OPTICAL INFORMATION RECORDING AND REPRODUCING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an optical information recording and reproducing device which can exactly record and reproduce information data along a guide track for tracking formed on an optical recording medium. SOLUTION: The laser beam of a 1st light source 11 for record reading and the laser beam of a 2nd light source 12 for tracking control are composited while having their optical axes aligned with each other, and converged by an objective 16 to irradiate an optical disk 17 where a plurality of recording layers and tracking guide layers are formed with the converged laser beam. At this time, the depth of focus of the 2nd laser beam is made larger than the focus movement range of the 1st laser beam obtained by adding the depth of focus of the 1st laser beam to the distance between the recording layers formed most distantly from and most closely to the incidence surface of the disk respectively.