Patent ID: 7403456

Claim:
An optical disc recording method of recording signals so as to be overwritten by selectively irradiating a rewritable phase change optical disc with a first light beam and a second light beam, the rewritable phase change optical disc being formed so as to be adapted to recording at a first recording speed, comprising: a first step of irradiating a region to be rewritten in a phase change optical disc with a first light beam of first light intensity, thereby erasing a signal already recorded in the region to be rewritten at a second recording speed higher than the first recording speed, a degree of modulation of the signal indicative of a relative difference between a top level and a bottom level of the recorded signal being changed from a first modulation degree before the irradiation to a second modulation degree lower than the first modulation degree, and the top level being changed from the original first level to a second level lower than the original first level by irradiation with the first light beam of the first light intensity, the second level being 40% to 70% of the original first level and the second modulation degree being such that a difference between the remaining top and bottom level is about −25 dB; and a second step of selectively irradiating the region to be rewritten, the region having been irradiated with the first light beam of the first light intensity, with a second light beam of second light intensity lower than the first light intensity or a second light beam of third light intensity higher than the first light intensity, thereby recording a signal in the region to be rewritten at the second recording speed, the top level being reset from the second level to the first level by irradiation with the second light beam of the second light intensity, or the bottom level being changed to a third level lower than the second level by irradiation with the second light beam of the third light intensity.