Patent ID: 6879063

Claim:
A displacement device comprising a first part and a second part, at least one of which can be displaced with respect to the other in at least an X-direction and a Y-direction perpendicular thereto, the part comprising an array of magnets arranged in accordance with a pattern of rows extending parallel to the X-direction and columns extending parallel to the Y-direction, the array of magnets comprising: magnets of a first type, having a magnetization direction which extends at right angles to the X- and Y-directions and towards the second part, and magnets of a second type, having a magnetization direction which extends at right angles to the X- and Y-directions and away from the second part, said magnets of a first type and magnets of a second type being alternatively arranged in each row and each column, each of said magnets of the first and second types corresponding to one of the rows and one of the columns, and magnets of a third type arranged between each pair of juxtaposed magnets of the first and the second type in each row and column, each magnet of a third type having a magnetization direction which extends in one of the X- and Y-directions, wherein each of said magnets of the first and second types has a rectangular cross-section in a first plane extending in the X- and Y-directions, and wherein each of said magnets of the third type has a cross-section in the first plane that is different from the cross-section of said magnets of the first and second types.