| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect a good track error signal from an optical recording medium in which a track error signal is not obtained well by a push-pull method. <P>SOLUTION: With a diffraction optical element 17, a pair of subspots are formed in positions shifted ±n×Tp/2 from the spot center of the main spot in a direction orthogonal to the recording track, a pair of astigmatic sub-luminous fluxes whose polarities are reverse to each other are received by a pair of sub-light receiving parts 19, 20 having a pair of light receiving surfaces divided into two by a division line corresponding to a direction orthogonal to a recording track, and a track error signal is generated based on optical detection signals received and output by the pair of sub-light receiving parts 19, 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
