Patent ID: 8008815

Claim:
A planar stage moving apparatus for a machine comprising: first to fourth linear motors for applying, between a base and a table, a movement force to the table, each linear motor including a stator core on which a coil is wound and which is fixed to the base and a mover core to which permanent magnets are attached and which is fixed to the table; an air bearing unit to provide a repulsive force between the base and the table, to separate the base and the table and thereby permit to move under the influence of magnet fields when currents are applied to the coils of the linear motors, wherein the air bearing unit comprises a plurality of air bearing pads for each of said linear motors, wherein the air bearing pads are provided between the permanent magnets of each of said linear motors; and a linear encoder installed on one side of the table to measure movement of the table, the first and third linear motors being provided between the base and the table on the lower and upper sides of the table respectively to move the table in the X-axis directional movement of the table, the second and fourth linear motors being provided between the base and the table on the right and left sides of the table respectively to move the table in the Y-axis directional movement of the table, the air pads being fixed to a plurality of grooves formed on the lower surface of the table respectively and a plurality of air supply lines formed at intermediate portions of the table to provide a pneumatic pressure to the grooves respectively.