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. 06, 2005
Filed:
May. 18, 2001
Jun Kawakami, Tokyo, JP;
Hisashi Shiozawa, Tokyo, JP;
Jun Kawakami, Tokyo, JP;
Hisashi Shiozawa, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Both the optical distance of the detected-light light path and the optical distance of the reference-light light path are simultaneously varied according to respective specified patterns, so that differences are created between the period of variation in the intensity of the required signal component (in the interference signals) and the periods of variation in the intensities of the coherent noise components. When the modulation scanning procedure is performed, the phase difference between the detected light and reference light in a specified state is determined as shape information for the above-mentioned detected surface on the basis of the interference signals output from the light-receiving element. As a result, it is possible to securely reduce the effects of coherent noise components generated as a result of the interference of specified noise light that has passed through at least portions of the detected-light light path and reference-light light path with the detected light or reference light.