| 摘要 |
PURPOSE:To realize long life of a mirror and stabilization of processing quality for a long period of time by providing openings to the whole periphery of reflecting surface of mirror for allowing the laser medium gas to be ejected therefrom. CONSTITUTION:An opening 9 is provided at the whole periphery of the reflecting surface of a mirror 1 to allow the laser medium gas to be ejected. The gas entering a circular space chamber 16 from a gas guiding hole 9 is then guided to a joint pipe 11 from the opening a of mirror 1 while is it ejected to the reflecting surface of mirror 1 uniformly from the whole periphery. Therefore, contaminant substances increasing with time within the gas, for instance, an oxide of electrode material and oil do not easily reach the surface of mirror 1 and if these area adhered, these can be blown out by the gas. Accordingly, amount of contaminants burned and adhered to the mirror 1 can be reduced and operation life of mirror can be elongated and processing quality can be stabilized for a long period of time. |
