| 摘要 |
PROBLEM TO BE SOLVED: To provide a telescopic zoom lens having five-group type constitution in which a positive 2nd group, a negative 3rd group and a negative 4th group are moved in variable magnification, suitable for a projection type display device using liquid crystal and having suitably corrected aberrations and a long focal distance and to provide the projection type display device using the zoom lens. SOLUTION: A negative 1st lens group G<SB>1</SB>for focusing an image at a fixed state in variable magnification, a positive 2nd lens group G<SB>2</SB>, a negative 3rd lens group G<SB>3</SB>and a negative 4th lens group G<SB>4</SB>which are moved with correlation in order to correct continuous variable magnification and image surface movement produced by the continuous variable magnification, and a positive 5th lens group G<SB>5</SB>fixed in variable magnification are successively arranged from the enlargement side. Not the wide angle end positions of the lens groups G<SB>2</SB>, G<SB>3</SB>but the telescopic end positions are arranged on the enlargement side and not the wide angle end position of the lens group G<SB>4</SB>but the telescopic end position is arranged on the reduction side. Each of conditional expressions -2.2<F<SB>1</SB>/F<-1.2 (1), 0.6<F<SB>2</SB>/F<1.1 (2), -15.0<F<SB>4</SB>/F<-1.5 (3), and 0.7<F<SB>5</SB>/F<1.2 (4) is satisfied. COPYRIGHT: (C)2005,JPO&NCIPI
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