Olympus Optical Company, Ltd.

Nobuyoshi Iwasaki

Daisuke Matsuo

Junichi Nakano

Shohei Kobayashi

A laser beam emitted from a laser source provided at a silicon substrate passes through a hologram element formed of a translucent flat plate and a grating, thereby being subjected to NA conversion executed by an NA converting lens, passing through a polarizing film of a polarization beam splitter, and converging onto a magneto-optical disk via a collimator lens and an objective. A part of back-reflection from the magneto-optical disk, which is reflected by a polarizing film of the polarization beam splitter, is reflected by a reflection surface of the splitter, then branched into two polarized light beams by a Wollaston prism, and guided to one light receiving element group. On the other hand, another part of the back-reflection, which passes through the polarization beam splitter, is branched into two beams by the hologram element and guided to the other light receiving element groups.

Optical pickup apparatus

A magneto-optical pickup includes a light source for emitting a light beam, the light beam traveling to an information recording medium along a first optical path, a first light receiving element group for detecting an error signal, a second light receiving element group for detecting a magneto-optical signal, the first and second light receiving element groups being situated substantially on one plane, a diffraction grating for diffracting light returned along the first optical path from the information storage medium, the diffracted light being directed toward the first light receiving element group, a polarization beam splitter for separating a part of the return light from the information storage medium, a beam of the separated part of return light traveling to the second light receiving element group along a second optical path, a mirror for bending the second optical path, the light beam reflected thereby being directed toward the second light receiving element group, and an anisotropic optical crystal member having an optic axis inclined to the optical axis at an angle within the range between 30&deg; and 60&deg;, the crystal member including a parallel flat plate portion, which is between the mirror for bending the second optical path and the first light receiving element group.

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Hachioji, Japan

Nobuyoshi Iwasaki