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:
May. 13, 2014
Filed:
Nov. 10, 2011
Yoshiyuki Kuramoto, Utsunomiya, JP;
Yoshiyuki Kuramoto, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of calculating a geometrical distance of a test optical path on the basis of interfering a test beam and a reference beam includes an optical-path-length calculating step of calculating an optical path length of the test optical paths having different wavelengths by using the interfering beam having mutually different wavelengths, a refractive-index calculating step of calculating the refractive index of the test optical path on the basis of the optical path length of the test optical path calculated by the optical-path-length calculating step, a smoothing step of smoothing a plurality of refractive indices acquired by repeating the optical-path-length calculating step and the refractive-index calculating step to calculate a smoothed refractive index, and a geometrical distance calculating step of calculating the geometrical distance of the test optical path on the basis of the smoothed refractive index calculated by the smoothing step.