Patent ID: 7486604

Claim:
An optical disk device for recording or reproducing information on or from an optical information recording medium by forming marks and spaces on the optical information recording medium, the optical disk device comprising: a jitter value measurement unit for measuring a jitter value of a reproduction signal; a measurement unit for measuring lengths of marks and spaces that are recorded on the optical information recording medium using a reference write strategy or a write strategy having at least one set parameter varied with respect to the reference write strategy; a measured value memory for storing the measured lengths of the marks and the spaces, and a theoretical length memory for storing theoretical lengths of the marks and the spaces; a deviation value calculator for calculating deviation values of the marks and the spaces from the varied write strategy, based on the lengths of the marks and the spaces stored in the measured value memory and the theoretical lengths of the marks and the spaces stored in the theoretical length memory; a flexibility amount calculator for calculating amounts of intrinsic flexibility of the marks and the spaces using the calculated deviation value and probabilities of presence of the marks and the spaces; a correction value calculator for calculating a correction value for the reference write strategy based on the calculated amounts of intrinsic flexibility and the probabilities of presence of the marks and the spaces so that the deviation values of the marks and the spaces fall within a predetermined range; and a jitter value calculator for calculating a jitter value based on the deviation values acquired from the calculated correction value calculated by the correction value calculation unit, the measured jitter value measured before calculation of the correction value by the jitter value measurement unit, and a number of samples when information is recorded using the write strategy set by a write strategy setting unit.