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. 15, 2004
Filed:
Feb. 14, 2003
Applicant:
Inventors:
Assignee:
Kabushiki Kaisha Yaskawa Denki, Fukuoka, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H02K 4/100 ;
U.S. Cl.
CPC ...
H02K 4/100 ;
Abstract
Stage apparatus are disclosed that provide high-accuracy positioning and movements of a stage platform, while generating reduced stray magnetic-field fluctuations and perturbations. The stage apparatus include at least one linear motor having a stator and a moving coil. Each stator includes a yoke that includes linear arrays of permanent magnets relative to which the moving coil, attached to the stage platform, moves inside a linearly extended coil gap in the yoke. A magnetic-shield plate extends around all outer surfaces and edges of the yoke as well adjacent the coil gap. The magnetic-shield plate is made of a magnetic material having high magnetic permeability.