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. 02, 2013
Filed:
Jan. 15, 2010
Masao Hori, Utsunomiya, JP;
Youtarou Sanjou, Utsunomiya, JP;
Masao Hori, Utsunomiya, JP;
Youtarou Sanjou, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A zoom lens system includes, in order from object-side to image-side a positive first lens unit, a second negative lens unit, a third lens unit, and a fourth positive lens unit. The fourth unit includes a front subunit having positive power and a rear subunit having positive power. The following conditions are satisfied: −2.100×100.693; 0.555<0.900; 0.8<(ν)/(ν)<4.0; 0.8<|{(θfn−θfp)/(νfp−νfn)}/{(θrn−θrp)/(νrp−νrn)}|, where vd and θgF indicate Abbe number and partial dispersion ratio of a lens included in the rear subunit, respectively, and where νfp, θfp, νfn and θfn indicate averages of Abbe number and partial dispersion ratio of positive lenses and averages of Abbe number and partial dispersion ratio of negative lenses included in the front subunit, respectively; νrp, θrp, νrn and θrn indicate averages of Abbe number and partial dispersion ratio of positive lenses and averages of Abbe number and partial dispersion ratio of negative lenses included in the rear subunit, respectively.