| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve a problem that, in order to identify a plurality of discs by switching laser light beams having a plurality of wavelengths, in a focus search operation of bringing a laser light beam to a focus on a recording layer of an optical disc, when the laser light beam is not suitable for the optical disc to which the laser light beam is inserted, a focus search operation needs to be executed again after the laser light beam is switched to another laser light beam, so that it takes a long time period to start up an optical disc apparatus. <P>SOLUTION: When an optical disc 1 is identified by a circuit 16 for detecting a recording layer 1a of the optical disc 1 and a circuit 23 for determining whether a laser light beam that is currently turned on is suitable for the recording layer 1a, a laser emission control circuit 21 switches laser light beams having a plurality of wavelengths that are to be turned on, at time intervals that are sufficiently short for a time interval in which a focus search is performed for one time. Thereby, it is possible to identify an optical disc by performing a focus search operation for one time and attain focus, thereby reducing the startup time. <P>COPYRIGHT: (C)2009,JPO&INPIT |
