Optically Variable Security Element with Dual Relief Structures
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Solution Overview
Problem
Existing foil-based security elements for data carriers, such as banknotes, often obscure the window area with large-scale metallization, reducing its recognizability and effectiveness in verifying authenticity.
Innovation Solution
A data carrier with a transparent window region and a substantially opaque region, featuring an optically variable security element with a partially translucent and partially light-reflecting transmission region and a substantially opaque, light-reflecting reflection region. This security element includes two independent, partially overlapping relief structures at different height levels, coated with a semi-transparent reflection-enhancing coating and an opaque reflection layer respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If foil-based security elements with large-scale metallization are used to protect the window area, then security against counterfeiting is improved, but the recognizability of the window area is impaired
Solution Approach 1:
The security element applies different optical properties to different regions: the transmission region uses a semi-transparent coating with optimized reflectance (10-40%) to maintain visibility, while the reflection region uses an opaque reflective coating for maximum security. This local differentiation allows the window area to remain recognizable while providing adequate security protection.
Solution Approach 2:
The patent optimizes the reflectance parameter of the semi-transparent coating to a specific range (10-40%) that balances security and visibility. By controlling the optical parameters of the coating layers, the security element achieves both protective function and visual recognizability of the window area.
2Illumination intensity
If a semi-transparent reflection-enhancing coating is applied to the higher relief structure, then reflection is enhanced without significantly impairing transmission, but manufacturing complexity increases
Solution Approach 1:
The security element divides the coating structure into two independent relief structures at different height levels, each with its own coating characteristics. The higher relief structure receives the semi-transparent reflection-enhancing coating while the lower relief structure receives the opaque reflective coating, allowing independent optimization of each layer's function.
Solution Approach 2:
The patent uses composite coating structures combining semi-transparent dielectric layers with optimized refractive indices. The semi-transparent reflection-enhancing coating comprises multiple layers with carefully selected optical properties to achieve enhanced reflection while maintaining transmission, creating a composite material system that balances both requirements.
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 security element effectively protects the window area without significantly impairing its recognizability, achieving high reflection and transmission at different wavelengths, thus providing enhanced protection against counterfeiting.
Implementation Method 1
The semi-transparent reflection-enhancing coating increases the reflectance of the higher relief structure without significantly impairing the light transmittance of the transmission region
Implementation Method 2
The semi-transparent reflection-enhancing coating contains one or more high-refractive index layers
Implementation Method 3
The lower relief structure is coated with an opaque reflection layer that follows the contours of the relief
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to an optically variable security element (20) for securing valuables, the surface area of which is defined by a z-axis perpendicular to it, with a feature area (22) comprising a partially translucent and partially reflective transmission area (26) and a substantially opaque, reflective reflection area (24). The feature area (22) contains two independent, partially overlapping relief structures (34, 44) arranged at different heights in the z-direction, forming a lower and a higher relief structure. The higher relief structure (34) is provided with a semi-transparent, reflection-enhancing coating (36) that follows the relief contour and contains one or more high-refractive-index layers, while the lower relief structure (44) is provided with an opaque reflective layer (46) that follows the relief contour.In the transmission area (26), at least in some areas the semi-transparent reflection-enhancing coating (36) of the higher relief structure (34) is present, but not the opaque reflection layer of the lower relief structure, while in the reflection area (24) the opaque reflection layer (46) of the lower relief structure (44) and at least in some areas the semi-transparent reflection-enhancing coating (36) of the higher relief structure (34) are present.