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:
Oct. 14, 2014
Filed:
Jan. 24, 2013
Canon Kabushiki Kaisha, Tokyo, JP;
Akihiko Yuki, 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 negative refractive power, a second lens unit having positive refractive power, and a third lens unit having positive refractive power. A distance between every adjacent ones of the first to third lens units varies during zooming. The second lens unit includes, in order from the object side to the image side, a positive lens and a cemented lens in which a positive lens and a negative lens are cemented. A focal length (f) of the second lens unit, a focal length (fT) of the entire zoom lens at a telephoto end, and an average refractive index (Npave) of materials of the positive lenses included in the entire zoom lens are appropriately set.