Patent ID: 7408852
Filing Date: 2008-08-05
Classification: G11B,Y10T

Abstract:
1. A 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 12-times velocity V without loss of read compatibility of the rewritable compact disc medium, wherein a modulation m a topmost level R 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 optical recording medium 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 within the time length α each of α