| US 7,366,065 B2 | ||
| Optical disk apparatus and an optical disk recording and reproducing method | ||
| Nobuhiro Takeda, Tokyo (Japan); and Motoyuki Suzuki, Yokohama (Japan) | ||
| Assigned to Hitachi Ltd., Tokyo (Japan); and Hitachi-LG Data Storage, Inc., Tokyo (Japan) | ||
| Filed on Nov. 12, 2004, as Appl. No. 10/986,169. | ||
| Claims priority of application No. 2003-413395 (JP), filed on Dec. 11, 2003. | ||
| Prior Publication US 2005/0128901 A1, Jun. 16, 2005 | ||
| Int. Cl. G11B 7/00 (2006.01) | ||
| U.S. Cl. 369—44.29 [369/44.35] | 6 Claims |
| 1. A disk recording and reproducing method for an optical disk apparatus, in which a reproducing operation is performed under
servo control of an actuator in a servo loop of continuous servo type, the actuator controlling an objective lens, a low-speed
recording operation is performed under servo control of the actuator controlling the objective lens in a servo loop of sample-and-hold
type and a high-speed recording operation is performed under servo control of the actuator controlling the objective lens
in a servo loop of average servo type, the method comprising:
a first step of applying a first disturbance signal to the servo loop of continuous servo type at the time of reproducing
operation and observing a first learning servo signal of average type produced based on the first disturbance signal;
a second step of applying a second disturbance signal equivalent to the first disturbance signal to the servo loop of sample-and-hold
type at the time of low-speed recording operation and observing a second learning servo signal of average type produced based
on the second disturbance signal;
a third step of setting the gain of the servo loop of average servo type based on the result of comparison between the first
learning servo signal and the second learning servo signal; and
a fourth step of performing the high-speed recording operation under servo control of the servo loop of average servo type
with the gain set by the third step.
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