| 摘要 |
PURPOSE:To provide a small-sized and inexpensive optical pickup for magneto- optical by realizing three functions of a condensing function, a reciprocal path separating function and a focus error detecting function by one piece of composite hologram. CONSTITUTION:A beam outgoing from a semiconductor laser chip 2 is converged on an optical disk 9, and a reflection beam from the optical disk 9 is diffracted in any direction of 45 deg., l35 deg., 225 deg., 315 deg. for the polarization direction of linearly polarized light of the semiconductor laser chip 2 by the action of a composite hologram 8 formed on the first surface 5a of a transparent optical guide member 5. By detecting the P polarization component of the return path diffracted beams 12 by a first light receiving sensor 16, and detecting the remaining S polarization component by a second light receiving sensor 22, a focus error signal and a recording signal are detected by a difference between the first light receiving sensor 16 and the second light receiving sensor 22. |
