| 摘要 |
A limited-use Digital Versatile Disc (DVD) includes a storage layer for storing content data and control key data. At least one mark of photosensitive dye is disposed on the disc exterior to the storage layer and over at least a portion of the control key data. In one embodiment, the mark is initially transparent to allow a DVD player to read the control key data. The mark changes from clear to become opaque when it is exposed to DVD reader laser light for a cumulative period of time. This change in the optical property of the mark and the configuration of the control key data prevents further reading of the content data after predetermined reading and playback usage of at least some of the content data is permitted. In another embodiment, the mark is initially opaque to initially prevent the successful reading of the control key data, and permanently changes to transparent when exposed to DVD reader laser light for a cumulative period of time.
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