Polymer Layer Opacity Matching for Luminescent Security Imprints
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Solution Overview
Problem
Security elements with luminescent imprints under UV radiation suffer from opacity differences that impair forgery protection by making boundary contours easily recognizable, compromising authenticity and security.
Innovation Solution
Adapting the opacity of at least one polymer layer to match the opacity of the luminescent halftone printed image's boundary contour, particularly using a diffusely scattering matte lacquer layer and a translucent adhesive layer, to conceal the boundary contour under white light while maintaining visibility under UV irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a luminescent imprint is applied between polymer layers, then the security feature is visually recognizable under UV radiation, but the boundary contour becomes strongly recognizable under white light due to opacity differences
Solution Approach 1:
The patent applies a locally adapted opacity to the polymer layers specifically in the region of the boundary contour of the imprint area. This local modification ensures that the polymer layer's opacity matches the imprint's opacity at the boundaries, eliminating the harmful contrast that would otherwise make the boundary contour strongly recognizable under white light, while preserving the luminescent security feature's visibility under UV radiation.
Solution Approach 2:
The patent modifies the opacity parameter of the polymer layers in the boundary contour region to match the imprint's opacity. By changing this physical parameter locally, the harmful visual contrast is eliminated, preventing the boundary contour from being strongly recognizable under white light, while the luminescent properties remain intact for UV detection.
2Object-generated harmful factors
If the opacity of polymer layers is adapted to the imprint area, then the boundary contour visual recognizability is diminished, but the production complexity increases
Solution Approach 1:
The opacity adaptation is applied locally only in the region of the boundary contour of the imprint area, not across the entire polymer layer. This localized approach minimizes the additional production complexity by limiting the modified region to where it is most needed, rather than requiring complex full-layer opacity control.
Solution Approach 2:
The patent applies opacity adaptation partially, specifically targeting the boundary contour region where it is most critical for reducing visual recognizability. This partial action approach balances the need for security feature concealment with production feasibility, avoiding the excessive complexity that would result from applying opacity control to the entire polymer layer.
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
This approach enhances forgery protection by making the security feature less noticeable under normal conditions, thereby improving authenticity verification and reducing the risk of forgery, while maintaining a stable and cost-effective production process.
Implementation Method 1
a printing ink can be used which contains luminescent colorants or pigments. Such a luminescent colorant and/or luminescent pigment can be brought into an energetically excited state, for example, under the effect of radiation, and can then pass spontaneously into a state of lower energy, wherein photons of a specific wavelength are emitted, which is perceivable by the human eye in the case of a corresponding wavelength.
Implementation Method 2
a printing ink can be used which contains luminescent colorants or pigments. Such a luminescent colorant and/or luminescent pigment can be brought into an energetically excited state, for example, under the effect of radiation
Implementation Method 3
If at least one of the two polymer layers has an opacity in the region of the boundary contour of the imprint area
Data Source
AI summary
A security element and a value document having such a security element in the form of a strip having a first and second polymer layer are shown, having a visually recognizable halftone printed image, which is luminescent under UV radiation, between the first and second layer, wherein the halftone printed image has an opacity and forms at least one imprint area having a boundary contour within the security element. To increase the forgery protection, it is proposed that at least one of the two polymer layers have an opacity at least in the region of the boundary contour of the imprint area and be adapted in its opacity to the opacity of the imprint area, in order to diminish the visual recognizability of the boundary contour of the imprint area of the luminescent halftone printed image on the security element.