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:
Nov. 24, 2015
Filed:
Apr. 12, 2013
Canon Kabushiki Kaisha, Tokyo, JP;
Yotaro Sanjo, Utsunomiya, JP;
CANON KABUSHIKI KAISHA, , JP;
Abstract
A zoom lens includes, in order from object side: a positive first unit immovable for zooming; a negative second unit moving during zooming; a third unit moving during zooming; a stop; and a positive fourth unit immovable for zooming. The first unit includes, in order from object side, a fixed negative front first unit, a positive middle first unit moving for focusing, and a fixed positive rear first lens unit. Each of the front first and the second units includes at least one positive lens and two negative lenses. Average of Abbe constants and average of partial dispersion ratios of positive lenses in the front first unit, average of Abbe constants and average of partial dispersion ratios of negative lenses in the front first unit, combined focal length of the positive lenses in the front first unit and focal length of the front first unit are appropriately set.