US Patent 7557469 Positioning system and linear motor

A positioning system includes a stage configured to move while carrying an object thereon, an interferometer configured to measure a position of the stage, a driving unit configured to drive the stage, a heater provided between a light path of the interferometer and a coil which is a component element of the driving unit, and a cooling jacket configured to cover the coil and to circulate a cooling medium therein. The heater is provided on a surface of the cooling jacket.