| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device which is capable of suppressing the increase of a set external shape size or the like and enhancing contrast and is superior in silence, and a projection display device. SOLUTION: A diaphragm device 105 opening/closing concentrically with an optical axis is disposed in a middle position between a first MLA 104 and a second MLA 106 of an illuminating optical device 109 and is continuously variably operated so as to raise/reduce a diaphragm aperture ratio in the case of a high/low average luminance level of an image signal to always give the most suitable diaphragm aperture in accordance with the average luminance level and is controlled so as to give a maximum illumination F number in the black side and is controlled so as to give a minimum illumination F number and 100% diaphragm aperture ratio in the white side and has a structure of not giving 0% aperture ratio, and surfaces of diaphragm blades are finished by gloss plating and are provided with projections capable of point contact in overlapping areas of the blades, and a galvanometer 400 is disposed on the exit surface side of a light source part 101. COPYRIGHT: (C)2006,JPO&NCIPI
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