Metameric Security Devices Using Active Materials
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Solution Overview
Problem
Current Interference Security Image Structures (ISIS) are vulnerable to reproduction and detection by the general public due to their passive nature, as iridescent consumer products have made basic interference-based devices obsolete, and there is a need for enhanced anti-counterfeiting measures.
Innovation Solution
Incorporating an active component using electrochromic, thermochromic, or piezochromic materials into the ISIS, which requires an external energy source to change its appearance, creating a metameric device with dynamic optical effects that are more challenging to duplicate, adding a second level of authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If basic interference-based ISIS devices are used, then the device structure is simple and fabrication costs are low, but the anti-counterfeiting performance deteriorates due to vulnerability to reproduction and availability of iridescent consumer products
Solution Approach 1:
The patent combines multiple materials with different optical properties (iridescent interference material and non-iridescent color-matched material) into a single composite security device. This creates a multi-layered structure where each material contributes unique characteristics that are difficult to replicate, thereby enhancing anti-counterfeiting performance while maintaining reasonable structural complexity
Solution Approach 2:
The patent applies different optical properties to different regions of the security device. The iridescent material provides angle-dependent color changes in specific areas, while the non-iridescent material provides consistent color reference in other areas. This local differentiation creates complex verification requirements that improve security without requiring the entire device to be overly complex
2Ease of operation
If iridescent ISIS devices are used, then the observation angle dependent optical effect provides efficient detection means, but the anti-counterfeiting performance deteriorates due to availability of iridescent consumer products
Solution Approach 1:
The patent utilizes color changes in two distinct ways: (1) the iridescent material changes color based on observation angle, providing a dynamic visual effect that is easy to detect; (2) the non-iridescent material provides a stable color reference that does not change with angle. The combination creates a verification system where both the changing and stable color properties must be present, making counterfeiting more difficult while maintaining ease of detection
Solution Approach 2:
The patent changes the optical parameters of the security device by incorporating materials with different iridescence properties. The iridescent component provides angle-dependent color variation for easy detection, while the non-iridescent component provides parameter stability (consistent color) that prevents replication by standard iridescent consumer products. This dual-parameter approach resolves the contradiction between detectability and security
3Reliability
If metameric device with non-iridescent material is used, then the color reference improves detection for observers with color vision deficiencies, but the device loses the angle-dependent color change effect
Solution Approach 1:
The patent merges two previously separate concepts (iridescent ISIS and non-iridescent color reference) into a single integrated device. The non-iridescent material provides reliable color reference for accessibility, while the iridescent material contributes angle-dependent color changes for enhanced security. Both optical effects coexist in the same device, allowing it to serve multiple functions simultaneously
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
The integration of active materials enhances the anti-counterfeiting performance by providing a dynamic and complex optical effect, making it harder to replicate and improving detection, especially for observers with color vision deficiencies, while also reducing fabrication costs through optimized filter design.
Implementation Method 1
Incorporating an active component using electrochromic, thermochromic, or piezochromic materials into the ISIS, which requires an external energy source to change its appearance
Implementation Method 2
Incorporating an active component using electrochromic, thermochromic, or piezochromic materials into the ISIS
Implementation Method 3
Incorporating an active component using electrochromic, thermochromic, or piezochromic materials into the ISIS
Implementation Method 4
an ISI structure which changes color as a function of angle of viewing
Implementation Method 5
Holograms and ISIS's are part of a specific category of devices termed iridescent, meaning that their appearance is dependent on the conditions under which they are observed
Implementation Method 6
two objects which display the same color under a specific illuminant and for a specific observer are termed metameric if their reflection or transmission spectra differ in the visible spectrum
Data Source
AI summary
An integrated security structure is provided employing an external source of energy to change the appearance of the structure rendering the structure more challenging to duplicate due to its complexity. The security structure includes a substrate forming part of a bank note, identification document, or other security device; an active device within the substrate changing color between at least two colors wherein a color of the substrate surrounding the active device matches one of the at least two colors to form a metameric device. At least one Interference Security Image Structure (ISIS) is configured to be metameric with a bleached state of the active device and is therefore invisible at normal incidence. Another ISIS is metameric with the colored state of the electrochromic device and consequently becomes invisible during coloration. When the whole device is tilted, both ISIS's change color while the rest of the device essentially remains the same.