Patent ID: 9177591
Filing Date: 2015-11-03
Classification: G11B

Abstract:
1. A focus controlling method comprising: performing aberration correction according to a change of a recording layer of a disk from a currently accessed recording layer to a recording layer desired to be accessed; changing a value of a gain of a sum signal, a gain of focus error signal, and/or a balance of the focus error signal based on an aberration correction amount that is used during the performing of the aberration correction operation between the currently accessed recording layer and the recording layer desired to be accessed; and determining characteristics of signals for use in servo control of an optical disk drive based on the gain of the sum signal, the gain of the focus error signal, and the balance of the focus error signal, wherein the changing of the value of the gain of the sum signal, the gain of the focus error signal, and/or the balance of the focus error signal comprises referring to a lookup table comprising the value of the gain of the sum signal, the gain of the focus error signal, and the balance of the focus error signal optimized based on the aberration correction amount between the currently accessed recording layer and the recording layer desired to be accessed.