| 摘要 |
PURPOSE:To improve the precision of positioning the main laser beam by detecting the incident positions of two superposed light beams by means of an optical incident position detector, and adjusting the position for superposition, thereby always accurately superposing the two light beams. CONSTITUTION:A pulse-shaped main laser beam 2 and a second light beam 4 generated in a laser device 1 are superposed and emitted to an object 7. The beams 2, 4 are partially 2', 4' reflected by a semitransparent mirror 8 and are incident upon an optical incident position detector 9. In a determination means 10, during the stopping period of the main laser beam 2', the incident position of the second light beam 4' is determined by comparing the amount of the current flowing through electrodes A-D. Then, during the period when the main laser beam 2' is outputted, the incident position of the main laser beam 2' is determined by comparing the current amount equal to the amount of the current flowing through the electrodes A-D minus the amount of the current only by the second light beam 4'. And a signal is outputted from the determination means 10 to a superposing position adjusting means 6 to adjust the position for superposing the beams 2, 4 so that the incident positions of light beams 2', 4' are in coincidence, thereby accurately superposing the two beams. |
