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AssigneeU.S. Philips Corporation
InventorsPetrus C.M. Frissen, Johan C. Compter, Antonius T.A. Peijnenburg, Erik R. Loopstra
Estimating the term…
A positioning device comprising a first part (1) which is movable relatively to a second part (2) in an X-direction and a Y-direction, said first part (1) comprising a carrier (5) on which a system of magnets (3) is arranged according to a pattern of rows (7) and columns (8) extending parallel to the X-direction and the Y-direction, respectively. The magnets in each row and column are arranged according to a Halbach array, i.e. the magnetic orientation of successive magnets in each row (7) and each column (8) rotates 90° counterclockwise. The second part (2) comprises an electric coil system (4) with two types of electric coils (C1, C2), one type having an angular offset of +45°, and the other type having an offset of −45° with respect to the X-direction. The magnet configuration causes a very strong magnetic field.
A displacement device comprising a first part (1) and a second part (2) which can be displaced with respect to each other in at least an X-direction and a Y-direction perpendicularly thereto, the first part comprising a carrier (5) which extends substantially parallel to the X-direction and the Y-direction and on which a system (3) of magnets is secured in accordance with a pattern of rows (7) extending parallel to the X-direction, and columns (8) extending parallel to the Y-direction, an equal distance being present between the rows and between the columns, and magnets of a first type (N), having a magnetization direction which extends at right angles to the carrier (5) and towards the second part (2), and magnets of a second type (Z), having a magnetization direction which extends at right angles to the carrier (5) and away from the second part (2), being alternately arranged in each row (7) and in each column (8), and a magnet of a third type (H) being arranged in each column (8) between each pair of juxtaposed magnets of the first (N) and the second type (Z), which magnet of a third type has a magnetization direction which extends parallel to the Y-direction and towards the magnet of the first type (N), while the second part (2) is provided with an electric coil system (4) comprising at least one electric coil of a first type (C1) which has current conductors (9) which are situated in a magnetic field of the system of magnets and which include an angle of substantially 45° with the X-direction, and comprising at least one electric coil of a second type (C2), which has current conductors (10) which are also situated in the magnetic field of the system of magnets and which include an angle of substantially 45° with the X-direction, and said current conductors extending perpendicularly to the current conductors (9) of the first electric coil (C1), characterized in that in each row (7) of magnets of the first part (1), also a magnet of the third type (H) is arranged between each pair of juxtaposed magnets of the first (N) and the second type (Z), which magnet of the third type has a magnetization direction extending parallel to the X-direction and towards the magnet of the first type (N).
A displacement device as claimed in any one of the preceding claims, characterized in that the length (19) of the current conductors (9, 10) of the coils, which current conductors are situated in the effective magnetic field, is approximately equal to k times the pole pitch (16) of the magnets, with k being 2, 4, 6, . . . , and the pole pitch (16) of the magnets being defined as the distance between two adjacent diagonal lines on which center points (17) and (18), respectively, of magnets of the same type (N) and (Z) are situated.
Dependencies are inferred from the claim text.