| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical element which can be applied to recording/reproducing for four kinds of optical recording media, and has high diffraction efficiency and more enhanced optical performance, and to provide an optical pickup device using the optical element. <P>SOLUTION: The optical element 11 includes a first diffraction part 11d and a second diffraction part 11e. The first diffraction part 11d is obtained by sequentially laminating a first member 11a of isotropic materials, a second member 11b with a refractive index different depending on an incident polarization direction, and a third member 11c of the isotropic materials, and by being arranged at a boundary between the first member 11a and the second member 11b. A second diffraction part 11e is provided at the third member 11c. The optical element 11 is arranged at the front of a single objective lens and a polarization direction of incident light of the optical element 11 is switched thereby the optical element 11 adapts to the optical recording medium of four kinds. <P>COPYRIGHT: (C)2008,JPO&INPIT |
