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:
Nov. 22, 1988
Filed:
Apr. 08, 1986
Toshitsugu Ueda, Tokyo, JP;
Fusao Kohsaka, Tokyo, JP;
Toshio Iino, Tokyo, JP;
Hiroshi Nakayama, Tokyo, JP;
Yokogawa Electric Corporation, Tokyo, JP;
Abstract
An encoder device of the absolute position type for outputting a shift position or angle of rotation relative to the absolute position. The device comprises a code plate having first and second grid patterns wherein information is stored as 1 or 0 in a periodic manner at pitches slightly different from each other; first and second sensory arrays for detecting the first and second grid patterns; driving means for driving the sensors relative to the grid patterns and for obtaining an alternating signal from each array; and computation means for measuring the phase angle of the alternating signal from each array, and the phase angle difference therebetween and for calculating the position using such phase angles. Advantageously, the invention is suitable for miniaturization due to its simplicity, relaibility, and efficiency.