| 摘要 |
<p>PROBLEM TO BE SOLVED: To miniaturize a lens condensing optical system furnished on an output head for laser beam welding of a thin plate, to reduce the weight of the optical system, to simplify the structure and to realize the system at a low cost. SOLUTION: A YAG laser beam 16 emitted from a laser beam source is led to the lens condensing optical system 8 via an optical fiber 4, a thin stainless steel plate 5 is irradiated with the laser beam and a laser beam welding is performed. The lens condensing optical system 8 is composed of a front group lens 21 for collimator and a rear group lens for condensing 22, and each group of lens is composed of a single planoconvex lens. The longitudinal aberrationΔs of the lens condensing optical system 8 is 5 to 15 mm, the condensing ratio is 0.75 to 1.25, the aperture number NA is selected to be 0.1 to 0.2. It is also possible that the optical fiber 4 is eliminated and the laser beam generated by the laser beam source 3 is directly guided to the lens condensing optical system 8.</p> |
