| 摘要 |
PROBLEM TO BE SOLVED: To effectively shield undesired light without limiting the shape of a lens. SOLUTION: As for the projecting lens for a front projection type projector, masks 7 and 8 for shielding an undesired optical path through an opening 11 which is formed suitable to the shape of a projected image are installed. Besides, means 1a, 2a, 7a, 7b and 8a for changing the shape of the opening part of the mask in accordance with a zooming operation are arranged. The masks are arranged near a front spherical lens.
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