| 摘要 |
PURPOSE:To effect a positioning of ultra high accuracy, by disposing magnetic bodies on opposite sides of XY movable guides and exciting coils for producing magnetic fields on a stage for balancing repelling forces at a prescribed position each other so that the stage is restricted at a predetermined position. CONSTITUTION:XY movable guide 2, 3 have magnetic bodies 51a, 51b disposed on their opposite sides and a stage 4 has exciting coils 52a, 52b for producing magnetic fields which confront the magnetic body 51a, 51b, respectively. When the guides 2, 3 are restrained and electric current is supplied to the respective coils 52a, 52b to produce magnetic fields for positioning the stage 4, the magnetic bodies 51a, 51a, and 51b, 51b on the opposite sides of the guides 2, 3 which correspond to the respective coils 52a, 52b effect magnetic attraction or repelling each other. As a result, the repelling force of the attracting force which is balanced at the opposite sides of the guide 2, 3 acts as a restricting force for keeping the stage 4 at a predetermined position with respect to the guides 2, 3 so that the air floating stage 4 becomes stationary perfectly. |
