US 5,196,745 A · Magnetic positioning device

Abstract

A device for controlling the relative position between a movable platen and a stator, with linear motions, for example in the 200 to 300 mm range, being provided in one or two of the degrees of freedom and precision control in the 10 nm range being provided in six degrees of freedom. Linear motion is provided by adjacent pairs of magnetic arrays and coil arrays, with the magnetic array of each pair preferably being mounted to the platen and the coil array to the stator. Both arrays have smooth mating surfaces spaced by a predetermined gap. Adjacent magnets of each magnetic array are oppositely poled and each coil array has multiple phases, the pitches of the two adjacent arrays preferably being substantially equal. The weight of the platen may be supported by the magnetic and coil arrays or separate magnets may be provided for this purpose.

Claims42

Dependent claims

A device for positioning a movable member having a first surface relative to a stationary member having a second surface, said first and second surfaces being adjacent each other, the device comprising:

a magnetic array mounted in one of said surfaces, said array having adjacent magnetic elements in the direction of movement which are adapted to be of opposite polarity;
a multiphase coil array mounted in the other of said surfaces, said other surface being formed of a material having low magnetic permeability;
said magnetic array and coil array being mounted so as to provide smooth, mating adjacent surfaces spaced from each other by a substantially uniform gap;
and
means for selectively applying controlled currents to each phase of said coil array in a phase, amplitude and polarity to interact with said magnetic array to drive said movable member to a selected position relative to aid stationary member.

2 more elements

A device for positioning in at least two degrees of freedom a movable member having a top and bottom surface relative to a stationary member having corresponding surfaces adjacent to at least one of said top and bottom surfaces, the device comprising:

at least one magnetic array mounted in one of said member surfaces for each of said degrees of freedom, each of said arrays having adjacent magnetic elements in the direction of the degree of freedom which elements are of opposite polarity;
a multiphase coil array for each magnetic array mounted in the surface adjacent said one surface of the other member;
each magnetic array/coil array pair being mounted so as to provide smooth, mating adjacent surfaces spaced from each other by a substantially uniform gap;
and
means for applying controlled currents for each phase of each of said coil arrays in a phase, amplitude and polarity to interact with the corresponding magnetic array to drive the movable member in said at least two degrees of freedom to a selected position relative to said stationary member.

2 more elements

Dependencies are inferred from the claim text.

Magnetic positioning device

Life of this patent

Magnetic positioning device

Life of this patent

Abstract

Claims42