| 摘要 |
<p>The machine may be automatically adjusted so that the machining point corresponds with the point of concentration of the beam. The laser beam for machining and the control beam are both concentrated by lenses. The control beam is transmitted by a pair of semi-transparent mirrors so that a portion of it falls onto the article. If the article is located at the foucs of the lens transmitting the machining beam, then the two concentration points coincide. The control beam is reflected back and is detected by a sensor after its frequency has been modulated by a vibrating plate. The electric signal is then rectified and its value gives an indication of the gap between the article and the lens focus. The signal may be passed to a servo-motor which automatically adjusts the position of the machining head.</p> |
