OPTICAL INFORMATION RECORDING MEDIUM AND PRODUCTION METHOD OF THE SAME
In a single-sided multi-layer optical disk, “n” information layers are formed so that sector address portions ( 9, 11 ) do not overlap with each other in a stack direction in a combination of adjacent information layers ( 1, 4 ) and an optical separating layer ( 3 ) is disposed between the information layers. Thereby, signals of the sector address portion can be reproduced stably without being affected by the sector address portions of the adjacent information layer(s).
1 . A single-sided multi-layer optical information recording medium comprising “n” (n≧2) information layers which are formed on a substrate and on and from which a signal can be recorded and reproduced by a laser beam that is applied through the substrate,
wherein an optical separating layer is formed between the information layers, each of the “n” information layers has a sector structure having sector address portions and data areas for recording information signals, the sector address portion and the data area are divided in a circumferential direction, and the sector address portions of each information layer do not overlap with at least the sector address portions of the adjacent information layer(s) in a direction of stack of information layers.
2 . The optical information recording medium according to claim 1 , wherein the sector address portions of each information layer do not overlap with sector address portions of any other information layers in the direction of stack of information layers.
3 . The optical information recording medium according to claim 1 , wherein “n”=2.
4 . A method for producing an optical information recording medium comprising “n” (n≧2) information layers which are formed on a substrate and on and from which layers a signal can be recorded and reproduced by a laser beam that is applied through the substrate, which comprises:
forming the information layer which has a sector structure having sector address portions and data areas for recording information signals, the sector address portion and the data area being divided in a circumferential direction;
forming an optical separating layer which is to be disposed between the information layers; and
positioning the sector address portions of each information layer so that they do not overlap with at least the sector address portions of the information layer(s). that is adjacent to the each information layer in a direction of stack of information layers.