| 摘要 |
<p>A method for focusing the objective of an optical pick-up head on the desired information layer of an optical memory device. The focus error signal (29) when the focus servo loop gate (32) is in open loop mode is used to determine the location of the information layers or layer, and to provide a mechanism for providing a signal (loop closing signal) which can be used to time/trigger the closing of the focus servo loop gate (32) by the servo controller (35), thus providing focus on the desired layer. One example of an embodiment of the invention is an application to a dual layer optical disc.</p> |
