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:
Aug. 21, 2001
Filed:
Oct. 27, 1999
Michiharu Aratani, Kawasaki, JP;
Hiroshi Nakanishi, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An image pickup optical system has an optical element of a transparent, optical material including an entrance surface, at least one reflective surface, and an exit surface. The optical element has an optical power, the image pickup optical system has an image pickup element including a plurality of pixels. On the image pickup element an image is formed by light from an object through the optical element. The optical material is a material having an index change amount &Dgr;n from an absolute dry condition at the temperature of 50° C. to saturation under a circumstance of the temperature being 50° C. and the humidity being 90%, the index change amount &Dgr;n satisfying the following condition: &Dgr;n≦F&dgr;r,/(2f,L) where F is the F-number of the image pickup optical system, f is the focal length of the image pickup optical system, &dgr; is the pitch of the pixels of the image pickup element, L is the optical path length of the optical element along the reference axis, and r,is half of the length of the optical element along a direction perpendicular to a plane including the reference axis.