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. 10, 1998
Filed:
Jan. 30, 1997
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A detecting system for detecting a surface position of an object, includes a light source, a first grating having a light collecting function, wherein the first grating is illuminated with light from the light source, a second grating having a light collecting function, a first optical system for imaging the first grating onto the object in a direction oblique to the surface of the object, a second optical system for re-imaging the image of the first grating, on the surface of the object, onto the second grating, wherein a moire fringe is produced by the second grating and the re-imaged image of the first grating, and a photodetector for detecting a position of a converged point of convergent light as produced by the moire fringe, wherein the surface position information of the object is determined on the basis of information related to the converged point position as detected by the photodetector.