| 摘要 |
<P>PROBLEM TO BE SOLVED: To suppress influence of crosstalk light from an adjacent layer other than a read-out objective layer which is a recording layer of the object for reading out, with a simple structure. <P>SOLUTION: In the optical pickup device, a diffraction grating 13 has such a grating pitch P (μm) that a center space KD (μm) in the track direction between the position of a light spot of a main beam MB on a two-layer optical disk D and the position of a light spot of any one of sub-beams out of a pair of sub-beams SB<SB>1</SB>, SB<SB>2</SB>becomes larger than a radius r (μm) of the crosstalk light CR from the adjacent layer d<SB>2</SB>(or d<SB>1</SB>) other than the read-out objective layer d<SB>1</SB>(or d<SB>2</SB>) on the two-layer optical disk D. <P>COPYRIGHT: (C)2008,JPO&INPIT |
