| 摘要 |
In a double density CD for an optical pickup device including a laser with a wavelength of lambdmum and an objective lens (4) with a numerical aperture of NA, the expression 0.7<TP/(lambd/NA)<0.8, where TP is a track pitch in mum and/or the expression 0.40<L/(lambd/NA)<0.45, where L is a minimum pit length in mum are/is satisfied. Thus, jitter is suppressed and the reproduction characteristic is improved.
|
