Dichroic Dye Liquid Crystal Foil for Dual-Side Security
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Solution Overview
Problem
Current security elements for documents of value, such as banknotes, lack innovative optical effects and efficient methods for large-scale production and combination with other security features, necessitating a solution that provides unique and recognizable optical effects while ensuring high productivity and ease of integration with existing security elements.
Innovation Solution
A method for producing a foil security element using a liquid crystalline mixture with dichroic dyes, involving a lacquer layer and embossing with a circular molding tool to create alignment structures that allow different images to be visible from opposite sides, combined with additional security features like metallized layers and polarizers, enabling the creation of latent images visible under polarized light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional security elements are used, then production is simple and cost-effective, but optical effects are lackluster and not recognizable by the unarmed eye
Solution Approach 1:
The patent combines liquid crystalline material with dichroic dyes to create a composite security element that exhibits extraordinary optical effects. The dichroic dyes are embedded within the liquid crystal matrix, creating a material that displays different colors and images when viewed from different angles or under polarized light, thereby enhancing visibility and recognizability without requiring complex external systems
Solution Approach 2:
The patent utilizes the color-changing properties of dichroic dyes within the liquid crystal structure. These dyes exhibit different absorption characteristics for polarized light depending on their orientation, causing the material to display different colors and images when viewed from different angles or when the liquid crystal orientation changes, providing remarkable optical effects visible to the unarmed eye
2Reliability
If multiple security features are combined, then security verification is enhanced, but production efficiency decreases
Solution Approach 1:
The patent merges multiple security features into a single integrated foil element. The liquid crystalline layer with dichroic dyes is applied directly onto a carrier substrate and cured to form a unified structure that combines optical effects, latent images, and security features in one component, eliminating the need for separate production and assembly steps for multiple security elements
Solution Approach 2:
The liquid crystal foil serves multiple functions simultaneously: it provides extraordinary optical effects for visual verification, contains latent images for authentication, and can be integrated with other security features. This multi-functional design allows a single element to replace multiple separate security components, maintaining high security verification capability while improving production efficiency
3Manufacturing precision
If liquid crystals are oriented using electrical fields with electrodes, then orientation precision is high, but device complexity and production cost increase
Solution Approach 1:
The patent extracts and eliminates the complex electrode structure from the liquid crystal orientation system. Instead of using electrical fields generated by electrodes, the invention employs embossing elements that directly impose mechanical orientation on the liquid crystal molecules through contact embossing, removing the need for electrodes, power supplies, and control circuits while achieving precise orientation
Solution Approach 2:
The patent replaces the electrical field-based orientation mechanism with a mechanical embossing system. Embossing elements with specific surface structures are pressed against the liquid crystal layer, mechanically inducing the desired molecular orientation through direct contact and physical deformation, thereby substituting complex electrical systems with simpler mechanical processes
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 method enables the production of polymerized liquid crystal sheets with multiple latent images on each side, enhancing security features with unique optical effects, improving productivity, and allowing for easy integration with other security elements, thereby enhancing the authenticity verification of documents.
Implementation Method 1
Liquid crystals in their liquid crystalline state may be oriented by outside forces. The orientation may be induced by electric fields, magnetic fields, electrostatic, chemical composition of surfaces and their topography.
Implementation Method 2
A polymerized liquid crystalline layer contains at least one substance, whose orientation depends on the orientation of the molecules of the liquid crystals surrounding it. This substance may be a dye, whose absorption of light depends on its orientation in relation to the orientation of the polarization of the incident light.
Implementation Method 3
performing an embossing of the uncured liquid crystalline mixture to provide a second alignment structure, wherein the second alignment structure shows an image in the cured state
Implementation Method 4
Crosslinking can take place by UV curing.
Data Source
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AI summary
The present invention is directed towards a method for producing a foil security element for securing a document of value by means of a liquid crystalline mixture containing dichroic dyes and is furthermore directed towards the foil security element as such. Furthermore, a document of value is suggested comprising the foil security element along with an apparatus for provision of such a security element and a computer program product.