Integrated Security Substrate with Colour Shifting Element
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Solution Overview
Problem
The manufacturing process of security sheets is inefficient due to the time-consuming production of separate security devices that are then incorporated into substrates, and these devices are vulnerable to damage or tampering when adhered to the sheets.
Innovation Solution
A method of forming a polymer substrate with a colour shifting element and surface relief integrated within, where the security device is formed simultaneously with the substrate, reducing the need for separate security devices and enhancing durability by embedding it within the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate security devices are manufactured and then incorporated onto security sheets, then the security device can be produced with specific optical effects, but the manufacturing process becomes time-consuming and inefficient
Solution Approach 1:
The patent combines the security device manufacturing process with the substrate manufacturing process into a single integrated operation. The colour shifting element is formed within the polymer substrate during the extrusion process itself, eliminating the need for separate device production and subsequent incorporation steps. This merging of processes directly resolves the contradiction by maintaining security device quality while dramatically improving manufacturing efficiency.
Solution Approach 2:
The colour shifting element is formed within the substrate during the extrusion process before the substrate is completed. By performing the security device formation as a preliminary action during substrate manufacturing, the patent eliminates subsequent time-consuming incorporation steps while ensuring the security device is already integrated and functional in the final product.
2Reliability
If security devices are adhered to the outer layer of security sheets, then the security device can be incorporated into the sheet, but the device becomes vulnerable to damage or tampering
Solution Approach 1:
The colour shifting element is nested within the polymer substrate structure, embedded inside rather than adhered to the surface. This nesting approach protects the security device from external damage and tampering while maintaining its optical functions, directly resolving the contradiction between incorporation and durability.
Solution Approach 2:
The security device and substrate are merged into a single integrated structure where the colour shifting element becomes an intrinsic part of the polymer substrate. This merging eliminates the vulnerability associated with adhered devices while ensuring secure incorporation, as the device cannot be separated or damaged independently from the substrate.
3Reliability
If multiple separate manufacturing steps are used for security devices and substrates, then each component can be optimized independently, but the overall process becomes complex and time-consuming
Solution Approach 1:
The patent merges the security device formation process with the substrate extrusion process into a single simultaneous operation. The colour shifting element is formed within the polymer material during extrusion itself, eliminating multiple separate manufacturing steps and significantly reducing manufacturing cycle time while maintaining the ability to optimize both components through controlled formulation and processing parameters.
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 significantly reduces manufacturing time, enhances security by integrating the device within the substrate, making it less prone to damage, and allows for efficient production of personalized security sheets with unique optical effects.
Implementation Method 1
Such a colour shifting element generates a coloured appearance which changes dependent on the viewing angle. Examples of known colour shifting structures include photonic crystals, liquid crystals, interference pigments, pearlescent pigments, structured interference materials or thin film interference structures including Bragg stacks.
Implementation Method 2
the surface relief modifies the angle of light incident to, and reflected from, the colour shifting element so as to provide a different optical effect to the viewer
Data Source
Figure 1a~2b
Figure 3
Figure 4~7
AI summary
A method of forming a polymer substrate for a security sheet is provided. The method comprises: providing first and second overlapping polymer layers each providing outwardly facing surfaces, and a colour shifting element positioned between the first and second polymer layers adapted to provide a first optical effect to a viewer, wherein the first polymer layer comprises a region substantially transparent to visible light such that the colour shifting element is viewable through the first polymer layer, and; joining together the first and second polymer layers in order to generate a polymer substrate wherein, during the joining step, a surface relief is formed in the outwardly facing surface of the first layer, the surface relief being adapted to interact with light from the colour shifting element in order to modify the first optical effect to provide a second optical effect different from the first optical effect.