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. 14, 1999
Filed:
Mar. 27, 1998
Yasuyuki Tomita, Kawasaki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom lens including, in succession from the object side, a first positive lens unit (focal length f1), a second negative lens unit, a third lens unit, and a fourth positive lens unit, the second and third lens units moving for zooming, the first lens unit having, from the object side, a front lens subunit (focal length f11) fixed during focusing and a rear lens subunit (focal length f12) movable toward the object side for focusing on an infinity object to a short distance object, the front lens subunit having a cemented lens comprising a first negative lens (refractive power N111, Abbe number .nu.111) and a second positive lens (refractive power N112, Abbe number .nu.112) cemented together, the rear lens subunit having first and second positive lenses, wherein, where Ri is the radius of curvature of the ith lens surface from the object side:
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile