| 摘要 |
PURPOSE:To promote the improvement of positioning accuracy of an XY table, by mounting one of the linear scale, which forms a position detector, and the detecting head to the side surface of a yoke and the other to a stage. CONSTITUTION:Position detectors 20', 20 in y-axis and x-axis directions, mounting respectively to their side surface a detecting head 22 and a linear scale 21, are constituted between a stage 7 and an X-axis yoke 3 and between the stage 7 and a Y-axis yoke 3. Now a threaded shaft 12 is rotated by a motor 11, and if the Y-axis yoke 3 is moved in the y-axis direction, the stage 7 moves in the y-axis direction along a guide hole 6 of the X-axis yoke 2 and stops if the position detector 20' reads its measurement value agreeing with the instruction value. Here yawing action is generated in a linear bearing 5, and if a movement theta is generated in the Y-axis yoke 3, an error e0 is generated between the y-axis direction position detector 20' and the center of the stage 7, but this value, obtaining a difference between the conventional error e1 and a measured value e2, provides a less error. In this way, the stage can be high accurately positioned. |
