| 摘要 |
PURPOSE:To execute a measurement with high accuracy even in case of a large- sized device, and to reduce the accuracy drop in the X direction by forming a lng part so that it is scarcely inclined and also scarcely displaced in the direction (X direction) for connecting both leg parts, with regard to an air bearing device provided on a lower end supporting part of one leg part. CONSTITUTION:A guide member 41 whose section is a square is formed by an upper end horizontal guide surface 41A and both sides vertical guide surfaces 41B having an angle relation of a right angle each other. Also, this machine has an air jet surface 43A and 43B opposed to each guide surface 41A and 41B, respectively, and it is provided with a lower end supporting part 43 guided by the guide member 41. Accordingly, one leg part 6 provided vertically on the lower end supporting part 43 is supported so that it is scarcely inclined and also scarcely displaced in the X direction. In this way, the accuracy drop in the X direction is reduced, and especially, even in case when the whole device is large in size and heavy in weight, a measurement is executed with high accuracy, and also the surface of an object placing plate can be used widely. |
