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:
May. 21, 2013
Filed:
Jan. 19, 2011
Yasushi Yoshida, Fukuoka, JP;
Shirou Yoshidomi, Fukuoka, JP;
Jiro Muraoka, Fukuoka, JP;
Kabushiki Kaisha Yaskawa Denki, Kitakyushu-Shi, JP;
Abstract
An encoder includes a disk including a first track and a second track each being ring-shaped and provided with a rotary grating, and a first detector and a second detector that are fixedly disposed so as to respectively face the first track and the second track each provided with a fixed grating that detects diffracted interfering light. A plurality of slits of the first track are formed as curved slits. The first detector facing the first track is disposed at a position where a tangent of each of the slits included in the diffraction grating of the first track becomes parallel to a tangent of each of the slits included in the diffraction grating of the second track at a position where the second detector faces the second track.