Process and device for positioning and controlling a high energy source, in particular a laser relative to a workpiece

The invention relates to a process and a device for positioning and controlling a high-power energy source, in particular a laser, relative to a workpiece. In this case, the laser beam is positioned by means of an optical system and the surround field of the impingement site of the laser beam on the workpiece is observed during laser operation, whereupon the laser beam is controlled in accordance with the result of the observation. In order simply and exactly to configure the positioning and control of the laser beam, the direction of observation is selected according to the invention to be different to the direction of the laser beam, and in addition the impingement site of the laser beam on the workpiece itself is observed during laser operation. No additional illumination is required apart from the working laser. By optical filtering, there is generated in the observing plane an image of the impingement site relative to its surround field, from the contrast of which the information on positioning and controlling the laser is determined.