| 摘要 |
PURPOSE:To control the phase difference between two laser beams reflected by a movable part and its circumferential part by providing reflection mirrors capable of moving a part on a reflecting surface and adjusting its moving quantity. CONSTITUTION:Part of laser beams 70 in the center is taken out as a laser beam 80 on the outside through a partial reflective coating film 20 and most of the laser beams 71 in the circumferential part, are taken out as a laser beam 81 on the outside through a nonreflective coating film 5. Since both these laser beams 80, 81 are emitted through different coating films on the surface of a window mirror 4b, a phase difference occurs between them. The phase difference can be eliminated by moving the movable part 14 of a straight line motion mechanism 12 and adjusting the position of the movable reflection mirror 11. In this way, the laser beam 8 put in an equiphase is condensed by a condensing lens 15 remarkably in the center and a work piece 16 can be worked by the laser beam. |
