Patent ID: 7561502

Claim:
A recording method of recording various mark and inter-mark lengths in terms of EFM-modulated information on a rewritable disc-shaped optical recording medium comprising a substrate having a wobble groove, and a phase-change recording layer, wherein a crystal state of the recording layer is an unrecorded or erased state and an amorphous state of the recording layer is a recorded state, and amorphous marks corresponding to the recorded state are formed by recording light, wherein the phase-change recording layer comprises an alloy composition containing an excessive amount of Sb as compared to a eutectic composition of SbTe, and Sb/Te ratio of the eutectic composition of SbTe is from 2.6 to 3.6, allowing recording of an EFM-modulated signal by an overwriting operation in the recording layer at up to 10-times velocity V without loss of read compatibility of the rewritable compact disc medium, wherein a modulation m 11 of a retrieving waveform of the EFM-modulated signal (eye pattern) of the recorded signal obtained as retrieved at the 1-times velocity is 60-80%, a topmost level R top of reflectivity corresponding to a maximum value I top of the eye pattern obtained as retrieved at the 1-times velocity is 15-25%, and a jitter of the individual length of amorphous marks and inter-marks obtained as retrieved at the 1-times velocity are equal to or less than 35 ns, said rewritable disc-shaped optical having a predetermined recording area by CAV (constant angular velocity) operation, in which the recording medium is rotated at a constant angular velocity, said method being carried out in the following manner: when a linear velocity within a range of from 1.2 m/s to 1.4 m/s is a reference velocity (1-times velocity), the disc-shaped optical recording medium is rotated in a way that a linear velocity at an outermost periphery of the recording area is as high as 10 times of the reference velocity, if a time length of an individual recorded mark is nT (T is a data reference clock period varying according to its radial position in a way that a product VT (V is a linear velocity in the radial position is constant, and n is an integer within a range of from 3 to 11), recording light of erasure power Pe, which is able to crystallize an amorphous-state portion, irradiates inter-mark portions, for the recorded marks, the time length (n−j)T is divided into α 1 T, β 1 T, α 2 T, β 2 T, . . . , α m T, β m T, (where m=n−1, α 1 /α i =from 0.3 to 0.7 (i is an integer within a range of from 2 to m), α i +β i−l =approximately 1 (3≦i≦m)) in this sequence so as to satisfy Σ i (α i +β i )=n−j (j is a real number within a range of 0.0≦j≦2.0), within the time length α i T (1≦i≦m), the recording light, whose record power Pw (Pw>Pe) is enough to melt said recording layer, irradiates the recording layer, and within the time length β i T (1≦i≦m), the recording light of bias power Pb (0<Pb≦0.5Pe) irradiates the recording layer, and each of α i T (i=from 2 to m) and α i +β i−1 (i=from 3 to m) is constant for any radial position.