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:
Jun. 03, 2008
Filed:
Sep. 08, 2005
Manabu Hakko, Utsunomiya, JP;
Koshi Hatakeyama, Tokyo, JP;
Manabu Hakko, Utsunomiya, JP;
Koshi Hatakeyama, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A zoom optical system includes in order from a reduction side to a magnification side: a first lens unit having a positive optical power; a second lens unit having a negative optical power; a third lens unit having a positive optical power; and a fourth lens unit having a positive optical power, wherein respective intervals between the above described first, second, third and fourth lens units vary during zooming; a magnification-side conjugate position with respect to a reduction-side conjugate position and a position of a pupil of the above described zoom optical system with respect to a reduction-side conjugate position are substantially immobile respectively across the entire zooming range, and the above described fourth lens unit moves toward the magnification side and an interval between the above described first lens unit and the above described fourth lens unit increases during zooming from a wide-angle end to a telephoto end.