Abstract: A polarized light converting system is disclosed in the present invention. The converting system includes a polarizing splitting unit, for splitting an unpolarized incident light beam into a first polarized light beam and a second polarized light beam, passing the second polarized light beam, and reflecting the first polarized light beam; a reflector for reflecting the second polarized light beam back through the polarizing splitting unit; a condensing unit, for guiding the condensed first polarized light beam through a first area and the condensed second polarized light beam through a second area which does not overlap the first area; and a retarder unit placed at either the first area or the second area for converting the unpolarized incident light beam into polarized light beams having the same polarization state such that illumination efficiency can be increased.

Abstract: An illumination system for a projection display is disclosed in the present invention. The illumination system has three light sources for providing three primary color rays, two collimators for collimating the rays into light beams, and two beam splitters for reflecting and passing the light beams to make white light available. It can also include three light sources, one collimator and three individual beam splitters. The illumination system has a compact size and low manufacturing cost. Its lighting efficiency is better than that of a conventional illumination system. Hence, it is suitable for small size projectors.

Abstract: A projection system includes a multi-laser beam generator, a beam switching device, a split beam projecting device and a transmissive light valve. The multi-laser beam generator selectively generates a red beam, a green beam and a blue beam. The beam switching device receives the red, green and blue beams, splits the red, green and blue beams into a plurality of light beams of different angles, and directs the red, green and blue beams of the different angles into a common optical path. The split beam projecting device includes a plurality of micro-lenses. The transmissive light valve has a plurality of pixels for receiving the red, green and blue beams that are guided by the split beam projecting device. The red, green and blue beams of the different angles are received by the micro-lenses and guided onto the pixels of the transmissive light valve for imagining on the pixels.