| 摘要 |
PURPOSE:To shift a stage freely at high precision by a method wherein spiral racks are provided on both surfaces of the stage, and the stage is pinched in two lead screws engaging with the racks for shifting by turning the lead screws on the plane travelling stage. CONSTITUTION:Both ends of two lead screws 4, 5 are supported rotatably with bearings on a set of supporting plates 2, 3 on a base plate 1, and reversible motors 6, 7 are mounted on each of them so that they are rotatable independently. A travelling stage 8 is arranged between the two lead screws 4, 5, and a pin 13 sliding on the base plate 1 is provided on its lower surface. A spiral rack 11 on the upper surface 9 of the stage 8 is engaged with the lead screw 4 and a spiral rack 12 on the lower surface 10 is engaged with the lead screw 5. From rotating the lead screws 4, 5, the stage 8 can be shifted in any desired direction at high precision and also at high speed accordingly. |
