction of said internally generated light back into said light recycling envelope.