| 摘要 |
PURPOSE: To enable an optical pickup device to perform stable tracking control of an optical information recording medium of current use and next generation by freely selectively providing a tracking error signal detecting system in accordance with optical information recording media having different track pitches. CONSTITUTION: A three-beam type detecting system 12 processes detected signals G-J obtained from the light receiving areas of bisected photodetectors 10d, 11e of a light receiving part 11 and calculates a tracking error signal. On the other hand, a differential pushpull type detecting system 13 processes detected signals A-D, G-J obtained from the light receiving areas of a quadripartite photodetector 10a, bisected photodetectors 10d, 10e and calculates a tracking error signal. The detecting system 12 and the detecting system 13 are changed over by means of a switch 14 according to an optical information recording medium with different track pitch. Consequently, as to a current optical information recording medium and an optical information recording medium of next generation having different track pitch from each other, the change of the constitution of optical system is not necessary and the stable detection of a tracking error signal can be performed. |
