Electric motors and positioning devices having moving magnet arrays and six degrees of freedom

摘要

A two-dimensional electric motor having a moving magnet and positionable in six degrees of freedom. The electric motor has a coil array and a magnet array. The magnet array has a smaller width than the coil array in the moving magnet embodiment. The invention's process of achieving motion of a coil array with respect to a magnet array in six degrees of freedom includes providing an electrical current distribution to a coils. The motion is controlled in a first direction and a vertical direction between a portion of the coils and a portion of the magnet array. The electrical current distribution has two wavelike components having a same period but approximately ninety degrees out of phase. The invention's positioning devices do not require air bearings. Instead, the suspension of the support member by magnetic attraction to the frame or by interaction of the coil array and the magnet array replace the air bearings. The invention's electric motors and positioning devices should be useful in positioning wafers during semiconductor manufacture.