Patent ID: 7551536
Filing Date: 2009-06-23
Classification: G11B

Abstract:
1. 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 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 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, wherein as to two codes, which have code lengths m and m+1, respectively, and which have the same number of write pulses Pw and the same number of periods with a bottom power level Pb between two write pulses Pw in the recording mark making period of their write pulse waveforms, the step (B) includes determining the write pulse waveforms so as to satisfy the inequality: (pulse width of code length m)<(pulse width of code length m+1) where the pulse width of code length m is the width of an arbitrary Kth period with the bottom power level Pb included in the recording mark making period corresponding to the code length m and the pulse width of code length m+1 is the width of the Kth period with the bottom power level Pb included in the recording mark making period corresponding to the code length m+1, and wherein K=1.