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:
Dec. 30, 2008
Filed:
Feb. 27, 2007
Tomowaki Takahashi, Yokohama, JP;
Tomowaki Takahashi, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Projection-optical systems are disclosed that have a large image-side NA of, e.g., ≧0.45, and that allow inspection for surface-shape errors of reflecting surfaces with prescribed precision. A first reflective image-forming optical system forms an intermediate image of a first surface. A second reflective image-forming optical system forms a reduced image, on a second surface, of the intermediate image. The first reflective image-forming optical system has a first concave mirror, a second convex mirror, a third mirror, and a fourth concave mirror. The second reflective image-forming optical system has a fifth concave mirror, a sixth mirror, a seventh convex mirror, and an eighth concave mirror. If the absolute value of the center radius of curvature of the reflective surface of the second mirror is RM, and the maximum object height on the first surface is H, then the condition 1<RM/H<6 is satisfied.
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