Patent ID: 7091636

Claim:
A position-control stage system; comprising a bed, a turntable supported for rotation on the bed through a bearing, and a motor driving the turntable relative to the bed in a circular direction, the motor including a primary side having an armature assembly and a secondary side having a field magnet; wherein the armature assembly is composed of armature windings made of coreless annular coils wound in a form of a flat configuration; wherein the field magnet is composed of magnet segments made in a flat configuration, which are juxtaposed underneath the turntable in opposition to the armature windings in an array that alternates in polarity circularly in a circumferential direction; wherein the bearing is fastened to the bed by a first retainer member secured to the bed; wherein the armature windings are juxtaposed in a circumferential direction on a circular surface of the first retainer member in opposition to the field magnets; wherein the first retainer member fits into the turntable which is allowed to turn relative to the first retainer member through the bearing so that the circular surface of the first retainer member lies in the circular recess defined between a journal portion extended at a center of the turntable and a circular flange raised around an outside periphery of the turntable; and wherein the armature windings are each made extended across an overall radial length of the circular surface of the first retainer member.