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:
Mar. 07, 2000
Filed:
Jan. 07, 1998
Hajime Ichikawa, Kanagawa-ken, JP;
Takahiro Yamamoto, Kanagawa-ken, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A non-spherical surface shape measuring device and method that measures the shapes of object surfaces that have rotationally symmetrical non-spherical surface shapes on the basis of relative deviation values from the shape of a reference surface, the non-spherical surface shape measuring device includes a measuring means for obtaining relative deviation values between a reference surface and an object surface by measuring corresponding sampling points on the surfaces of the reference surface and the object surface and storing predetermined coefficients of variables prior to measurement. A first operating means approximates the partial differential coefficients for the predetermined variables and models the relative displacement, between the object surface and the reference surface and the XY-coordinates of the sampling points, into functional equivalents of the partial differential coefficients. A second operating means approximates the relative displacement between the object surface and the reference surface and a third operating means corrects the relative deviation values according to the relative displacement approximated by the second operating means.