| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it possible to irradiate an object with a beam of light with high positional accuracy even if a stage is displaced in the Y-axis direction due to vibrations, etc. SOLUTION: A Y-position detector 2 measures the distance up to a stage 1 and detects the position of the stage in the Y-axis direction. A stage position setting circuit 4 outputs a signal representing the distance between the Y-position detector 2 and the stage 1 when stage 1 is not displaced according to the data supplied by a CPU 3. A compactor 5 calculates the difference between this signal and the signal representing the distance between the stage and the Y- position detector outputted by the stage position setting circuit 4 and outputs the result to a gain adjusting circuit 10. The gain adjusting circuit 10 adjusts the output signal level of the comparator 5, and supplies the signal to an adder 7. The adder 7 adds the output signal of the gain adjusting circuit 10 to an electric signal from a scanner position setting circuit 6, thereby corrects the electric signal from the scanner position setting circuit 6 and supplies the signal to a scanner driving circuit 8.</p> |
