| 摘要 |
<p>The invention relates to an optical disk apparatus for reading and/or writing information from/on an optical disk (1). The apparatus comprises an auxiliary lens (17) to compensate for optical aberrations and a servo loop for positioning said auxiliary lens relative to a main lens (15). The servo loop comprises an actuator (50) for driving the auxiliary lens (17) and a control means conceived to feed the actuator coil (55a) with a drive current (Id) dependent on a position signal which is derived from the actual inductance of the actuator coil and a reference signal (Vr) which is indicative of a desired position of the scan element. The apparatus comprises an inductance influencing means (54) to vary the inductance of the actuator coil (55a) as a function of the position (p) of the scan element (17).</p> |
