Deformable Spacer Layer for Cost-Effective Security Foils
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Solution Overview
Problem
The existing production of security documents, particularly banknotes, faces challenges in incorporating cost-effective optically variable devices (OVDs) that are difficult to counterfeit, especially when using polymer film substrates, as traditional methods are expensive and wasteful, limiting the scalability and effectiveness of security features.
Innovation Solution
The development of optically variable devices featuring a deformable spacer layer that can transition between compressed and relaxed states upon mechanical pressure, altering optical interference structures and color-shift properties, allowing for selective activation of security features, which can be integrated into various substrates including polymer films, enhancing security without significant material wastage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vacuum deposition methods are used to manufacture optically variable devices on polymer film substrates, then the security features exhibit desired optical properties, but the manufacturing cost is high and material wastage is significant
Solution Approach 1:
The patent changes the manufacturing parameters by switching from vacuum deposition to a solution-based printing process. This involves dissolving reflective and absorptive materials in a binder and applying them through printing techniques, fundamentally altering how the optically variable device is manufactured to reduce cost and waste while maintaining security effectiveness
Solution Approach 2:
The patent replaces expensive vacuum-deposited metal layers with cheaper printed material compositions. The reflective and absorptive materials are applied in a cost-effective manner using printing processes, eliminating the need for expensive vacuum deposition equipment and reducing material costs significantly
2Strength
If optically variable devices are embedded into polymer film substrates, then security features are protected and durable, but the manufacturing process becomes more complex and costly compared to paper substrates
Solution Approach 1:
The patent merges the manufacturing of the optically variable device with the substrate preparation process. By printing the reflective and absorptive material compositions directly onto the polymer film substrate in a single integrated process, the patent eliminates separate manufacturing steps, reducing overall process complexity while maintaining durability
Solution Approach 2:
The patent uses composite material compositions comprising reflective materials, absorptive materials, and binders. These composite materials are printed directly onto the substrate, creating a integrated structure that combines the substrate and security feature manufacturing into one process, simplifying production while ensuring durability
3Ease of manufacture
If conventional security print technologies are used, then manufacturing is simple and cost-effective, but the security documents become increasingly susceptible to counterfeit
Solution Approach 1:
The patent introduces dynamic optical properties to the security document by creating an optically variable device that changes appearance based on viewing angle or lighting conditions. This dynamic behavior, achieved through the layered structure of reflective and absorptive materials, provides counterfeit resistance while maintaining manufacturing simplicity through printing processes
Solution Approach 2:
The patent utilizes color changes as a security feature by positioning absorptive material layers to selectively absorb certain wavelengths of light. This creates optical variable effects where the document appears different under various lighting conditions or viewing angles, providing anti-counterfeit protection while using simple printing methods to apply the color-changing materials
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 solution provides a cost-effective and scalable method to embed secure, optically variable security features into security documents, enabling easier detection of authenticity and reducing manufacturing costs while maintaining high security standards.
Implementation Method 1
a deformable spacer layer which can be deformed to reduce the thickness of the optical interference structure upon application to the material of a mechanical pressure
Implementation Method 2
an optical interference structure comprising a reflector layer, a deformable spacer layer and an absorber layer
Implementation Method 3
an absorber layer which transmits light incident thereupon
Data Source
Figure 1a~1c
Figure 2a~2c
Figure 3a~3c
AI summary
Security documents often incorporate optically variable devices to prevent or hinder counterfeiters. Disclosed herein are layered optically variable devices such as colour-shift foils, and methods for their production and use. Such devices afford new techniques for a user of a security document to check quickly and easily whether the security document is a legitimate document or a counterfeit copy.