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:
Mar. 12, 1991
Filed:
May. 03, 1989
Koh Ishizuka, Urawa, JP;
Tetsuharu Nishimura, Kawasaki, JP;
Satoshi Ishii, Tokyo, JP;
Yoichi Kubota, Kawasaki, JP;
Masaaki Tsukiji, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An encoder having a long length measuring stroke with a simple construction is provided. The encoder comprises a scale formed with a periodic lattice pattern, first and second reading heads arranged along a moving direction of the scale for reading the scale, and an adder for adding output signals from the first and second reading heads. The encoder further has adjusting mechanism for adjusting such that the phase difference between the output signals from the first and second reading head becomes zero. A continuous periodic signal can be always accurately obtained independently of the position of the scale.