Linear motor magnetic shield apparatus for lithographic systems
US9136751B2 · kind B2 · utility
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10References
24Claims
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Key dates
| Filing date | Sep 14, 2012 |
| Grant date | Sep 15, 2015 |
| Priority date | — |
| Expiry date | Oct 6, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K2201/18
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A magnetic shield having non-magnetic gaps provides reduced magnetic cross-talk for a linear motor array in a precision positioning system. Redirecting the leakage flux limits the cross-talk and associated deleterious effects. Such preferred magnetic circuit paths for the leakage are affixed to the moving magnet system of the linear motor. Embodiments of the preferred flux leakage paths are realized by providing a ferromagnetic shield separated by a non-magnetic gap between the permanent magnets and the back-irons. In another embodiment, the ferromagnetic shield separation includes diamagnetic materials.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.