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:
Jul. 06, 1993
Filed:
Sep. 04, 1992
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
Disclosed is a method of detecting relative positional deviation of a first object with a first grating pattern having an optical power and a second object with a second grating mark having an optical power. Light diffracted by both the first and second grating marks forms a light pattern on a predetermined plane; wherein different diffraction beams of the light diffracted by both the first and second grating marks are displaceable along the predetermined plane in accordance with the relative positional deviation of the first and second objects, in the same direction and by substantially the same quantity; and the relative positional deviation of the first and second objects is detected on the basis of the position of the light pattern on the predetermined plane.