| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-angle projection zoom lens which is improved in brightness, achieves a wide angle of view while maintaining favorable optical performance, and achieves compactness, and simplifies eccentricity adjustment for aspheric lenses. SOLUTION: The wide-angle projection zoom lens includes, in order from the magnification side: a first group G<SB>1</SB>that remains stationary during zooming and has a negative refractive power; second to fourth groups G<SB>2</SB>to G<SB>4</SB>that are movable independently from each other during zooming; a fifth group G<SB>5</SB>that remains stationary during zooming and has a positive refractive power. The projection zoom lens is configured to be telecentric on the reduction side. The first group G1 includes five lenses (Lenses L<SB>1</SB>to L<SB>5</SB>) having negative, negative, negative, positive, negative refractive powers. The lenses L<SB>1</SB>and L<SB>5</SB>are formed as aspheric lenses made of plastic. During zooming from the wide-angle end to the telephoto end, the first group G<SB>1</SB>and the fifth group G<SB>5</SB>remain stationary, and the second, third, and fourth groups G<SB>2</SB>, G<SB>3</SB>, and G<SB>4</SB>are movable in a direction of the optical axis Z so as to narrow a space between the first group G<SB>1</SB>and the second group G<SB>2</SB>and widen a space between the fourth group G<SB>4</SB>and the fifth group G<SB>5</SB>. COPYRIGHT: (C)2011,JPO&INPIT
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