Security Device Asymmetric Optical Layers
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Solution Overview
Problem
Existing security devices with optically variable effect generating relief structures, such as holograms and diffraction gratings, lack sufficient security level to prevent counterfeiting, as they often provide the same visual effect from both sides, making them easier to imitate.
Innovation Solution
A security device comprising a first transparent layer with an optically variable effect generating relief structure, a reflection enhancing layer that follows the relief structure's contour, and a second transparent layer with a limited lateral extent, where the first and/or second transparent layers contain optically effective substances, creating different appearances when viewed through each layer, providing a unique visual effect from each side.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single transparent layer with optically variable relief structure is used, then the device structure is simple and easy to manufacture, but the security level is insufficient because the same visual effect appears from both sides
Solution Approach 1:
The single transparent layer is divided into two separate transparent layers (first and second transparent layers), each containing optically effective substances. This segmentation allows each layer to contribute differently to the optical effect when viewed from opposite sides, thereby enhancing security while maintaining manufacturing feasibility through established lamination or co-extrusion processes.
Solution Approach 2:
Different optically effective substances are distributed in the first and second transparent layers, creating local optical properties that differ between the two sides of the device. This ensures that each side presents a unique visual appearance, preventing counterfeiting while the overall structure remains relatively simple.
2Reliability
If both sides of the security device exhibit the same secure visual effect, then the device is easy to manufacture with a single layer, but it becomes easier to counterfeit
Solution Approach 1:
The device is designed with asymmetric optical properties: the first transparent layer contains optically effective substances that produce a specific visual effect when viewed from one side, while the second transparent layer contains different optically effective substances producing a different effect when viewed from the opposite side. This asymmetry in optical characteristics significantly enhances anti-counterfeiting capability while the manufacturing process remains straightforward using conventional multi-layer fabrication techniques.
3Reliability
If transparent layers with optically effective substances are added to create different appearances from each side, then security is enhanced, but the device structure becomes more complex
Solution Approach 1:
The optically effective substances are segmented into two separate transparent layers rather than being mixed in a single layer. This segmentation enables each layer to be optimized for specific optical properties visible from opposite sides, enhancing security while the overall structure remains manageable through standard multi-layer manufacturing processes such as lamination or co-extrusion.
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 device presents two different yet precisely registered secure visual effects from each side, significantly enhancing security by making it difficult to counterfeit, as the appearance changes based on the viewing side due to the interaction of the optically effective substances in the transparent layers.
Implementation Method 1
optically variable effect generating relief structure such as holograms and diffraction gratings
Implementation Method 2
a reflection enhancing layer extending over the relief structure and following the contour of the relief
Implementation Method 3
the first and/or second transparent layer comprises one or more optically effective substances such that the appearance of the optically variable effect generated by the relief structure is different when viewed through the first transparent layer compared with when viewed through the second transparent layer
Data Source
AI summary
A security device is provided, including a first transparent layer having an optically variable effect generating relief structure formed in a surface thereof; a reflection enhancing layer extending over the relief structure and following the contour of the relief; and a second transparent layer extending over the reflection enhancing layer, the lateral extent of the second transparent layer being less than the whole area of the security device and corresponding to the lateral extent of the reflection enhancing layer. The first and/or second transparent layer includes one or more optically effective substances such that the appearance of the optically variable effect generated by the relief structure is different when viewed through the first transparent layer compared with when viewed through the second transparent layer, at least under illumination at a wavelength at which at least one of the optically effective substance(s) is visible.