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:
May. 26, 1998
Filed:
Sep. 04, 1996
Mikio Sato, Utsunomiya, JP;
Hiroaki Takeishi, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A target state quantity generating unit generates a target state quantity for a stage, and a laser interferometer detects the current state quantity (position) of the stage. Based on the target state quantity and the detected state quantity (position), a compensation system constituted by a variable phase compensator and a PID compensator controls the driving operation of the stage. A memory unit stores forward and reverse gain tables, and provides adjustment information for adjusting the compensation system in correspondence with the state quantity of the stage. The corresponding gain table is selected on the basis of the driving direction of the stage, and the adjustment information is read out from the selected gain table on the basis of the position of the stage. The corner frequency of the variable phase compensator is changed on the basis of the readout adjustment information.