Optical recording medium
AssigneeTDK Corporation
InventorsHiroaki Takahata, Hisaji Oyake
Life of this patent
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Abstract
In an optical recording medium comprising a substrate including parallel extending lands and grooves on one surface thereof, the grooves serving as recording tracks, and the lands being formed with prepits, the height HP of the land disposed between the prepit and the groove divided by the height HL of the land in a prepit-free region, both as measured from the groove bottom, i.e., HP/HL ranges from 0.25 to less than 1. This enables to significantly increase the recording density of the medium without a substantial cost increase.
Claims3
An optical recording medium comprising a substrate including lands and grooves extending substantially parallel on one surface thereof, the grooves serving as recording tracks, and the lands being formed with prepits, wherein
- the height HP of the land disposed between the prepit and the groove and the height HL of the land in a prepit-free region, both as measured from the bottom of the groove in a cross section perpendicular to the substrate surface, satisfy the relationship:
- 0.25≦HP/HL<1.
Dependencies are inferred from the claim text.