| 摘要 |
At its exit end, an articulated optical system contains a triple mirror which reflects part of the laser beam into itself and back to a detector disposed in the vicinity of the entry of the articulated optical system. The detector signal is delivered to an adjusting mirror also disposed at the entry of the articulated optical system. The adjusting mirror compensates for drifting of the laser beam caused by errors in the telescopic guides and bearings of the articulated arm. Since the laser beam, after reflection at the triple mirror, is returned once again by means of all the movable elements of the articulated arm, the directional association between the displacement measured by the detector and the follow-up adjusting movement of the adjusting mirror remains independent of the amount of rotation in the joints. |
