| 摘要 |
An optical recording medium wherein a laser beam at a wavelength lambda is irradiated and recording and reproducing of information are performed by optical power modulation of binary or more, and when the refraction index of the first substrate being n<SUB>1</SUB>, the refraction index of the intermediate layer being n<SUB>2</SUB>, the groove depth, the groove width and the track pitch of the first information layer being d<SUB>1</SUB>, w<SUB>1 </SUB>and p<SUB>1 </SUB>respectively and the groove depth, the groove width and the track pitch of the second information layer being d<SUB>2</SUB>, w<SUB>2 </SUB>and p<SUB>2 </SUB>respectively, the following conditions are satisfied. <?in-line-formulae description="In-line Formulae" end="lead"?>4lambda/16n<SUB>1</SUB><=D<SUB>1</SUB><=7lambda/16n<SUB>1 </SUB><?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>lambda/16n<SUB>2</SUB><=D<SUB>2</SUB><=3lambda/16n<SUB>2 </SUB>or 4lambda/16n<SUB>2</SUB><=D<SUB>2</SUB><=7lambda/16n<SUB>2 </SUB><?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.2<=w<SUB>1</SUB>/p<SUB>1</SUB><=0.55 <?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.2<=w<SUB>2</SUB>/p<SUB>2</SUB><=0.55 <?in-line-formulae description="In-line Formulae" end="tail"?>
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