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:
Dec. 01, 2009
Filed:
Dec. 05, 2008
Applicant:
Takayoshi Yokoyama, Utsunomiya, JP;
Inventor:
Takayoshi Yokoyama, Utsunomiya, JP;
Assignee:
Canon Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G02B 9/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
An optical system in which a maximum value of a height from an optical axis of a paraxial marginal ray closer to an expanded side than a point of intersection between an optical axis and a paraxial chief ray, includes a lens unit Lr including at least one refractive optical element Gn of a negative refractive power. In the optical system, νd (Gn) as an Abbe number of a material of the refractive optical element Gn, θgF (Gn) as a partial dispersion ratio regarding g and F-lines, FGn as a focal lengths of the refractive optical element Gn, and Fr as focal lengths of the lens unit Lr are set appropriately.