Patent ID: 7025464

Claim:
A projection display system, comprising: a light-recycling illumination system, wherein said light-recycling illumination system further comprises: a light source for generating light, wherein said light source is at least one light-emitting diode having a reflecting layer, wherein the total light-emitting area of said light source is area A S and wherein said light source has a maximum intrinsic source luminance and; a light-recycling envelope, wherein said light-recycling envelope encloses said light source and wherein said light-recycling envelope reflects and recycles a portion of said light generated by said light source back to said reflecting layer; and a light output aperture, wherein said light output aperture is located in a surface of said light-recycling envelope, wherein the area of said light output aperture is area A O , wherein said area A O is less than said area A S , wherein said light source and said light-recycling envelope direct at least a fraction of said light out of said light-recycling envelope through said light output aperture and wherein said fraction of said light exits said light output aperture as uncollimated light having a maximum exiting luminance; a light-collimating means, wherein said light-collimating means has an input surface that is adjacent to said light output aperture that accepts said uncollimated light, wherein said light-collimating means partially collimates said uncollimated light and wherein said light-collimating means has an output surface through which the partially collimated light is transmitted; and an imaging light modulator, wherein said imaging light modulator is located in the optical path of said partially collimated light, and wherein said imaging light modulator spatially modulates said partially collimated light to form an image.