Patent ID: 7907502
Filing Date: 2011-03-15
Classification: G11B

Abstract:
1. An optical information recording medium comprising: a substrate; n information recording layers provided on the substrate; and spacer layers, each of which is provided so as to be interposed between the information recording layers, wherein each of (n−1) or more of the information recording layers has a layer number information part containing layer number information, the layer number information part being formed in correspondence with one or more recording marks X, where n represents an integer of not less than 2, and the layer number information is information used for determining which a given information recording layer is among the n information recording layers, the one or more recording marks X includes at least either a groove or a pit, each recording mark X has a length in a circumferential direction longer than a length in a circumferential direction of a recording mark Y used for recording another information in the information recording layers, and each of the recording marks X is formed with the groove whose lengthwise direction extends in the same direction as a radial direction of the optical information recording medium.