METHOD OF REGULATING REFLECTANCE OF WORM TYPE OPTICAL RECORDING MEDIUM AND WORM TYPE OPTICAL RECORDING MEDIUM

摘要

The reflectance of an optical recording medium for which high speed recording using a laser beam with blue wavelength or a shorter wavelength than blue light is possible is adjusted to a predetermined value of no more than 60%. ??A recording layer 18 of a high-speed write-once type optical recording medium 10 is formed by laminating first and second sub-recording layers 18A, 18B, each of which contains one type of different metal as a primary component. When laser beam of a blue wavelength is irradiated onto the recording layer 18, the irradiation causes the primary component metals contained within each of the first and second sub-recording layers 18A, 18B to diffuse and mix, and this mixing forms a recording mark with an irreversibly changed reflectance. The recording layer 18 is sandwiched between first and second dielectric layers 20, 16, and by adjusting the material and the thickness of the recording layer 18 and the first and second dielectric layers 20, 16, the reflectance of the unrecorded sections can be adjusted to a value within a range from 5% to 60%. IMAGE