US 7,480,219 B2 · Method and apparatus for calculating a variation per track of a focus error to control the tilt of a disk

Abstract

Disclosed is a tilt controlling method and apparatus in which an FE signal track at a point where an RF signal is the maximum or an RE signal track at a point where a jitter is the minimum is detected as a tilt control signal to induct a DC component according to the disk shape and an AC component according to the surface vibration of the disk. Further, the fact is used that an RF envelope has a maximum value when the disk is parallel to an object lens or there is no tilt. Thus, in a tilt initialization step, a tilt track as the RF Max. is obtained for one rotation and the central potential of this track is set as a tilt control reference voltage, and when the RF envelope becomes a phase corresponding to a condition of a controller or a differential value of the RF envelope in the tilt window signal becomes a desired phase, tilt control is started so that the RF envelope always has the maximum value.

Claims9

Dependent claims

A tilt controlling method comprising the steps of:

detecting a trace of a focus error at the maximum value of an RF signal or at the minimum value of jitter when a focus is on;
detecting the maximum value and the minimum value of the focus error;
and
calculating a variation per physical track of the focus error by using the maximum and minimum values of the focus error to control the tilt using the variation.

1 more element

Dependencies are inferred from the claim text.

Method and apparatus for calculating a variation per track of a focus error to control the tilt of a disk

Life of this patent

Method and apparatus for calculating a variation per track of a focus error to control the tilt of a disk

Life of this patent

Abstract

Claims9