Optical information recording method

Claim 1

An optical information recording method in which a digital signal subjected to pulse width modulation is overwritten on an optical disk by using one laser spot; the optical disk including a first dielectric film, a recording film, a second dielectric film and a reflecting film stacked on a substrate in this order; the recording film having composition defined by a formula Ge x Sb y Te z wherein x, y and z are atomic percentages satisfying 45≦z≦55.5, 0.5≦y/(x+y)≦0.72 and x+y+z=100; the recording film having a thickness of 10 to 35 nm; the second dielectric film having a thickness of 5 to 40 nm; the reflecting film being made of one or an alloy of at least Au, Al, Ti, Cr and Ni and having a thickness of 35 nm or more; the optical information recording method comprising the steps of: converting each of a plurality of pulses contained in the digital signal, into a pulse train composed of a plurality of pulses; and modulating a laser power between an erasing level and a recording level by the pulse train and forming a recording mark on the optical disk by the pulse train so as to record the digital signal on the optical disk; wherein the step of converting the plurality of pulses into the pulse train further comprising the step of forming the pulse train having a leading pulse and a subsequent pulse train; wherein the pulses of the subsequent pulse train have an identical width and being arranged at an identical interval; wherein the leading pulse having, at all times irrespective of length of the recording mark, a fixed width larger than the width of each of the pulses of the subsequent pulse train; wherein when the recording mark has an n-th length (n=natural number), the number of the pulses in the subsequent pulse train is (n-1).