| 摘要 |
PURPOSE:To suppress a vibration, a position shift, etc., and to secure the measuring accuracy by connecting a base and a movable object placing plate through an air bearing device, and also setting an area of an air jet surface to >=35% of the part opposed to the object placing plate and the base. CONSTITUTION:An object placing plate 7 moving in the long axis direction of a recessed groove 9 is installed to a base 1 through an air jet surface 11 for constitution roughly the whole area of the lower end face of the object placing plate 7, an air bearing device 14 consisting of an air jet hole 12, etc. provided on the air jet surface 11, a projecting line 10 of the object placing plate 7 and the recessed groove 9 of the base 1. Also, the total area of the air jet surface 11 is set to >=35% of the part opposed to the object placing plate 7 and the base 1. In this state, air of a prescribed pressure is jetted from the air jet hole 12, and the object placing plate 7 is moved by reducing a slide resistance of the object placing plate 7 against the base 1. In this way, a vibration, a position shift, an inclination, etc. of a movable member of a movable part are suppressed, and even in case when the whole device is large in size and heavy in weight, the measuring accuracy can be secured. |
