| 摘要 |
PROBLEM TO BE SOLVED: To realize an image projection device having a projection optical system whose performance is stable in terms of tolerance and assembly while the projection distance is shortened. SOLUTION: The image projection device irradiates a light valve with illumination light and enlarges and projects an image, formed by the light valve according to a modulated signal, on a screen 16 by the projection optical system, which comprises a 1st projection optical system which has positive power and a 2nd projection optical system 13 including a refraction optical system 14 and a reflection optical system (reflecting surface) 15 having negative diverging power; and the 2nd projection optical system comprises at least three or more surfaces, i.e. a 1st transmission surface 14a and a 2nd transmission surface 14b of the refraction optical system and the reflecting surface 15, and the projection image from the 1st projection optical system is transmitted through the 1st transmission surface of the 2nd projection optical system, reflected by the reflecting surface to have its optical path bent, and transmitted through the 2nd transmission surface to be projected on the screen. COPYRIGHT: (C)2004,JPO&NCIPI
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