Security Element with Inclined Relief Lines for Moiré Anti-Counterfeiting
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Solution Overview
Problem
Current security elements for value documents, such as banknotes, struggle to provide a complex and difficult-to-replicate visual effect that is both visible to the naked eye and discernible under microscopic examination, making them vulnerable to counterfeiting.
Innovation Solution
A security element featuring a network of colored bands with gradual shape variations and periodic inclinations, creating a moiré effect that changes with the viewing angle, combined with intaglio printing techniques to enhance the relief and optical complexity, making it challenging for counterfeiters to reproduce.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a simple network of parallel lines in relief with a colored network is used, then the security element is easily identifiable by the public during simple attentive observation, but the visual effect is not sufficiently complex and spectacular
Solution Approach 1:
The patent applies parameter changes by systematically varying the inclination angles of line profiles along their length. Specifically, the angle of inclination changes progressively from one end to the other, creating graduated variations that produce spectacular moiré effects. This transforms simple parallel lines into complex optical patterns without adding multiple layers or colors, resolving the contradiction between simplicity and visual complexity.
Solution Approach 2:
The patent introduces curvature and non-linearity into the previously straight parallel lines by applying gradual inclination changes along the line profiles. This creates curved or undulating line paths that generate complex moiré interference patterns when viewed, transforming simple linear structures into optically complex patterns that are spectacular to the naked eye.
2Device complexity
If non-parallel gratings are used to produce a spectacular moiré effect, then the visual effect is amplified, but the structure becomes more complex and difficult to manufacture
Solution Approach 1:
Instead of using fundamentally non-parallel gratings which would be difficult to manufacture, the patent achieves spectacular moiré effects by changing the inclination angle parameter along the length of otherwise parallel lines. This gradual parameter variation can be implemented using standard printing and embossing techniques, maintaining manufacturing ease while achieving the desired optical complexity.
Solution Approach 2:
The patent employs periodic variations in line inclination angles at controlled intervals along the parallel lines. This periodic modulation of the angle parameter creates regular moiré interference patterns that are spectacular and easy to manufacture, as the periodic structure can be replicated using conventional printing screens and embossing rollers.
3Illumination intensity
If the width of threads is increased to make colors distinguishable with the naked eye, then color visibility improves, but the moiré effect and optical complexity are reduced
Solution Approach 1:
The patent compensates for the reduced color visibility (due to narrower threads) by dramatically increasing the optical complexity through inclination angle variations. The gradual changes in line angles create strong moiré effects that dominate the visual appearance, making the security element spectacular despite the threads being too narrow for easy color distinction with the naked eye.
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 solution produces an amplified optical effect visible to the naked eye while revealing a complex structure under microscopic examination, effectively enhancing both first and second-level security features, making counterfeit banknotes detectable.
Implementation Method 1
a security element giving a moiré effect... moiré is a visual phenomenon of interference resulting, for example, from the superposition of two networks of non-parallel lines... an amplified optical effect is produced compared to that described above, and this with the naked eye
Implementation Method 2
said profiles comprise at least one flank each defining an angle of inclination with respect to a direction normal to the network, said variation in shape comprising a variation of the angle of inclination of the flank of at least one line or of at least two lines of the grating, gradually along this line, respectively from one line to the other, so as to form, in light reflection, a degraded optical effect changing as a function of an angle of observation
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
The present invention relates, in particular, to a security element (12) for a value document (1), which consists of an initially planar substrate (G), including an array (14) of raised lines (16), each raised line (16) comprising a profile (F), said profile (F) comprising gradual variations in the shape thereof along a predetermined line (16) or from one line to the other, said array (16) being colored, characterized in that said colored network (16) consists of repeating contiguous strips (3) formed by adjacent or contiguous threads (120, 121, 122) of at least two different colors (B, R, Y), said strips (3) being overall oriented in the same direction as that of said lines (16) of said array (14).