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, 1996
Filed:
Jan. 31, 1995
Koh Ishizuka, Ohmiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An apparatus for detecting information as for the rotation of a scale having a diffraction grating arranged thereon along a direction of detection of the rotation is constituted by a light source portion for irradiating a light beam onto a first point on the diffraction grating of said scale wherein said light source portion emitting two diffracted lights having a predetermined order from the first point by the irradiation of the light beam, a transparent substrate to be parallelly arranged in the vicinity of the surface of said scale and having a plurality of optical elements arranged thereon, said plurality of optical elements directing the two diffracted lights of the predetermined order to a second point other than said first point on the diffraction grating of said scale and a photo-detector for detecting an interference light beam of the diffracted lights generated out of said second point on which the two diffracted lights of the predetermined order are incident whereby the information on the rotation of said scale relative to the photo-detector is detected by the photo-detection by said photo-detector.