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:
Dec. 31, 2013
Filed:
Jul. 05, 2011
Haruhiko Horiguchi, Tokyo, JP;
Haruhiko Horiguchi, Tokyo, JP;
Canon Kabushiki Kaisha, , JP;
Abstract
An absolute encoder () includes a scale portion () movable along with the object and including first and second track () having first and second slits (), a light source () that illuminates a light onto the first and second slits, a first detector () that detects a first signal obtained from a light from the first slit, a second detector () that detects a second signal obtained from a light from the second slit, and a calculator () that calculates an absolute position of an object based on the first and second signals. The second slit is formed so that a reflected light intensity or a transmitted light intensity is different in accordance with a position in a moving direction of the scale portion. The calculator obtains an upper-level signal, a middle-level signal, and a lower-level signal to calculate the absolute position.