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:
Apr. 10, 2001
Filed:
Apr. 27, 1999
Shinji Wakui, Utsunomiya, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An anti-vibration table having a structure supporting a movable stage is supported by an air spring actuator. The control system of the air spring actuator has a position feedback system for positioning the anti-vibration table at a predetermined equilibrium position on the basis of the position detection signal of the anti-vibration table, an acceleration feedback system for imparting damping characteristics to the anti-vibration table on the basis of the acceleration detection signal of the anti-vibration table, and an applied pressure feedback system for controlling the applied pressure of the air spring actuator. A correction signal for correcting a tilt of the anti-vibration table, which is generated when the stage on the anti-vibration table moves, is generated on the basis of a signal from a laser interferometer for detecting the position of the stage, and feedforward-input to the applied pressure feedback system.