A projection display system has at least one light-recycling illumination system,
a color scroller and an imaging light modulator. The light-recycling illumination
system includes a light source that is enclosed within a light-recycling envelope.
The light source is a light-emitting diode that emits light, and a fraction of
that light will exit the light-recycling envelope through an aperture. The light-recycling
envelope 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 a color scrolling means. The color scroller scans the partially collimated
light across the face of the imaging light modulator. The imaging light modulator
spatially modulates the scrolled beam of light to form an image.