Optical disc, optical disc drive, optical disc recording/reproducing method, and integrated circuit

Abstract

An address format for appropriately controlling the recording linear density and the number of information recording layers is provided in order to increase the recording capacity of an information recording medium such as an optical disc or the like in a range in which a necessary S/N ratio can be guaranteed. An optical disc includes an information recording layer having a concentric or spiral track, and has a format for describing a track address, which is pre-recorded on the track or is to be added to data that is to be recorded on the information recording layer. The format includes layer information regarding the information recording layer and address information regarding the track address.

1 . An optical disc, in which a track on which data is recordable is divided into a plurality of blocks, and each block includes L pieces of sub blocks, wherein:
 on each sub block, M-bit first digital information specifying a block address of a block including the each sub block and N-bit second digital information capable of representing a numerical value equal to or larger than L are recorded;   where a value of the block address is smaller than a threshold value, the second digital information represents a value specifying a number pre-assigned to the each sub block;   whereas where the value of the block address is equal to or larger than the threshold value, the second digital information represents a value other than the value specifying the number pre-assigned to the each sub block; or   where the value of the block address is equal to or larger than the threshold value, the second digital information represents the value specifying the number pre-assigned to the each sub block; whereas where the value of the block address is smaller than the threshold value, the second digital information represents a value other than the value specifying the number pre-assigned to the each sub block,   wherein the optical disc comprises a plurality of layers on which data is recordable,   wherein:   in one of an odd-numbered layer and an even-numbered layer, where the value of the block address is smaller than the threshold value, the second digital information represents the value specifying the number pre-assigned to the each sub block; whereas where the value of the block address is equal to or larger than the threshold value, the second digital information represents a value other than the value specifying the number pre-assigned to the each sub block; and   in the other of the odd-numbered layer and the even-numbered layer, where the value of the block address is equal to or larger than the threshold value, the second digital information represents the value specifying the number pre-assigned to the each sub block; whereas where the value of the block address is smaller than the threshold value, the second digital information represents a value other than the value specifying the number pre-assigned to the each sub block.   
     
     
         2 . A reproducing method for reproducing data recorded on the optical disc of  claim 1 , the reproducing method comprising the steps of:
 detecting first and second reproduction signals from the track of the optical disc;   demodulating the first and second digital information from the first reproduction signal;   specifying information on the block address at least based on the first and second digital information; and   reproducing data in an arbitrary position of the block address based on the second reproduction signal.   
     
     
         3 . A recording method for recording data on the optical disc of  claim 1 , the recording method comprising the steps of:
 detecting a reproduction signal from the track of the optical disc;   demodulating the first and second digital information from the reproduction signal;   specifying information on the block address at least based on the first and second digital information; and   recording data at an arbitrary position of the block address.