| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical device capable of preventing a projected picture from getting out of focus or being deformed even in the case of projecting the picture to a screen disposed upper than a set position. SOLUTION: A reflection mirror 15 is disposed at the inclination of 45 deg. to the screen 36, and a specified angleθ3 formed by a projection axis TA with the projection surface of the screen 36 is set to an angle smaller than 90 deg.. Then, a condensing lens 12 and a projection lens 14 are disposed so that both of an angleθ1 formed by an axis OA1' perpendicular to the optical axis OA1 of the lens 12 with the projection axis TA and an angleθ2 formed by the axis OA2' perpendicular to the optical axis OA2 of the lens 14 with the projection axis TA may be the specified angleθ3 .
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