| 摘要 |
Automatic focusing apparatus comprising a beam focusing assembly disposed for directing through an axially spaced focal spot a scanning light beam having a periodic translational movement characterized by a first fundamental frequency component, a focus evaluating assembly disposed for detecting adjacent the focal spot a periodic translational movement of the focused beam characterized by a fundamental frequency component which is compared with said first fundamental frequency component to determine the relative phase relationship, and a target positioning assembly disposed for automatically positioning a selected surface of a target at the focal spot in accordance with the periodic translational movement of the focused beam and said determination of relative phase relationship. This automatic focusing apparatus may be embodied in a laser material removal system having a laser source connected to the focus evaluating assembly for automatic activation when the selected surface of a target is positioned at the focal spot to direct a light beam of suitably high energy onto the selected surface for removing material therefrom. |
