| 摘要 |
A device for scanning an optical record carrier, which has a data layer with parallel tracks, has an optical head (22) comprising a radiation source for generating a radiation spot on a track. A control unit (36) coupled to an actuator controls, in response to a difference of an error signal (55,56) and a target value, a parameter of the optical head, for example focus. A power correction unit (31) adds a correction amount (59) of power to the power (58) of the radiation source. The correction amount is dependent on a deviation of the error signal from the target value. The correction power advantageously compensates the deteriorating effect of the radiation spot parameter being off target, e.g. defocus, in particular in a period (60) after a defect. |
