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. 16, 1997
Filed:
Mar. 13, 1995
Mitsuru Yanagisawa, Tokyo, JP;
Takumi Fukuda, Tokyo, JP;
Copal Company Limited, Tokyo, JP;
Abstract
An absolute encoder is provided with a movable member, which may be a disc, a photodetector and a processing circuit. The movable member has a plurality of tracks T arranged from higher to lower orders, each track having a bright and dark pattern. The photodetectors A1-A4 receive a light through the bright and dark patterns to output triangular detection signals A1-A4 associated with the track T. The processing circuit processes the detection signals A1-A4 to produce bit signals P1-P3 which indicate a position of the movable member. The processing circuit is provided with an input unit 1, a comparator unit 2 and a logic unit 3. The input unit 1 receives the detection signals A1-A4 for producing a plurality of triangular wave signals having the same period but different phases. The comparator unit 2 comparatively processes the triangular wave signals with each other to produce a plurality of rectangular wave signals having different phases. The logic unit 3 logically processes the rectangular wave signals with each other to output at least three bit signals P1-P3 from one track.