Optical disc with protection code, method for obtaining the protection code and respective apparatus for reading of data
AssigneeThomson Licensing
InventorGael Pilard
Life of this patent
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Abstract
The optical disc comprises a substrate layer, a read-only data layer having a pit/land data structure including user data and control data arranged in tracks on the substrate layer, and a nonlinear layer with a super-resolution structure disposed on the data layer, wherein the control data are correctly readable only by including a reverse rotation of the disc. The control data include in particular a protection code for the disc, for example a copy protection code, so that the user data of the disc are only readable after reading of the control data.
Claims15
Optical disc comprising
- a substrate layer,
- a read-only data layer having a pit/land data structure including user data and control data arranged in tracks on the substrate layer, and
- a nonlinear layer with a super-resolution structure disposed on the data layer, wherein
- the control data are correctly readable only by including a reverse rotation of the disc.
Method for reading data from an optical disc comprising a substrate layer, a read-only data layer having a pit/land data structure including user data and control data arranged in tracks on the substrate layer, and a nonlinear layer with a super-resolution structure disposed on the data layer, comprising the steps:
- reading the control data by rotating the optical disc in forward direction for obtaining a first data signal,
- reading the control data by rotating the optical disc in reverse direction for obtaining a second data signal, and
- calculating a protection code for the optical disc from the first and second data signal.
Dependencies are inferred from the claim text.