Method and apparatus for determining focus position of a laser

摘要

A method and apparatus (100) for positioning a surface (112) of a workpiece (110) for laser machining. A laser beam (104) is focused to a focal point to form a plasma (130) generating a plasma emission. An imaging system (114,116) is oriented to receive the plasma emission and generate a plasma image. The imaging system is adjusted to focus the plasma image and is then fixed. The laser is then diverted away from the focal point and an illumination source (122) is activated to illuminate the surface (112) of the workpiece (110). The imaging system generates an image of the surface (112) of the workpiece (110). The workpiece is adjusted in position toward the focal point until the image of the surface of the workpiece is in focus. <IMAGE>