Multi-Tone Security Image via Opacifying Layer Gaps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Polymer document substrates lack integral security features due to their non-fibrous construction, limiting the incorporation of conventional watermarking techniques, and thus require additional security elements applied post-manufacturing.
Innovation Solution
A security print medium with opacifying layers that create a multi-tone image when viewed in reflection and a different image when viewed in transmission, achieved by strategically placing gaps in the opacifying layers to vary optical density, allowing for an integral security feature similar to watermarks in fibrous substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional watermarking techniques are used, then integral security features are achieved in fibrous substrates, but these techniques are not available for polymer substrates due to their non-fibrous construction
Solution Approach 1:
The invention changes the fundamental parameter of how security features are created - transitioning from fibre density variation (paper) to opacifying layer gap patterns (polymer). Multiple opacifying layers are applied with specific gap patterns that align to create multi-tone images in transmission light, adapting the watermarking concept to polymer substrate characteristics.
Solution Approach 2:
The invention uses composite construction by applying multiple opacifying layers over a polymer substrate. Each layer contains gaps in specific patterns, and the combination of layers creates the security feature. This composite approach enables integral security features in polymer substrates by combining the substrate material with functional opacifying layers.
2Reliability
If security elements are applied after substrate manufacturing, then polymer substrates can have security features, but these features are not integral to the substrate
Solution Approach 1:
The opacifying layers are applied to the polymer substrate during the manufacturing process, before the substrate is cut or further processed into final documents. This preliminary application ensures the security features are built into the substrate structure itself, making them integral and inseparable from the substrate.
Solution Approach 2:
The invention merges the security feature creation process with the substrate manufacturing process. The opacifying layers are applied and integrated into the substrate structure, combining the substrate formation and security feature creation into a single unified process, making the security features integral to the substrate.
3Reliability
If multiple opacifying layers are applied to create multi-tone images, then security is enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The security feature is segmented into multiple opacifying layers, each contributing a portion of the final multi-tone image. Each layer contains gaps in specific patterns, and the segmentation allows the complex security feature to be built up incrementally through layer application, rather than requiring a single complex process.
Solution Approach 2:
The invention adds the dimensional aspect of multiple layers stacked in the z-direction to create multi-tone images. By utilizing the layering dimension, the patent achieves complex security features through the vertical stacking and optical interaction of multiple opacifying layers, each with its own gap pattern.
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
Enhances the security of polymer document substrates by providing a built-in, multi-tone image that changes appearance with lighting conditions, offering a robust and secure visual effect without compromising the document's integrity.
Implementation Method 1
the primary function of the opacifying layers (which are typically formed of a polymeric, non-fibrous, light-scattering material) is to render the majority of the document non-transparent
Implementation Method 2
the cumulative effect of which is a variation in the optical density of the security print media across the region of the substrate, depending on the number of opacifying layers present at each point
Implementation Method 3
when held up to the light so as to be viewed in transmission, provides that a different multi-tone image is revealed in the region of the multi-tone first image
Data Source
Figure 1(a)~1(b)
Figure 1(c)~1(d)
Figure 2(a)~3(c)
AI summary
A security print medium is disclosed for forming security documents therefrom. The security print medium comprises a transparent or translucent polymer substrate having first and second opposing surfaces, and a plurality of overlapping opacifying layers disposed on the first and/or second surfaces of the polymer substrate, each of the opacifying layers being a layer of semi-opaque material. In a first region of the substrate a multi-tonal first image is exhibited by the plurality of overlapping opacifying layers in combination with one another, each of the plurality of overlapping opacifying layers having gap(s) in which the semi-opaque material of the layer is absent, the gap(s) of each layer being defined in accordance with a different respective sub-image, the sub-images in combination defining the multi-tonal first image. The number of opacifying layers overlapping one another at any one location varies across the substrate, the resulting variation in optical density of the plurality of overlapping opacifying layers in combination with one another giving rise to the multiple tones of the multi-tonal first image. The security print medium further comprises a print of a multi-tonal second image, different from the first image, on the first and/or second surfaces of the polymer substrate in a second region and covered from the point of view of an observer on a first side of the security print medium by the plurality of opacifying layers exhibiting the multi-tonal first image. The first and second regions at least partially overlap. When the security print medium is viewed by the observer in reflected light, the first image dominates the appearance of the overlapping area(s) of the first and second regions and when the security print medium is viewed by the observer in transmitted light, the second image dominates the appearance of the overlapping area(s) of the first and second regions.