| US 7,589,910 B2 | ||
| Zoom lens, camera, and personal digital assistant | ||
| Kazuyasu Ohashi, Funabashi (Japan) | ||
| Assigned to Ricoh Company, Ltd., Tokyo (Japan) | ||
| Filed on Jun. 29, 2007, as Appl. No. 11/771,300. | ||
| Claims priority of application No. 2006-182843 (JP), filed on Jun. 30, 2006; and application No. 2006-269663 (JP), filed on Sep. 29, 2006. | ||
| Prior Publication US 2008/0106799 A1, May 08, 2008 | ||
| Int. Cl. G02B 15/14 (2006.01) | ||
| U.S. Cl. 359—689 | 10 Claims |
| 1. A zoom lens, comprising:
a first lens group having a negative refracting power;
a second lens group having a positive refracting power;
a third lens group having a positive refracting power, the first lens group, the second lens group and the third lens group
disposed in order from an object side; and
an aperture stop disposed on the object side of the second lens group, moving with the second lens group,
wherein along with changing magnification from a wide-angle end toward a telephoto end, at least the first lens group and
the second lens group move, in a manner that a spacing between the first lens group and the second lens group decreases and
a spacing between the second lens group and the third lens group increases, and
the second lens group, comprising:
a first cemented lens having at least three pieces of lenses united; and
a second cemented lens having at least two pieces of lenses united.
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