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:
Dec. 28, 1999
Filed:
Dec. 02, 1997
Hirohito Ito, Funabashi, JP;
Kotaro Akutsu, Soka, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A precision stage is provided so as to be movable along the Z axis, in the .theta. direction, which is the direction of rotation about the Z axis, and in two oblique directions inclined with respect to the Z axis. The stage has a sensor for measuring stage position along the Z axis. Reference-position return of this sensor is carried out. Reference-position return of two Y laser interferometers for measuring the .theta. position of the precision stage is carried out in a state in which the positions of the precision stage in the direction along the Z axis and in the oblique directions are held at predetermined reference positions. After this reference-position return is carried out, reference-position return is performed with regard to an X laser interferometer and the two Y laser interferometers in a state in which the positions of the precision stage in the direction along the Z axis, in the oblique directions and in the .theta. direction are held at predetermined reference positions.