Patent ID: 7489611
Filing Date: 2009-02-10
Classification: G11B

Abstract:
1. An optical disc device for recording and reproducing information by forming marks and lands in an optical information recording medium, the optical disc device comprising: measuring means for measuring lengths of the marks and lands recorded using a reference write strategy and an alternative write strategy in which at least one parameter is varied in two or more combinations of marks and lands with respect to the reference write strategy; measurement results memory for storing a result of the measuring means; theoretical length memory for storing theoretical lengths of the respective marks and lands; deviation value computing means for computing a deviation value of each of the marks and lands by shifting the write strategy on the basis of the lengths of the marks and lands stored in the measurement results memory and the lengths of the mark and lands stored in the theoretical length memory; contractile rate computing means for computing inherent contractile rates of all marks and lands from the computed deviation value and a probability of occurrence of each of the marks and lands; variance computing means for computing a variance of the deviations by the combination of each of the marks and lands from the computed deviation value of each of the marks and lands; and write strategy setting means for setting the write strategy using the computed inherent contractile rates of all the marks and lands such that the computed variance is minimized.