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:
May. 08, 2007
Filed:
Mar. 09, 2005
Shinji Yamasaki, Tochigi-ken, JP;
Takashi Sudo, Tochigi-ken, JP;
Shinji Yamasaki, Tochigi-ken, JP;
Takashi Sudo, Tochigi-ken, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Provided is a projection lens, including: a plurality of moving lens units that move on an optical axis for zooming; and a plurality of plastic lenses containing plastic, in which when a focal distance of an i-th positive lens from a predetermined plane side of N positive lenses of the plurality of plastic lenses is given by fpi, a focal distance of a j-th negative lens from the predetermined plane side of M negative lenses of the plurality of plastic lenses is given by fnj, and fp and fn are defined by (N and M each are a natural number, that is, an integer equal to or larger than 1), −0.56<fn/fp<−0.05 is satisfied.