| 摘要 |
PROBLEM TO BE SOLVED: To obtain an illumination device constituted so that the utilizing efficiency of light and the polarization conversion efficiency thereof are enhanced and a projection type display device constituted so that a high-luminance projected video can be obtained. SOLUTION: A light source device is provided with a light source 101, a rotary elliptical mirror 102 obtained by arranging the light source 101 at an almost focusing position being the far-thest from a surface to be irradiated and a spherical mirror 103 having an aperture at a center obtained by arranging the light source 101 at an almost central position. Then, a plane-concave lens 104, a cholesteric liquid crystal layer 105 and a 1/4 wavelength optical phase plate 106 are arranged in turn between the light source device and an object to be irradiated so as to enhance condensing efficiency and the polarization conversion efficiency. |
