Patent ID: 8189449

Claim:
A multilayer optical information medium comprising three or more information layers, wherein: address information indicating positions in each of the information layers is recorded in a helical manner; the information layers comprise at least one I to O layer in which values representing addresses in the address information increase from an inner perimeter section toward an outer perimeter section, and at least one O to I layer in which the values representing the addresses in the address information increase from the outer perimeter section toward the inner perimeter section; the I to O layer and the O to I layer are laminated alternately, or a combination of two or more of the I to O layers laminated to each other and a combination of two or more of the O to I layers laminated to each other are laminated alternately; all of the I to O layers have substantially the same address information and all of the O to I layers have substantially the same address information; each of the information layers has layer information and the address information; the layer information and the address information of the I to O layer and the layer information and the address information of the O to I layer are bit-inverted versions of each other; a group is formed by one of the I to O layer and one of the O to I layer being laminated to each other, or a group is formed by one of the combinations of two or more of the I to O layers laminated to each other and one of the combinations of two or more of the O to I layers laminated to each other being laminated to each other, and a group number is assigned to the group; and each of the information layers is identified by parameters including the group number, and wherein the group number is stored in a frame different from frames that store the layer information and the address information.