| 摘要 |
PROBLEM TO BE SOLVED: To provide such an illuminator that the size of a light source image formed on a 2nd fly-eye surface is made smaller like a point light source by much more improving the parallelism of luminous flux made incident on an integrator optical system. SOLUTION: Parallel beams reflected by a rotating parabolic mirror 4 are emitted toward the integrator optical system 5 through a window 14 formed of the non mirror surface of a plane mirror 12, while light emitted from a light source 3 and not entering the mirror 4 directly is reflected by the mirror 12 made orthogonal to the optical axis of the parallel beams, returned to the mirror 4 again and reflected thereby, and passes through a focal position and is reflected by the mirror 4 again so as to be emitted as the parallel beams, whereby almost all the luminous flux being the light source light is efficiently utilized, and also the parallelism of the luminous flux emitted toward the optical system 5 is not lowered.
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