| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which is compatibly used for a BD (Blu-ray Disk) and an HD (High-Definition Digital Versatile Disk) using the same luminous flux, by a single objective optical element, and well corrects spherical aberration caused in accordance with wavelength variation while securing light quantity of a light condensing spot required for recording/reproducing of information. and also to provide an objective optical element used for the same. <P>SOLUTION: Since at least one side of regions for a first optical disk area and a region for second optical disk area has an optical path difference giving structure for correction of a different shape from an optical path difference giving structure for distribution, compared with the case in which at least one side of regions is used as a diffraction surface, when power source wavelength is varied, spherical aberration caused in the luminous flux passing through a common region in which the optical path difference giving structure for distribution is formed, is made close to spherical aberration caused in the luminous flux passing through at least one side of regions in which the optical path difference giving structure for correction is formed, and an appropriate light condensing spot is thereby formed on an information recording surface of the first optical disk or an information recording surface of the second optical disk. <P>COPYRIGHT: (C)2010,JPO&INPIT |
