Patent ID: 7420298

Claim:
A high precision z-theta stage having a horizontal translation axis (z-axis) and a rotary axis (theta-axis) parallel with the translation axis comprising: a base plate having upper surfaces lying in a plane; parallel spaced apart linear translation stages each having parallel linear bearings with bearing surfaces mounted at a substantially equal distance from the planar surfaces of the base plate, each linear translation stage having a brushless linear motor; a carriage supported between the parallel translation stages by the linear bearings; and a rotation stage carried by the carriage between the parallel translation stages, said rotation stage comprising a brushless rotary motor having a shaft journaled with an axis parallel to the linear bearings, the carriage and rotation stage having a vertical and a horizontal center of gravity, each brushless linear motor being connected to the carriage to apply translation forces in a horizontal plane intersecting said vertical center of gravity, said brushless rotary motor comprising a permanent magnet rotor and a surrounding armature casing supporting an armature winding on the inner diameter thereof, said armature casing having a cooling fluid labyrinth formed in the casing with an inlet and outlet port in communication through the labyrinth.