Bearing device, magnetic gravity compensator, vibration isolation system, lithographic apparatus, and method to control a gravity compensator having a negative stiffness

Abstract

The invention relates to a bearing device arranged to support in a vertical direction a first part of an apparatus with respect to a second part of the apparatus, comprising a magnetic gravity compensator. The magnetic gravity compensator comprises: a first permanent magnet assembly mounted to one of the first part and the second part and comprising at least a first column of permanent magnets, the first column extending in the vertical direction, wherein the permanent magnets have a polarization direction in a first horizontal direction or in a second horizontal direction opposite to the first horizontal direction, wherein vertically adjacent permanent magnets have opposite polarization directions, a second permanent magnet assembly mounted to the other of the first part and the second part and comprising at least one other column of permanent magnets, the at least one other column extending in the vertical direction, wherein vertically adjacent permanent magnets of the at least one other column have opposite polarization directions in the first horizontal direction or the second horizontal direction, wherein the first permanent magnet assembly at least partially encloses the second permanent magnet assembly.