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:
Aug. 23, 2011
Filed:
Apr. 01, 2009
Kyoichi Miyazaki, Osaka, JP;
Katsu Yamada, Osaka, JP;
Takuya Imaoka, Kanagawa, JP;
Masaki Sampei, Hyogo, JP;
Kyoichi Miyazaki, Osaka, JP;
Katsu Yamada, Osaka, JP;
Takuya Imaoka, Kanagawa, JP;
Masaki Sampei, Hyogo, JP;
Panasonic Corporation, Osaka, JP;
Abstract
A zoom lens system is provided that includes a compactly constructed focusing lens unit and that has a suppressed change in the image magnification at the time of movement of a focusing lens unit. The zoom lens system according to the present invention comprises: a positive lens unit that is arranged on an object side relative to the aperture diaphragm; a negative lens unit that is arranged on an image side relative to the positive lens unit and on an object side relative to the aperture diaphragm; and a focusing lens unit that is arranged in an optical path between the negative lens unit and the aperture diaphragm. The zoom lens system satisfies the condition (4): 1.20<β/β<4.50 (here, f/f>3.0, β(β): a composite focal length of the focusing lens unit and the negative lens unit in an infinity in-focus condition at a telephoto (wide-angle) limit when the focusing lens unit has negative optical power, or a lateral magnification of the negative lens unit at a telephoto limit in an infinity in-focus condition when the focusing lens unit has positive optical power, f: a focal length of the entire system at a telephoto limit, f: a focal length of the entire system at a wide-angle limit.