| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an optical pickup apparatus correcting aberration with a simple configuration, a recording/reproducing apparatus provided with the optical pickup apparatus, an optical element, an information recording/reproducing method, an optical system, a lens, a diffractive optical system for an optical disk, a reproducing apparatus and an objective lens for the optical pickup apparatus. <P>SOLUTION: The optical pickup apparatus includes an optical surface having a ring-zonal diffraction lens provided on a refractive plane of the objective lens 1 and cancels action between a diffractive surface and the refractive plane to each of light sources 11, 12 and 13 having three wavelengths different from each other to correct spherical aberration. Loss of a light quantity can be reduced by using the first-order diffracted light as the diffraction light of light from the light sources 11, 12 and 13 having the three wavelengths. The objective lens has a diffraction pattern on at least one surface and first-order diffracted light from the diffraction pattern is used in reproduction of a plurality of recording mediums when luminous fluxes from the light sources having different wavelengths are condensed on an information recording surface. The used diffraction light is plus first-order diffracted light or minus first-order diffracted light according to the conditions of the recording mediums. <P>COPYRIGHT: (C)2010,JPO&INPIT |
