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:
Jul. 15, 2014
Filed:
Feb. 24, 2012
Masaru Sakamoto, Utsunomiya, JP;
Masaru Sakamoto, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A zoom lens includes, in order from object side, a positive first lens unit which does not move for varying magnification, a negative second lens unit which moves for varying magnification, a negative third lens unit which moves for varying magnification, and a positive fourth lens unit which does not move for varying magnification, wherein the first lens unit includes a positive lens which satisfies the following conditions: 70<νp<85; 2.31<Np+0.01×νp<2.58; and 1.6<Np<1.85, where Np is refractive index of the positive lens, and νp is Abbe constant of the positive lens, and 1.25<|fp/fna|<1.7 is satisfied, where fp is focal length of the positive lens, and fna is combined focal length of negative lenses in the first lens unit defined by the equation: where n is a number of the negative lenses in the first lens unit, and fni is focal length of the i-th negative lens.