Metallized Relief Security Element Demetallization
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Solution Overview
Problem
Existing methods for producing security elements with fine demetallized areas in metalized relief structures are limited by resolution and require significant time and expense, particularly for achieving precise alignment and narrow demetallized features.
Innovation Solution
A method involving a carrier with relief and flat areas, where a thin wash-ink layer is applied and metallized, followed by a solvent wash-out step that removes metallization in the flat areas while preserving it in the relief areas, allowing for precise demetallization and alignment with the underlying structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a washing process with high-pigment ink is used to create demetallized areas, then the production of demetallized areas is achieved, but the resolution is limited to about 100 to 200 μm line thickness
Solution Approach 1:
The patent applies different treatments to different areas of the substrate: the relief areas receive a first wash ink layer that is removed after metallization, while the flat areas receive a second wash ink layer with different solubility characteristics. This local differentiation enables precise control over where demetallization occurs, achieving narrow demetallized strips with high resolution while maintaining manufacturing feasibility through area-specific process optimization
2Manufacturing precision
If laser demetallization is used to produce finer structures, then higher resolution is achieved, but considerable additional time and expense are involved
Solution Approach 1:
The patent applies wash ink layers to the substrate before metallization occurs. The first wash ink layer is applied to relief areas and the second wash ink layer to flat areas, both before the metallization step. This preliminary positioning of demetallization patterns allows the metallization process itself to define the final structure boundaries, eliminating the need for subsequent laser demetallization and significantly reducing production time while achieving fine structure resolution
3Manufacturing precision
If conventional area-by-area printing of wash ink is used, then demetallization areas can be created, but positional tolerance of approximately 300 μm results
Solution Approach 1:
The patent combines the application of first and second wash ink layers with the relief structure formation process. The wash ink layers are applied in the same printing operation that creates the relief structure, using the relief features themselves as alignment references. This merging of operations eliminates the need for separate printing steps and achieves register accuracy of less than 10 μm by using the relief structure as a self-aligning template
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
Enables the production of filigree demetallized areas with high accuracy and precision, achieving register accuracy of less than 10 μm, which is not possible with conventional methods, and allows for the creation of security elements with narrow demetallized strips between metalized relief areas.
Implementation Method 1
the metallized substrate is subjected to a washing step with a solvent in which the wash paint is removed together with the overlying metallization in the flat area
Data Source
Figure 1~3
Figure 4(a)~4(d)
AI summary
The invention relates to a method for manufacturing a security element with a metallized relief area (22, 24) and a corresponding narrow, demetallized flat area (28), wherein R) a carrier (40, 42) is provided with a relief structure (14) with raised areas and depressions (30) such that a relief area (32, 34) and a corresponding narrow flat area (38) without raised areas and depressions are formed, the flat area (38) separating at least two sub-areas (32, 34) of the relief area from each other, W) a thin layer of wash paint (46, 48) is provided and applied to the carrier (40, 42) in the relief area (32, 34) and in the flat area (38), M) the carrier (40, 42) provided with wash paint (44, 46, 48) at least in the relief area (32, 34) and flat area (38) is metallized, and A) the metallized support (40, 42, 50) is subjected to a washing step with a solvent,in which the wash color (48) is removed together with the overlying metallization (50) in the flat area (38) and the flat area (38) is thereby demetallized, while the metallization (50) remains on the substrate (40, 42) in the relief area (32, 34) and forms the metallized relief area (22, 24).