| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide: an objective lens being applicable to an optical pickup device for recording and/or reproducing information on a plurality of types of optical information recording media using luminous fluxes with different wavelengths, and having weak wavelength dependence of spherical aberration; an optical pickup device using the objective lens; and an optical information recording and reproducing device in which the optical pickup device is mounted. <P>SOLUTION: The objective lens according to the present invention is an objective lens used for the optical pickup device. On one surface of the lens having power, the objective lens has a superposed structure superposing a first optical path difference addition structure in which spherical aberration varies in the direction of insufficient correction when the wavelength of an incident luminous flux is longer, and a second optical path difference addition structure in which spherical aberration varies in the direction of excessive correction when the wavelength of an incident luminous flux is longer. <P>COPYRIGHT: (C)2012,JPO&INPIT |
