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. 22, 2011
Filed:
Jul. 29, 2009
Takashi Okada, Saitama, JP;
Takashi Okada, Saitama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens includes, in order from an object side to an image side, a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, a third lens unit having a negative refractive power, and a fourth lens unit having a positive refractive power. In the zoom lens, an interval between every adjacent ones of the first through fourth lens units varies during zooming, the second lens unit includes at least one negative lens, and the third lens unit includes at least one positive lens. An Abbe number and a relative partial dispersion of a material of the at least one negative lens (νd2N, θgF2N) and an Abbe number and a relative partial dispersion of a material of the at least one positive lens (νd3P, θgF3P) are appropriately set.