Patent ID: 8169883
Filing Date: 2012-05-01
Classification: G11B

Abstract:
1. An optical disk comprising a plurality of information recording layers, in which data is recorded in tracks by laser light that is irradiated from one side, the tracks being provided respectively in the plurality of information recording layers; wherein the plurality of information recording layers comprise a first information recording layer, and second to N-th information recording layers (with N being an integer of two or greater) that are arranged further toward the side from which the laser light is irradiated than the first information recording layer and which are arranged in order from the side near the first information recording layer; wherein the first information recording layer comprises a read-only control data region, a first recording learning region for learning recording parameters to record data in the first information recording layer, and a first user data recording region for recording user data; wherein the read-only control data region is provided only in the first information recording layer; wherein, when taking at least one of the second to N-th information recording layers as an i-th information recording layer (with i being an integer satisfying 2≦i≦N), that i-th information recording layer comprises an i-th recording learning region for learning recording parameters to record data in the i-th information recording layer, an i-th user data recording region for recording user data, and an i-th unrecorded region that is arranged adjacent to the outer side of the i-th recording learning region an in which no data is recorded; wherein the first recording learning region and the i-th recording learning region are arranged at different radial positions, and the i-th unrecorded region and the i-th recording learning region are arranged within a region of radial positions at which the read-only control data region of the first information recording layer is provided; wherein an innermost radial position of the recording learning region of the second information recording layer is arranged at a first distance from an innermost radial position of the read-only control data region of the first information recording layer; and wherein when a second distance is a distance between an outermost radial position of the read-only control data region of the first information recording layer and an outermost radial position of the recording learning region of the second information recording layer, the second distance is shorter than the first distance.