OPTICAL DISC MEDIUM, OPTICAL DISC DEVICE, OPTICAL DISC REPRODUCTION METHOD AND INTEGRATED CIRCUIT

摘要

It is an object to provide an address format that properly controls a rec ording line density and the number of information-recording layers for an in formation-recording medium to increase a recording capacity of the informati on-recording medium such as an optical disc in the range for making it possi ble to secure a necessary SN ratio. The optical disc is provided with an inf ormation-recording layer including concentric circles or spiral-shaped track s, and has a format for describing track addresses recorded on a track in ad vance or added to data to be recorded on the information-recording layer. Th e format includes layer information on the information recording layers and address information on the track addresses. In a first optical disc having a first recording density, the layer information of the first optical disc is described by the first number of bits and the address information of the fi rst optical disc is described by the second number of bits. In a second opti cal disc having a second recording density that is larger than the first rec ording density, the layer information of the second optical disc is specifie d by the number of bits that is less than the first number of bits and the a ddress information of the second optical disc is specified by the number of bits that is more than the second number of bits. The total number of bits o f the layer and address information of the second optical disc is equal to t he sum of the first and second numbers of bits.