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:
Mar. 25, 2014
Filed:
May. 23, 2012
Hiroyuki Hamano, Saitama, JP;
Arata Sato, Utsunomiya, JP;
Ken Wada, Sakura, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens includes, a first lens unit having positive refractive power, a second lens unit having negative refractive power, a third lens unit having positive refractive power, and a fourth lens unit having positive refractive power. All of the lens units are moved during zooming from a wide-angle end to a telephoto end. An aperture stop is arranged on the image side of the third lens unit. A distance T23 from a lens surface closest to the image side in the second lens unit to a lens surface closest to the object side in the third lens unit when the zoom lens is at the telephoto end, a focal length fT of the entire zoom lens at the telephoto end, and focal lengths f1, f2, and f3 of the first, second, and third lens units, respectively, are set based on predetermined mathematical conditions.