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:
Sep. 01, 2009
Filed:
Feb. 12, 2008
Yusuke Kusaka, Utsunomiya, JP;
Yusuke Kusaka, Utsunomiya, 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 positive refractive power configured not to move for zooming, a second lens unit having a negative refractive power configured to move during zooming, a third lens unit having a positive refractive power configured to move during zooming, and a fourth lens unit having a positive refractive power configured not to move for zooming. The third lens unit includes a positive lens, a negative lens, and a diffractive optical element. A focal length of the third lens unit (fc), a focal length of the diffractive optical element (fdoe), a focal length at a wide angle end of the zoom lens (fW), and a focal length at a telephoto end of the zoom lens (fT) satisfy the following conditions:0.35<fc/√{square root over ((fW·fT))}<0.81, and45<fdoe/fc<300.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile