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:
Apr. 09, 2013
Filed:
Mar. 02, 2011
Takamasa Sasaki, Utsunomiya, JP;
Yoshiyuki Kuramoto, Utsunomiya, JP;
Takamasa Sasaki, Utsunomiya, JP;
Yoshiyuki Kuramoto, Utsunomiya, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A lightwave interference measurement apparatus includes a phase detector configured to detect a phase of a signal of an interference between light from a distance-measurement light source and reflected on a reference surface and light from the distance-measurement light source and reflected on a target surface, an intensity detector configured to detect an intensity of light from a non-distance-measurement light source having a wavelength different from that of the distance-measurement light source and reflected on the reference surface and an intensity of light from the non-distance-measurement light source and reflected on the target surface, and an analyzer configured to calculate a geometric distance based on an optical path length calculated from the phase and a wavelength of the distance-measurement light source, and an average value of a vapor pressure distribution between the target surface and the reference surface calculated from intensity information of the light from the non-distance-measurement light source.