Patent ID: 7719950
Filing Date: 2010-05-18
Classification: G11B

Abstract:
1. A disk drive apparatus comprising: head means for performing laser irradiation to and detection of reflected light from an optical disk recording medium in order to read data and having a focus bias mechanism for laser light and a spherical aberration correction mechanism; focus bias means for driving the focus bias mechanism to add a focus bias to a focus servo loop; spherical aberration correction means for driving the spherical aberration correction mechanism based on a spherical aberration correction value to perform spherical aberration correction; evaluation value creating means for creating an evaluation value functioning as an indicator of the quality of read signals based on reflected light information obtained by the head means; adjustment means for adjusting the focus bias and the spherical aberration correction value to optimum values based on the evaluation value created by the evaluation value creating means; and control means for determining whether data is written on at least one track of the tracks adjacent to an adjustment use range on the optical disk recording medium or not based on the reflected light information obtained by the head means and controlling an adjustment operation on the focus bias and the spherical aberration correction value by the adjustment means based on the determination result.