Workpiece processing apparatus using laser beam, has free jet of window gas which passes through cavity to produce negative pressure in region of workpiece

摘要

The apparatus includes a laser, a focussing lens system, and a device for producing a negative pressure in the surroundings of the focussed spot. The device for producing the negative pressure includes an aerodynamic window (20) which can be placed tightly against the workpiece (10), and a cavity (28) extending in a direction at right angles to the propagation direction of the laser beam. A free jet of a window gas passes through the cavity to produce a negative pressure in the section of the cavity near to the workpiece.