OPTICAL PICKUP, OPTICAL DISK DRIVE DEVICE, OPTICAL INFORMATION RECORDING DEVICE, AND OPTICAL INFORMATION REPRODUCTION DEVICE

摘要

An optical pickup, an optical disk drive device, an optical information recording device, and an optical information reproduction device in which a reproduction signal, a focus error signal, and a gap error signal can be detected with high accuracy when information is recorded/reproduced on/from an optical information medium having a plurality of information recording layers. The optical pickup includes a focusing lens group (7) that includes a solid immersion lens (8) and focuses the light; a first detection lens (11) that focuses the reflected light from an optical information medium (9) on a first detector (12), and a second detection lens (13) that focuses the reflected light from the flat surface portion of the solid immersion lens (8) on a second detector (14). The optical magnification ratio M of the first optical system including the focusing lens group (7) and the first detection lens (11) and the optical magnification ratio m of the second optical system including the focusing lens group (7) and the second detection lens (13) satisfy the condition M>m.