Optical disk drive

Abstract

An optical disk drive includes a pickup head, a recording/reproducing circuit, a servo circuit, a driver, a thread motor, a spindle motor, and a controller. An optical disk has a first area and a second area for which different tracking methods are to be used. The controller may causes the pickup head to make a seek for a target address in the first area from a position in this area that is farther from the boundary between the two areas than the address. The controller calculates the target address by detecting the number of times the reflection intensity of the optical disk changes during the seek, for example. If the controller can perform no tracking servo control after the seek is made, and if the calculated address is located in a critical region, the controller immediately causes the pickup head to make a seek by a specified number of addresses toward the position farther from the boundary. After this seek is made, the controller performs tracking servo control again.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an optical disk drive according to an embodiment of the present invention;

FIG. 2 is a plan view of an optical disk (a DVD-RAM) for use with this embodiment, showing the different areas on the disk;

FIG. 3 is a flowchart of the processing after a first seek according to this embodiment; and

FIG. 4 is a flowchart of the processing after a first seek according to another embodiment of the present invention.

Claims

1. An optical disk drive comprising: a main body;a pickup head for radiating a laser beam to a beam position on an optical disk set on the main body, the disk having a plurality of tracks;a controller for performing tracking servo control for causing the beam position to follow the tracks;a disk discriminating means for determining whether the optical disk has areas of a first area and a second area for which the tracking servo control is to be performed by a first method and a second method respectively, some of the tracks being formed in the first area, the other tracks being formed in the second area;a seeking means for causing the pickup head to make a seek; and,an estimating means for estimating the beam position where a laser beam is radiated from the pickup head stopping after the head is moved to make a first seek by the seeking means; wherein;the seeking means being adapted to cause the optical head to make a second seek toward a direction of moving away from a boundary between the areas, on the area including a target of the first seek, under all the conditions of the following A-D, after the first seek is made; and,the controller being adapted to perform the tracking servo control after the second seek is made.

2. The optical disk drive according to claim 1 wherein, if the estimated beam position is not inside the critical region after the first seek is made, the controller tries the tracking servo control again at the beam position where the laser beam is radiated from the pickup head stopping after the first seek is made.

3. The optical disk drive according to claim 1 wherein the two areas of the optical disk includes a rewritable area of the first area and an embossed area of the second area inside the first area, the rewritable area includes a lead-in-zone rewritable area and a data-zone rewritable area, and the specified critical region includes the embossed area and the lead-in-zone rewritable area.