During production of the sampling inspection method of phase-change optical information recording medium

摘要

PURPOSE:To shorten inspection time by repeatedly irradiating a recording layer with a laser light beam required for making the recording layer into an amor phous material with direct current. CONSTITUTION:When the recording layer is irradiated with the laser beam of DC power, the recording layer is uniformly made into the amorphous material and a reflection rate is deteriorated compared to an initial crystallization state. A C/N ratio, an erasure ratio, jitter and an error rate can be evaluated after overwriting with a specified frequency in such a state. The noise level and the drop-in defect of a reproduction signal can be detected even if overwriting is not executed and deterioration can quantitatively be evaluated. When a cycle test is conducted with a regular single frequency, the drop-in defect is found to increase, for 104-times even in a medium where the error rate becomes increasing after 105-times and the time of the cycle test can considerably be shortened.