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:
Jun. 01, 2004
Filed:
Jul. 11, 2000
Steven P. Cahill, Newton, MA (US);
Bradley L. Hunter, Lexington, MA (US);
GSI Lumonics Corp., Billerica, MA (US);
Abstract
A high-speed precision positioning apparatus has a stage supported by a platen. The stage is driven by a plurality of drive motors that are co-planar with the stage and arranged symmetrically around the stage. The drive motors apply drive forces directly to the stage without any mechanical contact to the stage. The drive forces impart planar motion to the stage in at least three degrees of freedom of motion. In the remaining three degrees of freedom the motion is constrained by a plurality of fluid bearings that operate between the stage and the platen. The drive motors are configured as magnets, attached to the stage, moving in a gap formed in-between top and bottom stationary coils. Integral force cancellation is implemented by a force cancellation system that applies cancellation forces to the stage. The cancellation forces, which are co-planar with a center of gravity of the stage and any components that move with the stage, cancel forces generated by planar motion of the stage. Interferometric encoders are used as position detectors.