Patent ID: 6496093
Filing Date: 2002-12-17
Classification: G03F,H02K

Abstract:
A displacement device with a first part and a second part which are displaceable relative to one another in at least two directions, said first part comprising a carrier which extends substantially parallel to a displacement direction and on which a system of magnets is fastened in accordance with a pattern, the pattern comprising magnets of a first kind (N) with a magnetization direction perpendicular to the carrier and directed towards the second part and magnets of a second kind (Z) with a magnetization direction perpendicular to the carrier and directed away from the second part are arranged so as to alternate with one another, which system of magnets has a magnetic flux density which repeats itself in accordance with B(x)=B(x+2&tgr;), in which &tgr; is the magnetic pole pitch, the second part is provided with an electric coil system with at least one coil block unit comprising a group of k coil blocks, with k&gE;2, which coil blocks have current conductors which are situated in a magnetic field of the system of magnets, all current conductors belonging to a single coil block unit being oriented in the same direction and being fed by an n-phase system, with n&gE;2, while furthermore the magnets of the magnetic system are arranged such that, viewed in a direction perpendicular to the current conductors, the flux of the magnetic system varies substantially sinusoidally in accordance with Î¦=sin&it;Ï€&af;(x+x0)2&it;Ï„,characterized in that, for all coil blocks belonging to one coil block unit, the distance between mass centers of consecutive coil blocks, viewed in a direction perpendicular to the conductors, is substantially equal to Ï„k+pÃ—Ï„,â€ƒ&it;with&it;â€ƒ&it;â€ƒ&it;p=2,3,...â€ƒ.