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:
Feb. 01, 2000
Filed:
Feb. 26, 1998
Nobuaki Ueki, Omiya, JP;
Fuji Photo Optical Co., Ltd., Saitama, JP;
Abstract
While the three-flat method is used as background art, a technique for analyzing the difference between two planes by approximating it with symmetry power series polynomials are employed, and measurement is effected at two positions where the reference surface and the sample surface are in a predetermined reference rotation state and where they are rotated from each other by 90 degrees from the former state; whereby the approximate surface form of the whole plane can be determined by a very simple arithmetic operation with a high accuracy. Of three glass sheets, different pairs of two glass sheets 53 and 54 are successively selected three times. The difference between two surfaces to be measured in each pair of the two glass sheets 53 and 54 is measured at a first position where, with respect to one glass sheet 53, the other is set at a predetermined rotational position; and a second position where the two sheets are rotated from each other by 90 degrees from the first position. Then prepared are relational expressions to which sixth-order Zernike polynomials approximating the difference between the surfaces to be measured is applied. These relational expressions are operated so as to determine the form of the surface to be measured in each of the glass sheets.