PHASE TRANSITION TYPE OPTICAL INFORMATION RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To realize a phase transition type optical information recording medium which is capable of making recording at multiple speeds by regulating the phase transition critical relative speed of the medium and is good is the recording characteristic and repetitive recording characteristic when recording is performed at a high recording linear speed. SOLUTION: A recording device of a recording and reproducing wavelength λ=789 nm and a numerical aperture NA=0.49 is used with the phase transition type optical information recording medium in which the relative speed between the recording device and the medium in information recording is defined as vW, the recordable highest relative speed of the medium as vWH and the lowest relative speed of vWL. The medium is subjected to DC irradiation with electromagnetic waves from the recording device at the power of PE=0.75 POH with respect to the optimum recording power POH of the medium at the recording relative speed vWH when the device and the medium move at the relative speed vWH and the relative change critical relative speed v0 which is the relative speed at which the differential coefficient -dR/dv of the reflectivity R measured by the recording device attains the maximum value with respect to the relative speed v exists in a range of v0>=0.7vWH.