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:
Aug. 04, 2015
Filed:
Apr. 23, 2012
Akihiro Kuroda, Kanagawa, JP;
Akihiro Kuroda, Kanagawa, JP;
DMG MORI SEIKI CO., LTD., Yamatokoriyama-shi, JP;
Abstract
A displacement detecting device includes: a diffraction grating having a relief shape; an irradiation optical system adapted to irradiate two beams onto the diffraction grating as p-polarized light; a reflection optical system adapted to reflect two first diffracted lights generated when the two beams is diffracted by the diffraction grating, and cause the first diffracted lights to be incident again on the diffraction grating as p-polarized light so as to generate two second diffracted lights; an interference optical system adapted to cause the two second diffracted lights to interfere with each other to obtain interference light; a light receiving section adapted to receive the interference light; and a position information detecting section adapted to detect position information of the diffraction grating based on an interference signal. The period of the relief of the diffraction grating is no more than 1.5 times the wavelength of coherent light.