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. 12, 1996
Filed:
Dec. 02, 1994
Noriyasu Hasegawa, Utsunomiya, JP;
Tetsuzo Mori, Atsugi, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A method and apparatus for measuring relative positional deviation between first and second diffraction gratings formed on an object is disclosed, wherein, in detection of a signal corresponding to the relative positional deviation between the first and second diffraction gratings, a suitable delay is determined in accordance with a signal corresponding to a relative positional deviation between third and fourth diffraction gratings formed on the object and having a predetected relative positional deviation, and wherein the measurement of the positional deviation between the first and second diffraction grating is done on the basis of a signal corresponding to that deviation and of the delay thus determined.