| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a beam collimation device of a laser beam machine capable of high-speed, stable and excellent cutting of a thin plate and also capable of steady cutting a thick plate, in a wide machining area from the near to the far positions, and to provide a laser machining method using such a device. SOLUTION: In a laser beam machine 21 provided with a variable optical path length, the atmospheric side of the output mirror 5 in a laser generator 3 is formed with a concave lens. A first and a second convex lenses 25, 29 which are freely movable back and forth are provided at a certain interval on the optical axis 27 of the concave lens of this output mirror 5. And a beam collimation device 23 is formed which functions as an reverse-Galileian beam expander by the concave lens together with the first convex lens 25 or the second 29.</p> |
