SYSTEM FOR SCRIBING A VISIBLE LABEL

摘要

A device is for scribing a visible label on the medium. The medium (11), for example an optical disc, has a label side provided with a radiation sensitive layer for creating the visible label via a beam of radiation. The device has a head (22) for providing the beam and generating a detector signal in dependence of radiation reflected from the medium, and a focus unit (32) for generating a focus control signal for focusing the beam. A label control unit (33) controls the scribing in dependence of label data. The focus unit (32) detects a focus error by including a focus excitation signal in the focus control signal and detecting a deviation in the detector signal in dependence of the focus excitation signal. The label control unit (33) is for controlling the focus unit in dependence on the label data to detect the focus error during said scribing and without interrupting said scribing.