Patent ID: 7961581

Claim:
A data recording method for recording data as edge position information, including marks and spaces of multiple different lengths, on a storage medium by irradiating the storage medium with a pulsed energy beam, the method comprising: (A) generating an NRZI data based on the data to be recorded; (B) determining a write pulse waveform, defining the power modulation of the energy beam, according to the code lengths x of respective codes included in the NRZI data, the code lengths x (where x is an integer equal to or greater than one) corresponding to mark lengths of xTw (where Tw is a detection window width); and (C) modulating the power of the energy beam based on the write pulse waveform, wherein if the shortest code length of the NRZI data is n (where n is an integer equal to or greater than one), the step (B) includes assigning a write pulse waveform that has only one write pulse Pw, followed by a cooling pulse, to recording mark making periods corresponding to codes with code lengths x of n, and n+1, and a write pulse waveform that has multiple write pulses Pw, followed by a cooling pulse, to recording mark making periods corresponding to codes with code lengths x of n+2 or more, respectively, wherein the write pulse waveform in the recording mark making period corresponding to codes with code lengths x of n+2 or more includes write pulses, of which the number is equal to the quotient obtained by dividing x by two, and wherein the start position of a first pulse among the write pulse or write pulses Pw of the write pulse waveform that is included in a recording mark making period is shifted to adjust the start position of the first pulse, wherein the start position of the first pulse is defined by a distance from a synchronization position of a reference clock that is used for forming the NRZI data, wherein the code lengths x are classified into at least four groups, and each of four code lengths x of n, n+1, n+2 and n+3 belongs to different one of the at least four groups, and wherein the width of the first pulse and the shift of the start position of the first pulse are adjusted according to the at least four groups.