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:
Feb. 27, 1996
Filed:
May. 16, 1995
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method of detecting the positional relationship between a first object and a second object is disclosed which includes projecting a first light through a convex lens mark of the first object and a concave lens pattern of the second object onto a first plane and projecting a second light through a concave lens mark of the first object and a convex lens pattern of the second object onto the first plane, wherein a first spacing between positions of incidence of the first light and the second light on the first plane increases with displacement of the second object relative to the first object in a predetermined direction. The method also includes projecting a third light through a concave lens mark of the first object and a convex lens pattern of the second object onto a second plane and projecting a fourth light through a convex lens mark of the first object and a concave lens pattern of the second object onto the second plane, wherein a second spacing between positions of incidence of the third light and the fourth light on the second plane decreases with displacement of the second object relative to the first object in the predetermined direction. The method also includes determining a reference for the detection of a position of the first object relative to a position of the second object on the basis of the first spacing and the second spacing as they become substantially equal to each other.