| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable long distance transmission of a large output laser beam that remains stable for a long time by controlling temperature distribution inside a mirror in the transmission system of a laser welding equipment and thereby preventing diffusion of the laser beam. SOLUTION: The neighborhood of the rear surface of the mirror is heated so that a reverse camber takes place that may balance or exceed a camber due to the temperature rise on the mirror surface, with the temperature distribution controlled on the side cross section of the mirror. For this purpose, while the mirror 1 surface (reflecting surface) is cooled with a cooling passage 2 provided, the mirror 1 rear surface is heated to about 30-40 deg.C by a heater 4 provided discretely on the rear side or by a hot water passage 5 provided just beneath the rear surface of the mirror 1 where hot water of about 30-40 deg.C is made to flow. Otherwise, a cooling gas such as air or an inactive gas is injected from a nozzle 3 to the center surface of the mirror 1, cooling the center surface and making its temperature lower than that of the rear surface. As a result, diffusion of a laser beam can be prevented in the mirror in a high output laser transmission system.</p> |
