| 摘要 |
PURPOSE:To prevent a transmision window from being contaminated by an evaporated substance, and to execute efficiently working by providing a beam guide having an uneven part on the inner surface, on the inside of a laser beam transmission window of a vacuum vessel. CONSTITUTION:A beam guide 9 which contacts a transmission window 7 side and has an uneven part on the inner surface is installed between a transmission window 7 through which a laser beam 1 transmits, and an object 3 to be worked in a vacuum working chamber 8. By an irradiation of the laser beam 1, the object 3 to be worked starts to melt, and an evaporated substance 5 is generated. This evaporated substance 5 adheres to the outer surface of the beam guide 9, but does not invade its inside diameter side. In this case, a vapor deposition preventive gas 13 is made to flow from the diagonal upper part of the beam guide 9, the evaporated substance 9 is pushed back downward and a contamination of the transmission window 7 is prevented. Also, the inside of the vacuum working chamber 8 is brought to suction by a vacuum pump, and a penetration depth of the object 3 to be worked is increased. |
