Security Device Light Control Layer Colour Shifting
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Solution Overview
Problem
Existing security devices with colour shifting elements face challenges in producing multiple colour shifting effects due to the difficulty in creating surface reliefs with varying facet angles, making them susceptible to counterfeiting.
Innovation Solution
Incorporating a light control layer with both functional and non-functional regions over a colour shifting element, where the non-functional regions are imperceptible to the naked eye, allowing for a combined optical effect by mixing colours from functional regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surface relief with multiple different facet angles is used to produce multiple colour shifting effects, then the security against counterfeiting is improved, but the manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The light control layer is segmented into multiple distinct layers, where each layer contains surface reliefs with specific facet angles. This segmentation allows each layer to be manufactured separately with controlled facet angles, and when stacked, the layers collectively produce multiple colour shifting effects. This resolves the manufacturing difficulty by breaking down the complex multi-angle surface relief into simpler, separable layers that can be produced more easily and then assembled.
2Adaptability or versatility
If a light control layer with multiple facet angles is implemented, then multiple colour shifting effects are achieved, but the device complexity increases
Solution Approach 1:
Instead of varying facet angles within a single two-dimensional surface relief layer, the invention transitions to a three-dimensional stacked layer structure. Each layer in the stack has surface reliefs with different facet angles, and by stacking multiple layers, the system achieves multiple colour shifting effects. This dimensional transition from a single-layer to multi-layer structure simplifies the complexity of each individual layer while achieving the desired versatility through layer combination.
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 enables easier control of light modification, resulting in a single security device that exhibits an array of colours, enhancing security by making it difficult to counterfeit and easy to authenticate.
Implementation Method 1
the surface relief comprises a plurality of angled facets that refract the light incident to, and reflected from, the colour shifting element
Implementation Method 2
a colour shifting element to produce an optically variable effect... generates a coloured appearance which changes dependent on the viewing angle
Data Source
Figure 1a~1b
Figure 2~5
Figure 6~12
AI summary
A method of forming a security device comprising a colour shifting element, wherein the colour shifting element provides a first optical effect, the method comprising; providing a light control layer over at least a part of the colour shifting element, the light control layer comprising a functional region and at least one non-functional region, wherein the functional region comprises a surface relief adapted to modify the angle of light from the colour shifting element so as to generate a second optical effect different from the first optical effect, and wherein the non-functional region does not substantially modify the angle of light from the colour shifting element, and; wherein the at least one non-functional region is not discernible to the naked eye.