Lenticular Security Device Color Switch via Image Strip Segmentation
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Solution Overview
Problem
Conventional security devices, such as those using holograms, thin film interference structures, and lenticular devices, face challenges in distinguishing authenticity due to limited color range and high production costs, and require precise registration, making them difficult to manufacture and verify.
Innovation Solution
A security device featuring an array of lenticular focusing elements and image strips that switch colors when tilted, allowing for a simple and secure verification process without the need for precise registration, using cylindrical lenses or micromirrors over pairs of image strips where one strip defines a first image in one color and the other in a second color, and vice versa, with optional complementary color switching between two lenticular devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional lenticular devices use microprinting with strips of different colours, then angularly dependent colour perception is achieved, but very precise register between microlenses and microprinting is required making manufacture difficult
Solution Approach 1:
The device is segmented into multiple lenticular elements, each independently associated with a pair of image strips. This segmentation allows each element-strip pair to function autonomously, eliminating the need for precise registration across the entire device while maintaining the colour switching effect.
Solution Approach 2:
Instead of requiring precise registration between lenses and strips, the invention inverts the approach by designing the system so that registration precision becomes irrelevant. The colour switching effect is achieved through the inherent optical properties of each lens-strip pair rather than through precise alignment.
2Adaptability or versatility
If thin film interference structures and liquid crystal structures are used to generate angularly dependent coloured reflection, then colour switching effect is achieved, but the range of possible colours is limited by fundamental optical characteristics
Solution Approach 1:
The invention changes the optical parameters by using conventional lenticular structures with printed colour strips instead of relying on the fundamental optical characteristics of thin film interference or liquid crystal helical pitch. This allows for a broader range of colours including non-spectral colours that cannot be achieved with liquid crystals.
Solution Approach 2:
The device combines conventional lenticular optical elements with printed colour patterns, creating a composite structure that leverages the optical focusing properties of lenses with the colour information encoded in printed strips, achieving versatile colour switching without the limitations of single-material optical structures.
3Productivity
If direct laser writing is used to form microimages through microlenses, then exact register between lenses and images is achieved, but the device is not suited to mass production techniques
Solution Approach 1:
The invention uses printed copies of colour information in the form of image strips rather than direct laser writing of unique microimages. This copying approach allows the use of conventional printing techniques suitable for mass production while maintaining the necessary visual fidelity for security applications.
Solution Approach 2:
The invention employs conventional printing methods that are cost-effective and suitable for mass production, replacing expensive and time-consuming direct laser writing processes. The printed colour strips serve as disposable, easily replaceable components that can be manufactured at low cost.
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
The device provides a cost-effective, easy-to-verify security solution with a color switch or opaque/transparent switch between images or backgrounds, enhancing authentication without requiring precise registration, suitable for mass production and various applications.
Implementation Method 1
an array of lenticular focusing elements formed by cylindrical lenses
Implementation Method 2
an array of lenticular focusing elements formed by cylindrical lenses or micromirrors
Implementation Method 3
It is also well known to use thin film interference structures, multilayer polymeric structures and liquid crystal structures to generate angularly dependent coloured reflection
Data Source
Figure 1~2
Figure 3
Figure 4a
AI summary
A security device has a lenticular device comprising an array of lenticular focusing elements (2) located over a corresponding array of pairs of image strips (A,B) such that, in a first viewing direction, a first image strip (A) from each pair is viewed by respective ones of the lenticular focusing elements (2) and, in a second viewing direction, different from the first, a second image strip (B) from each pair is viewed by respective ones of the lenticular focusing elements (2). One (A) of each pair of image strips has portions defining a first image in a first colour and a second image in a second colour respectively, and the other (B) of each pair of image strips has portions defining the first image in the second colour and the second image in the first colour respectively, whereby on tilting the device, a colour switch is observed between the first and second images.