| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain an optical pickup apparatus capable of compensating an aberration by simple constitution, a recording and reproducing apparatus provided with the optical pickup apparatus, an optical element, a method for recording/reproducing information, optical system, lenses, a diffraction 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 obtained by forming a diffraction ring band lens on the refractive surface of the objective lens 1 and compensates a spherical aberration by offsetting the action of a diffractive surface and that of a refractive surface in each of light sources 11, 12, 13 having three respectively different wavelengths. Further, loss of light quantity can be reduced by using primary diffraction light beams as diffraction light beams of light beams from the light sources 11, 12, 13 having three wavelengths. The objective lens 1 has a diffraction pattern at least on one surface, and in converging light beams from the light sources having different wavelengths onto an information recording surface, the primary diffraction light from the diffraction pattern is used for the reproduction of a plurality of recording media. According to the conditions of the recording media, diffraction light beams to be used become + primary diffraction light beams together or - primary diffraction light beams together. <P>COPYRIGHT: (C)2007,JPO&INPIT |
