| 摘要 |
The invention concerns a multilayer optical data storage medium comprising a first layer and a second overturned layer, said first and second layers being coupled each other by the interposition of an optically neutral coupling layer, said first and second layers both defining a focal reading plane, readable by a standard driving system, the data distribution of the data on the focal plane of said first layer being such to provide a zone lacking the data, to which zone corresponds the presence of data on the focal plane of the second layer, in such a way that the player, loosing the focal plane on the first layer individuates the focus signal on the second layer. |
