LASER BEAM MACHINING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a laser beam machining device which efficiently drills a hole having a high aspect ratio. SOLUTION: A variable focal distance means which is composed of a lens 3 and a bens moving means 13 is arranged between an aperture 2 and an fθlens 7. When the lens 3 is moved, the position of the aperture 2 looked from the fθlens 7 varies and the position of an image formation plane 12 of the aperture 2 varies in the direction of the optical axis. Thus, the intensity distribution of a laser beam on the surface of a work 8 is kept constant by moving the lens 3 in time with the proceeding of the machining.