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. 10, 1998
Filed:
Sep. 03, 1996
Masanobu Hasegawa, Fujisawa, JP;
Hiroshi Osawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A position detecting system and method for detecting the relative positional relationship between first and second objects disposed opposed to each other includes providing first and second marks on first and second objects, respectively, and irradiating one of the first and second marks with light from an irradiating light source. In addition, the other of the first and second marks is placed out of an irradiation region of the irradiating source and first diffraction light diffracted by one of the first and second marks is detected. Next, a first signal corresponding to the light intensity distribution of the first diffraction light is stored in memory. Both the first and second marks are then irradiated with light from the irradiation source and second diffraction light diffracted by both the first and second marks is detected. Next, a second detection signal corresponding to the light intensity distribution of the second diffraction light is stored in memory. Finally, the relative positional relationship between the first and second objects is determined on the basis of a third signal provided by excluding the stored first signal from the stored second signal.