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. 30, 2012
Filed:
Jun. 09, 2011
Masakazu Kodaira, Utsunomiya, JP;
Masakazu Kodaira, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A zoom lens, including: a first lens unit and a second lens unit, in which the first lens unit includes: a first lens sub unit which does not move; a second lens sub unit which moves for focusing; and a third lens sub unit which does not move; and in which the following expression is satisfied, −2.27×10<(θp−θna)/(νp−νna)<−1.9×10, where νna and θna represent an average value of an Abbe number ν and an average value of a partial dispersion ratio θ of negative lenses included in the first lens sub unit, respectively, νp and θp represent an Abbe number and a partial dispersion ratio of a positive lens having a smallest Abbe number among lenses constituting the first lens sub unit, respectively, θ=(Ng−NF)/(NF−NC), and Ng, NF and NC denote refractive indexes at the g-line, the F-line and a C-line, respectively.
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