The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 2008
Filed:
Aug. 28, 2006
Toshiki Nakamura, Saitama, JP;
Takayuki Ito, Saitama, JP;
Toshiki Nakamura, Saitama, JP;
Takayuki Ito, Saitama, JP;
Hoya Corporation, Tokyo, JP;
Abstract
A zoom lens system includes a negative first lens group, a positive second lens group, and a positive third lens group functioning as a focusing lens group, in this order from the object. Upon zooming from the short focal length extremity to the long focal length extremity, the distance between the negative first lens group and the positive second lens group decreases, and the distance between the positive second lens group and the positive third lens group increases. The positive third lens group includes cemented lens elements having a positive lens element and a negative lens element. The zoom lens system satisfies the following condition:0.2<  (1) wherein fdesignates the focal length of the positive lens element of the positive third lens group; and fdesignates the focal length of the negative lens element of the positive third lens group.