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. 20, 2013
Filed:
Apr. 13, 2011
Kenji Shinohara, Utsunomiya, JP;
Kenji Shinohara, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens includes, in order from an object side to an image side, a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. The second lens unit and the fourth lens unit move during zooming. The third lens unit includes at least one positive lens and at least one negative lens. When Rnf and Rnr are radiuses of curvature of surfaces on the object side and the image side respectively of one negative lens of the second lens unit, Rpf and Rpr are radiuses of curvature on the object side and the image side respectively of one positive lens of the second lens unit, the following conditions are satisfied:3.4<()/()<4.4−0.7<()/()<−0.5.