| 摘要 |
<p>Provided is a laser machining device which can previously detect a defect area which is present on the surface of a disc-like object to be processed and form a row of portions to be processed avoiding the defect area. The beam spot of a sub-beam (SB2) on the outer peripheral side is positioned on an unprocessed area (C) in which a track is to be formed next. At the same time when a main beam (MB) is emitted onto an object to be processed (10) to thereby form a pit string thereon, the reflected light of the sub-beam (SB2) is detected and the defect area (DF) located on the unprocessed area (C) in which a track is to be formed next is detected. The position of the detected defect area (DF) is specified and position information (defect information) about the defect area (DF) is stored. In order to form the next track by using the main beam (MB), the pit string is formed avoiding the defect area (DF) on the basis of the previously-acquired defect information. While the main beam (MB) passes over the defect area (DF), the focusing control is temporality stopped so as to prevent the focus from deviating largely.</p> |
