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:
Jan. 09, 2007
Filed:
Sep. 02, 2004
Takahiro Sasaki, Tochigi, JP;
Takahiro Sasaki, Tochigi, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A projection optical system is provided for projecting a pattern on an object surface onto an image surface in a reduced size. The projection optical system has six reflective surfaces that include, in order of reflecting light from the object surface, a first reflective surface, a second convex reflective surface, a third convex reflective surface, a fourth reflective surface, a fifth reflective surface and a sixth reflective surface. An aperture stop is provided along an optical path between the first and second reflective surfaces. The following condition is met by the system, where Lis an interval between the object surface and the surface apex that is the closest to the object surface, and Lis an interval between the surface apex of the first reflective surface and the surface apex that is the closest to the object surface: