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:
Oct. 16, 2001
Filed:
Jan. 15, 1998
Jin Tachikawa, Hino, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A machining device for illuminating a periodic pattern of a mask with coherent light emitted from a light source and projecting the image of the pattern onto a workpiece through an optical system. The optical system includes first and second optical members. The second optical member, which is positioned at an area where diffracted light rays of different orders out of the diffracted light rays generated by the mask are superimposed, employs an optical material having a smaller variation in an optical path length arising from light absorption than an optical material of the first optical member, which is positioned at an area where diffracted light rays of different orders are not superimposed.