Patent ID: 7224660
Filing Date: 2007-05-29
Classification: G11B

Abstract:
1. An optical disk device for forming marks and spaces on an optical information recording medium, and recording or reproducing information, comprising: measurement means for measuring lengths of marks and spaces recorded using a reference write strategy and lengths of marks and spaces recorded using a changed write strategy in which at least one of setting parameters is changed in various combinations of marks and spaces with respect to the reference write strategy; measurement value storage means for storing results of the measurement; theoretical length storage means for storing-theoretical lengths of the marks and the spaces; deviation calculation means for calculating deviations of the marks and the spaces recorded using the changed write strategy, based on the measured lengths of the marks and the spaces stored in the measurement value storage means and the theoretical lengths of the marks and the spaces stored in the theoretical length storage means; and expansion and contraction amount calculation means for calculating unique amounts of expansion and contraction of the marks and the spaces, based on the calculated deviations and probabilities of existence of the marks and the spaces.