Optical Disc Authentication via Interferometric Fingerprinting
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Solution Overview
Problem
Existing methods for uniquely identifying optical discs are inadequate, as they rely on limited unique information and can be compromised if their underlying principles are discovered, lacking robustness against handling and environmental deterioration.
Innovation Solution
The method involves using interferometric techniques to create a unique digital identifier based on variations in material layer thickness during the disc replication process, which are then used to authenticate the disc through an optical interference pattern comparison with stored authentication data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical marking or laser damage is used to create unique disc identifiers, then each disc can be uniquely identified, but the disc structure is damaged and the method lacks robustness against handling deterioration
Solution Approach 1:
The patent replaces mechanical/damaging identification methods (laser marking, physical defects) with an optical interference-based system. The unique identifier is created through optical interference patterns generated by natural variations in spacer layer thickness, detected by a photodetector, eliminating the need for physical damage to the disc structure.
Solution Approach 2:
The patent utilizes natural parameter variations in the spacer layer thickness during manufacturing to create unique optical interference patterns. Instead of imposing external marks or defects, the system exploits inherent dimensional variations (parameter changes) that occur naturally in the replication process to generate distinctive authentication signatures for each disc.
2Reliability
If angular orientation of randomly placed layers is measured for disc identification, then unique identification is achieved, but the method relies on limited unique information and can be compromised if the underlying principle is discovered
Solution Approach 1:
The patent replaces mechanical measurement methods (angular orientation detection of randomly placed layers) with an optical interference-based detection system. The photodetector captures optical interference patterns that encode unique disc identifiers, providing a more secure and information-rich authentication mechanism that is not easily reverse-engineered.
Solution Approach 2:
The patent transitions from measuring a single parameter (angular orientation) to utilizing multi-dimensional optical interference patterns. The interference patterns contain丰富的 information about spacer layer thickness variations across multiple dimensions and locations, significantly increasing the amount of unique authentication information available while making the system more resistant to compromise.
3Reliability
If manufacturing defects are used for disc identification, then unique identification is possible, but the method relies on limited unique information and effectiveness is reduced if the principle becomes known
Solution Approach 1:
The patent converts the natural manufacturing imperfections (spacer layer thickness variations) from potential defects into beneficial unique authentication features. Instead of relying on random defects that may be inconsistent or predictable, the system systematically captures and utilizes these variations through optical interference to create secure, unique disc identifiers.
Solution Approach 2:
The patent performs preliminary capture and storage of the unique optical interference pattern during disc manufacturing or initial authentication. This pre-established authentication signature is stored securely and used for subsequent verification, ensuring robust authentication before any potential compromise can occur.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a robust and unique authentication method that is resistant to handling and environmental deterioration, effectively preventing counterfeiting and ensuring disc authenticity by utilizing the inherent variability in spacer layer thickness across each disc.
Implementation Method 1
detecting light reflected from one data layer interfering with light reflected from at least one of the first disc surface and another data layer via a photo detector which provides a signal that varies accordingly, determining an optical interference pattern including intensity modulations of the photodetector output signal
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Authentication of discs occurs by the use of interferometric authentication data. Such authentication data of a data disc is generated based on an interference pattern associated with thickness variations of a material layer on the disc. The interference pattern represents a unique fingerprint that can be used for authentication of individual discs.