Motion guiding device

Claim 1

A motion guiding device, comprising: a base having a reference surface; a guide fixed to said base and having a first guiding surface extending in a first direction; a first stage having a first gas bearing disposed opposite to said reference surface of said base and a plurality of second gas bearings disposed opposite to said first guiding surface of said guide, wherein said guide is disposed at only one side of said first stage, wherein the motion of said first stage in the first direction is guided by said first guiding surface of said guide and said reference surface of said base and wherein said first stage has a second guiding surface extending in a second direction different from the first direction; a second stage disposed so as to straddle said first stage, said second stage having a third gas bearing disposed opposite to said reference surface of said base and a fourth gas bearing disposed opposite to said second guiding surface, wherein motion of said second stage in the second direction is guided by said second guiding surface of said first stage and said reference surface of said base; a first driving actuator actable on said first stage to move said first stage in the first direction, wherein said second stage moves in the first direction with said first stage through said fourth gas bearing; a second driving actuator actable on said second stage to move said second stage in the second direction; and a magnet unit provided on said first stage and disposed opposite to said first guiding surface, for urging said first stage toward said guide, wherein said magnet unit is disposed between said second gas bearings with respect to the first direction.