Patent ID: 8851681
Filing Date: 2014-10-07
Classification: G02B,G03B,H04N

Abstract:
1. An illumination device comprising: a light source section having plural kinds of light sources, the light sources emitting light beams having different wavelengths; a parallelizing optical system for parallelizing each of the light beams entered from the light sources, and for allowing each of the parallelized light beams to exit therefrom; a light path unifying optical system for unifying the parallelized light beams exited from the parallelizing optical system into a single light path; an expanding optical system for expanding a beam diameter of each of the parallelized light beams unified into the single light path, and for allowing each of the expanded and parallelized light beams to exit therefrom; a uniformizing optical system for uniformizing an in-plane intensity distribution in each of the expanded and parallelized light beams exited from the expanding optical system; and a retarder, wherein each of the light beams exited from the light sources exhibit a far-field pattern having a shape with an in-plane anisotropy, wherein directions of major axes of the far-field patterns in the light beams exited from the light sources substantially coincide with one another, wherein the light beams exited from the light sources includes two kinds of light beams, one of the two kinds of light beams being polarized in a first polarization direction and the other being polarized in a second polarization direction, and wherein the retarder allows the first and the second polarization directions to be varied and to be brought closer to each other.