Security Document Metamaterial Authentication via Laser Ablation
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Solution Overview
Problem
Security documents face challenges due to variations in the positioning of security threads, which can lead to inconsistencies in authentication and potential forgery, as well as limitations in incorporating multiple security elements due to interference and overlapping issues.
Innovation Solution
A method involving the creation of a metamaterial by partially removing a conductive layer within the security document, using laser light to customize and authenticate the document, allowing for precise positioning and increased security feature integration without altering the document's thickness or integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If security threads are incorporated into paper substrates to enhance security, then the difficulty of forgery increases, but the positioning variations between individual documents lead to authentication inconsistencies
Solution Approach 1:
The patent replaces mechanical positioning methods with laser-based marking systems. Laser markings are applied directly to the security thread after insertion, providing precise positioning without relying on mechanical alignment during thread incorporation. This substitution of mechanical positioning with optical positioning resolves the contradiction by achieving high precision without compromising authentication consistency.
Solution Approach 2:
The patent changes the state of the security thread by applying laser markings that alter its optical, magnetic, or fluorescent properties. These parameter changes create unique authentication features that are precisely positioned and consistent across documents, overcoming the positioning variations inherent in mechanical thread insertion methods.
2Reliability
If multiple security elements are incorporated close together to increase security density, then the security level improves, but interference and overlapping between elements occur
Solution Approach 1:
The patent uses laser markings as an intermediary to differentiate between closely spaced security elements. The laser-induced modifications create distinct optical, magnetic, or fluorescent signatures for each element, allowing them to be individually identified and authenticated even when physically close together, thus preventing interference while maintaining high security density.
Solution Approach 2:
The patent applies local quality changes to security elements through targeted laser marking. Each element receives specific modifications in its optical, magnetic, or fluorescent properties, creating unique local characteristics that enable differentiation and prevent interference between closely positioned elements while maximizing security density.
3Quantity of substance
If security elements are positioned in register with other features to maximize incorporation density, then the amount of security elements increases, but the complexity of manufacturing and positioning increases
Solution Approach 1:
The patent applies laser markings to security threads after they are inserted into the substrate, rather than requiring precise positioning during insertion. This preliminary action of marking after placement simplifies the manufacturing process by decoupling thread insertion from positioning precision, allowing higher incorporation density without increasing manufacturing complexity.
Solution Approach 2:
The patent replaces complex mechanical positioning systems with laser-based marking and positioning. The laser system provides precise registration with existing document features through optical alignment, reducing mechanical complexity while enabling high quantities of security elements to be positioned accurately across the document.
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 enhances the security and authenticity of documents by enabling precise customization and authentication, reducing the risk of forgery and allowing for more efficient incorporation of security features, while maintaining the document's integrity and preventing wear.
Implementation Method 1
removing part of said conductive layer, in particular by means of laser light
Data Source
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AI summary
Method of providing a security document with a security feature, comprising the step of providing a conductive layer (22), and the step of removing part of said conductive layer (22) so as to convert at least a portion of said conductive layer into a metamaterial (31, 32) selected to provide for authentication of the security document. The invention also relates to a security document obtained with this method, and to a method of authenticating such a security document.