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:
Jan. 02, 1996
Filed:
Jun. 04, 1993
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An encoder capable of detecting movement information on a moving body with high accuracy without being affected by environmental changes, wherein movement information on a moving body is detected by causing a luminous flux to impinge upon a first scale section of an optical scale which is provided on the moving body and which consists of gratings of a fixed pitch, causing the luminous flux to impinge upon a second scale section of the optical scale, and receiving the luminous flux which has undergone light modulation at the second scale section, and wherein a light adjustment device for intercepting or attenuating a +1st order or -1st order diffracted ray of diffracted rays of light from the first scale section is provided in the optical path extending from the first scale section, an optical image having an intensity distribution of the same grating pitch as the first scale section being formed on the second scale section mainly by the zero order and the -1st order diffracted rays or by the zero order and the +1st order diffracted rays.