| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective optical element used for reproducing and/or recording information to two kinds of optical information recording media having different used wavelengths, improving image height characteristics, correcting spherical aberration and wave surface aberration, and further correcting sine conditions, and an optical pickup device. <P>SOLUTION: This objective optical element 40 is provided with a first optical surface 41 in which a first diffraction structure 60 constituted of a diffraction ring zone 61 around an optical axis L and a step surface 62 arranged almost parallel to the optical axis to connect two diffraction ring zones is formed, and a second optical surface 42 in which a second diffraction structure 70 constituted of a diffraction ring zone 71 around an optical axis and a step surface 72 arranged almost parallel to the optical axis to connect two diffraction ring zones. The step surface of the first diffraction structure is arranged to face the optical axis side, and the step surface of the second diffraction structure is arranged to face a side opposite to the optical axis. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
