| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device to stabilize a push-pull signal of a sub-beam by stray light, while being compatible with a double-layer optical information recording medium. <P>SOLUTION: The device is provided with a semiconductor laser 102 emitting a light beam L1 having wavelength corresponding to recording/reproducing of the double-layer optical information recording medium 101, a diffraction grating 103 diffracting the light beam L1 of wavelength to a main beam of 0th order diffraction light and a sub-beam of ±1st order diffraction light, a 1/4 wavelength plate 104 polarizes the light beam L1 of linear polarization (p polarization) to circular polarization, a hologram element 105 diffracting the light beam L1 reflected by the double-layer optical information recording medium 101, a first light receiving element group 106 receiving diffracted light from the hologram element 105, and a second light receiving element group 107 or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT |
