| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve information recording or information reproducing with an optical pickup for a variety of recording media including the recording medium using an optical beam of the same wavelength. <P>SOLUTION: An objective lens 6, designed so that an optical beam L3 is made to be converged appropriately on a recording plane of a blue ray disc, and an optical element 8, which gives phase difference distribution to an optical beam L2 and does not give the phase difference distribution to the optical beam L3, are combined. An objective lens 7, designed so that the optical beam L3 is made to be converged appropriately on the recording plane of other optical discs, and an optical element 9, which gives the phase difference distribution to an optical beam L1 and does not give the phase difference distribution to the optical beam L3, are also combined. With these two sets of the combination, the information recording or the information reproducing is performed for four kinds of the recording media, such as a CD, a DVD, the blue ray disc and other optical discs. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
