| 摘要 |
PURPOSE:To improve working efficiency and to uniformize the shape of a hole by arranging a beam choppering means at the opposite side of a condensing mirror as well as providing the condensing mirror and blowing an assisting gas along the optical axis of the condensing mirror. CONSTITUTION:The laser beam made incident is bent in 90 deg. direction and the parabolic mirrors 31, 32, 34 to perform a condensing are provided as well. The rotary disk 24 having a slit is arranged near the focus point position of the mirror 31 and rotated at high speed by a motor M. The beam flux condensed by the mirror 31 is made pulsing by the chopper disk 24 to form the pattern of a small aperture on the surface of a roll 1 from the through hole 26a of a nozzle 26 via mirrors 32, 33, 34. In this case an assisting gas is fed in the optical axis direction from the through hole 26a. Due to the high speed rotation of the chopper disk 24 being capable the working efficiency is improved and the hole shape is uniformized because of the flow of the assisting gas becoming in parallel to the optical axis. |
