Patent ID: 6018214
Filing Date: 2000-01-25
Classification: H04N

Abstract:
An illumination system for supplying a polarized radiation beam, which system comprises two radiation sources and an optical system for concentrating the radiation from each said source to a beam, a common polarizing system for splitting the beams generated by the radiation sources into linearly polarized sub-beams, and at least one polarization-rotating element, the polarizing system comprising at least one optically transparent plate having a refractive index n.sub.0 and a first face and a second face, while at least one of said faces is provided with an optically thin layer having a refractive index n.sub.1 which is larger than n.sub.0, the light path of at least one of the sub-beams incorporating a reflector for reflecting said sub-beam into the same direction of propagation as that of the other sub-beam, and the chief ray of each said beam and the normal on the plate enclosing an angle which is substantially equal to the Brewster angle which holds for the interface between the optically thin layer and a medium surrounding the polarizing system.