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. 17, 2009
Filed:
Feb. 25, 2008
Kenji Obu, Utsunomiya, JP;
Ken Wada, Shioya-gun, JP;
Takashi Okada, Utsunomiya, JP;
Yoshihisa Tashiro, Nikko, JP;
Kenji Obu, Utsunomiya, JP;
Ken Wada, Shioya-gun, JP;
Takashi Okada, Utsunomiya, JP;
Yoshihisa Tashiro, Nikko, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens system includes a first lens unit having a negative refractive power, at least one lens unit having a positive refractive power, and an optical element composed of a material having an Abbe number and a partial dispersion that satisfy a predetermined condition. The first lens unit, an aperture stop, and the at least one lens unit are arranged in this order from the object side to the image side. The zoom lens system performs zooming while changing the distance between the lens units. The focal length fof the optical element, the distance Lt from the aperture stop to the optical element in the telephoto end state, the overall length of the zoom lens system Tt in the telephoto end state, and the focal lengths fw and ft in the wide-angle end and telephoto end states are set at appropriate values.