摘要 |
PROBLEM TO BE SOLVED: To provide a compact variable power optical system which has high optical performance and can be mounted on a cellular phone and a personal digital assistant, while restraining rise in cost rise, and to provide an imaging lens device and digital equipment on which the imaging lens device is mounted. SOLUTION: The variable power optical system has a 1st lens group having negative optical power as a whole and 2nd and 3rd lens groups having positive optical power as a whole in order from an object side, and they are all constituted to move in an optical axis direction at varying of power. The 1st lens group is constituted of a biconcave lens, having negative optical power and a positive meniscus lens convex to the object side, in this order from the object side, and the 2nd lens group is constituted of a doublet constituted, by arranging and bonding a biconvex lens having positive optical power and a biconcave lens having negative optical power in order from the object side; then the 3rd lens group is constituted of a biconvex lens having positive optical power. The 1st and the 5th lenses are both-surface aspherical lenses formed of resin, and the 3rd and the 4th lenses are one-surface aspherical lenses. COPYRIGHT: (C)2006,JPO&NCIPI
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