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:
Jul. 24, 1990
Filed:
Jan. 26, 1988
Applicant:
Inventor:
Hiroshi Yamashita, Kawasaki, JP;
Assignee:
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
369 32 ;
Abstract
A position-detecting device comprising a scale, a first photo-interrupter, and a second photo-interrupter. The scale is attached to a movable member, and has a plurality of slits arranged at regular intervals. Each photo-interrupter includes a light source and a light detector, which are located at opposing sides of said scale, respectively. The first and second photo-interrupters are spaced apart such that when the scale moves, they generate, respectively, a first signal and a second signal which have a phase difference of .pi./2. These signals are processed, thereby to determine the position of the movable member with high accuracy.