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:
Mar. 13, 2012
Filed:
Mar. 29, 2010
Shinichiro Saito, Utsunomiya, JP;
Nobuyuki Miyazawa, Utsunomiya, JP;
Tomonori Kimura, Utsunomiya, JP;
Shinichiro Saito, Utsunomiya, JP;
Nobuyuki Miyazawa, Utsunomiya, JP;
Tomonori Kimura, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens system, in which chromatic aberration, spherical aberration, and coma may be excellently corrected in a balanced manner so as to obtain excellent optical performance over an entire zoom range, includes, in order from an object side to an image side: a first lens unit having a positive refractive power; a second lens unit having a negative refractive power; and a rear lens group including a lens unit having a positive refractive power, in which: at least one of the first lens unit and the second lens unit is moved for zooming so that an interval therebetween at a telephoto end is larger than an interval at a wide angle end; the first lens unit includes at least one negative lens; and an Abbe number (νd) and a partial dispersion ratio (θgF) of a material of the at least one negative lens are appropriately set.