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:
Sep. 24, 2013
Filed:
Sep. 15, 2009
Takeshi Suzuki, Utsunomiya, JP;
Yoshiyuki Kuramoto, Utsunomiya, JP;
Takeshi Suzuki, Utsunomiya, JP;
Yoshiyuki Kuramoto, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A measurement apparatus comprises a mirror configured to reflect test light which passes through an optical system, an interferometer unit which includes an image sensor and is configured to form an interference fringe on an image sensing plane of the image sensor by reference light and the test light reflected by the mirror, and a controller configured to control the interferometer unit, and to compute a numerical aperture of the optical system based on the interference fringe captured by the image sensor, wherein the controller is configured to compute a numerical aperture NA of the optical system by multiplying a quotient ΔNA/ΔR, describing a change ΔNA in numerical aperture NA of the optical system with respect to a change ΔR in pupil radius R of the optical system in the image sensing plane, by the pupil radius R of the optical system in the image sensing plane.