A projection display system has at least one light-recycling illumination
system and at least one imaging light modulator. The light-recycling
illumination system includes a light source that is enclosed within a
light-recycling cavity. The light source is a plurality of light-emitting
diode that emits light, and a fraction of that light will exit the
light-recycling cavity through an aperture. The light-recycling cavity
recycles a portion of the light emitted by the light source back to the
light source in order to enhance the luminance of the light exiting the
aperture. The fraction of the light that exits the aperture is partially
collimated and is directed to the imaging light modulator. The imaging
light modulator spatially modulates the partially collimated light to
form an image.