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. 09, 1999
Filed:
Oct. 14, 1997
Kou Ishizuka, Ohmiya, JP;
Yasushi Kaneda, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An optical displacement detecting apparatus is provided for detecting information on a relative displacement with respect to an object having a diffraction grating. The apparatus includes a light-emitting element for emitting a diverging light beam, a ball lens for converting the diverging light beam from the light-emitting element into a nearly collimated beam, a grating interference optical system for using the light beam from the ball lens to finally form interference light in such a form that two diffracted light beams from the diffraction grating are coupled, and a light detecting element for detecting the interference light from the grating interference optical system, wherein the relative displacement information with respect to the object is attained from a periodic signal from the light detecting element.