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:
Oct. 23, 2009
Ko Ishizuka, Saitama, JP;
Ko Ishizuka, Saitama, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
A wavelength shift measuring apparatus of the present invention is a wavelength shift detection sensor (WLCD) which measures a shift of a wavelength of a light beam emitted from a light source, and includes a beam splitter (BS) splitting the light beam emitted from the light source into a plurality of light beams and to synthesize two light beams among the plurality of light beams to generate an interference light, a spacer member (SP) provided so that an optical path length difference of the two light beams split by the beam splitter (PBS) is constant, and a plurality of photoelectric sensors (PD) detecting the interference light generated by the beam splitter (BS). The plurality of photoelectric sensors (PD) output a plurality of interference signals having phases shifted from one another based on the interference light to calculate a wavelength shift using the plurality of interference signals.