| 摘要 |
PURPOSE:To suppress the deterioration of a machining lens and to make it possible to improve stability and reliability, by arranging a wavelength selecting mirror between the machining lens and a material to be machined, and attenuating ultraviolet rays from the material to be machined. CONSTITUTION:A laser beam 2, which is oscillated in a laser oscillator 1, is reflected by total reflection mirrors 3a and 3b. The beam passes through a machining lens 4 and is converged on a material to be machined 5 through a wavelength selecting mirror 6. At this time, the mirror 6 has a high reflectivity with respect to the beam 2 having a wavelength of 10.6mum. Therefore, the characteristics of the beam 2 are not deteriorated. Meanwhile, ultraviolet rays having a wavelength of 0.5mum or less from the part to be welded on the material to be machined 5 is absorbed by the mirror 6 and does not reach the lens 4. Thus, the deterioration of the lens 4 can be suppressed, and stability and reliability can be improved. |
