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. 10, 2009
Filed:
Oct. 09, 2007
Hiroyuki Hamano, Koga, JP;
Hiroyuki Hamano, Koga, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens performs zooming by moving a plurality of lens units, and includes a front lens unit disposed on an object side of an aperture stop and at least one diffractive optical part having positive power, and a rear lens unit disposed on an image side of the aperture stop including at least one refractive optical element made of a solid material and having a positive refractive power. When νd and θgF are the Abbe number and the partial dispersion ratio, respectively, of the material of the refractive optical element, and fD and fN are the focal lengths of the diffractive optical part and the refractive optical element, respectively, in air, the following expressions are satisfied:0.755<θ−(−1.665×10+5.213×10−5.656×10)<1.011, and80<<800.