| 摘要 |
PURPOSE:To provide a small-sized and inexpensive optical pickup for magneto- optical signal realizing a reciprocal optical paths separating function and a focus error detecting function by one piece of hologram. CONSTITUTION:A beam outgoing from a semiconductor laser chip 2 is converged on an optical disk 11 and the reflected beam from the optical disk 11 is diffracted in any direction of 45 deg., 135 deg., 225 deg., 315 deg. for the polarizing direction of a linear polarization from a light emitting element 2 by the action of the hologram 8 formed on the top surface 1a of a transparent optical member 5. This pickup is constituted so that the return diffracted beam 14 is device effectively to a P polarization component and an S polarization component by a polarization separation membrane and a polarization separation auxiliary member 16, and the P polarization component is detected by a first light receiving sensor 23, and the S polarization component is detected by a second light receiving sensor 29, and a focus error signal and a magneto-optical signal are detected from an output difference between the first light receiving sensor 23 and the second light receiving sensor 29. |
