Security Paper Ink-Receptive Layer Thickness Variation
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Solution Overview
Problem
Existing security papers face challenges in maintaining the visibility of optically variable security elements when additional printing layers are applied, as the visibility can be impaired or completely prevented, and the use of recesses in the printing layer disrupts the visual impression and design freedom.
Innovation Solution
A security paper with an optically variable security element and an ink-accepting layer where the layer thickness is reduced over the area containing the security element, allowing for uniform ink acceptance and visibility of the optically variable effect without disrupting the design or visual impression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an ink-accepting layer with sufficient layer thickness is provided to increase ink acceptance capacity, then ink acceptance capacity is improved, but the optically variable effect of the security element is reduced or completely suppressed
Solution Approach 1:
The ink-accepting layer is designed with spatially varying thickness: a first layer thickness in areas outside the optically variable security element (for sufficient ink acceptance) and a reduced second layer thickness in the area of the security element (for maintaining optical visibility). This local differentiation resolves the contradiction by optimizing both ink acceptance and optical properties in their respective zones.
Solution Approach 2:
The ink-accepting layer is segmented into at least two distinct areas with different thickness characteristics: a first area with greater thickness for ink absorption and a second area with reduced thickness for optical transparency. This segmentation allows each zone to fulfill its specific function without compromising the other.
2Ease of manufacture
If a recess is provided in the printing layer in the area of the optically variable security element to ensure visibility, then the optically variable effect can be recognized, but the freedom of design for the printed image is impaired and a clearly visible edge disrupts the visual impression
Solution Approach 1:
Instead of creating a discrete recess structure, the invention uses local quality variation in the ink-accepting layer thickness. The layer transitions smoothly from greater thickness to reduced thickness, eliminating sharp edges and maintaining design freedom while ensuring optical visibility of the security element.
Solution Approach 2:
The invention changes the thickness parameter of the ink-accepting layer continuously or gradually from the first thickness to the reduced second thickness in the area of the security element. This parameter change eliminates the need for discrete recess structures and their associated visual disruptions.
3Ease of manufacture
If the ink-accepting layer has uniform thickness across the substrate surface, then manufacturing is simplified, but ink acceptance capacity is not optimized for areas with optically variable security elements
Solution Approach 1:
The ink-accepting layer employs local quality differentiation with at least two distinct thickness zones: a first layer thickness in areas without security elements (optimizing ink acceptance) and a reduced second layer thickness in the area of the optically variable security element (maintaining optical visibility). This resolves the contradiction between manufacturing simplicity and functional optimization.
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 application of a printed image over the entire surface while ensuring the visibility of the optically variable security element, simplifying the manufacturing process and enhancing design freedom without visible edges or disruptions.
Implementation Method 1
an optically variable security element, whose visual impression generated by a viewer depends on the viewing direction
Implementation Method 2
the viewer's viewing angle of the optical element and possibly also from the direction of incidence of an illuminating light beam
Implementation Method 3
in a second area of the substrate surface, which describes the area in which the optically variable security element is located or optionally can lie, has a reduced layer thickness compared to the first layer thickness
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a security paper (7) for producing valuable documents, comprising a substrate (8) having an optically variable security element (2), which can be detected when at least a first side of the substrate is observed, and an ink-receiving layer (6), which is arranged at least on the first side of the substrate, wherein the ink-receiving layer has a first layer thickness in a first substrate area lying outside the area of the optically variable security element and a recess or a reduced layer thickness compared to the first layer thickness in a second substrate area (3) in which the optically variable security element is arranged.