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:
Feb. 04, 2014
Filed:
Jun. 04, 2012
Akihisa Horiuchi, Utsunomiya, JP;
Akihisa Horiuchi, Utsunomiya, 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. The first to fourth lens units move during zooming. The first lens unit includes a cemented lens obtained by cementing negative and positive lenses, the second lens unit includes negative, negative, and positive lenses, the third lens unit includes positive and negative lenses, and the fourth lens unit includes a positive lens. Movement amounts Mand Mof the first and third lens units, respectively, during zooming from the wide-angle end to the telephoto end and focal lengths fand fof the first and third lens units, respectively, are appropriately set based on predetermined mathematical conditions.