| 摘要 |
PURPOSE:To finely position a table with high accuracy, by reducing the scale of the movement of ball screws driven by pulse motors, through levers to drive the table. CONSTITUTION:An X-table 2 is provided on a fixed table 1 so that the X table 2 can be moved in a direction X. A Y-table 3 is provided on the X-table 2 so that the Y-table 3 can be moved alone in a direction Y. A theta-table 4 is provided on the Y- table 3 so that the theta-table 4 can be rotated alone and extends through the tables 1, 2, 3. A Z-table 5 is provided on the theta-table 4 so that the Z-table 5 can be moved up and down. To drive these tables 2-5 respectively, pulse motors 2-9 are installed. The turning forces of the pulse motors 6-9 are converted into straight motion by ball screws 10-13 to move the tables 2-5 through levers 14-17. Minimum quantities of movement necessary for shafts are selected by optionally determining the factors of the motors 6-9 and the ball screws 10-13 and the ratios of the levers 14-17 as to their fulcra. Fine positioning is thus effected so that errors are minute. |
