Information storage system and device for improved erasing of information written on a record carrier

摘要

Information storage system, device and record carrier for improved erasing of information written on the record carrier. A radiation beam is focused on a recording layer of the record carrier containing phase-change material. Crystalline information areas are written on initially amorphous portions of the recording layer by means of the radiation beam having its intensity modulated in accordance with write pulses. The information areas are erased by means of the radiation beam having its intensity modulated in accordance with erase pulses. The time duration of each of the erase pulses (and, therefore, the intensity of the radiation beam being modulated in accordance therewith to heat the recording layer) and the cooling time of the recording layer thereafter is short enough that areas of the recording layer which are heated during erasing to a temperature above the crystallization temperature of the recording layer but lower than the melting point of the recording layer remain above the crystallization temperature for a period of time which is shorter than the crystallization time for the recording layer. The recording layer may contain a track and have more crystallization nuclei proximate to a centerline of the track than away from the centerline.