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:
Jun. 23, 2015
Filed:
Feb. 25, 2013
Canon Kabushiki Kaisha, Tokyo, JP;
Hiroshi Osawa, Utsunomiya, JP;
CANON KABUSHIKI KAISHA, , JP;
Abstract
The present invention provides a measurement apparatus which measures a measurement surface based on an interference signal obtained by causing measurement light reflected by the measurement surface and reference light reflected by a reference surface to interfere with each other, the apparatus including an interference optical system including a lens for focusing the measurement light to be incident on the measurement surface, and configured to cause the measurement light and the reference light to interfere with each other, and an adjusting device configured to adjust a focusing state of the measurement light focused by the lens such that a measurement point on the measurement surface positions within a range of a depth of focus of the lens, wherein the interference signal is obtained with the focusing state adjusted by the adjusting device.