Chiral Liquid Crystal Marking via Modifying Resin Shift
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Solution Overview
Problem
Existing methods for enhancing the security of chiral liquid crystal polymer films are inadequate in providing a selective and controlled manner to modify the chiral liquid crystal layer, leading to difficulties in creating a strong and reliable marking that is hard to reproduce, and they are not compatible with high-speed industrial processes for large volumes of items such as pharmaceuticals and cigarettes.
Innovation Solution
A salt-free chiral liquid crystal precursor composition containing specific nematic and chiral dopant compounds, combined with a modifying resin having ether functionalities, is applied to a substrate, allowing for the controlled shifting of the selective reflection band and enhanced color contrast, enabling the creation of a secure marking that is difficult to counterfeit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a chiral liquid crystal precursor composition is applied to create a security marking, then the marking provides visual recognizability and security features, but the marking can be easily reproduced and tampered with by counterfeiters
Solution Approach 1:
The patent applies local quality by introducing a modifying resin that creates localized regions with different optical properties. The modifying resin is applied to specific areas of the substrate, creating zones where the selective reflection band is shifted to different wavelengths. This results in a non-uniform pattern that cannot be easily replicated, as counterfeiters would need to reproduce both the base marking and the precise modifying resin pattern to achieve the same optical effect.
Solution Approach 2:
The patent utilizes parameter changes by modifying the optical properties of the liquid crystal composition through the adding of modifying resin. The modifying resin changes the position of the selective reflection band exhibited by the cured chiral liquid crystal precursor composition, creating regions with different reflection wavelengths. This parameter change (wavelength shift) creates a complex, multi-wavelength pattern that enhances security and prevents easy counterfeiting.
2Reliability
If existing methods are used to modify the chiral liquid crystal layer, then some security enhancement is achieved, but the process is not compatible with high-speed industrial production
Solution Approach 1:
The patent applies preliminary action by pre-formulating the modifying resin with specific ether functionalities that are designed to interact with the chiral liquid crystal precursor composition. The modifying resin is prepared in advance with the appropriate chemical structure (ether functionalities) that enables it to shift the selective reflection band when contacted with the liquid crystal composition. This pre-prepared modifying resin can be quickly applied and cured in industrial processes, maintaining high production speeds while achieving security enhancement.
3Reliability
If a modifying resin is used to shift the selective reflection band, then color contrast and security are improved, but the process complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a modifying resin as a mediating substance between the substrate and the final security marking. The modifying resin serves as an intermediary layer that interacts with the chiral liquid crystal precursor composition to produce the desired optical effect (shifting the selective reflection band). This intermediary approach simplifies the overall process compared to attempting to directly create complex multi-wavelength patterns, as the modifying resin automatically produces the wavelength shift through its chemical interaction with the liquid crystal composition.
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 solution effectively enhances the security of the marking by shifting the selective reflection band, improving color contrast, and increasing production efficiency, making it suitable for high-volume industrial applications such as pharmaceuticals and cigarettes.
Implementation Method 1
When illuminated with white light, the cholesteric liquid crystal structure reflects light of a certain color which depends on the material in question and generally varies with the viewing angle and the temperature. The observed color is the result of a physical reflection effect at the cholesteric helical structure
Implementation Method 2
Nematic liquid crystals without chiral dopant show a molecular arrangement that is characterized by its birefringence
Implementation Method 3
The ordered liquid crystalline state depends upon the presence of a chiral dopant. Nematic liquid crystals without chiral dopant show a molecular arrangement that is characterized by its birefringence
Data Source
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AI summary
Disclosed is a substrate which has thereon a marking or layer comprising a salt-free cured chiral liquid crystal precursor composition which comprises one or more nematic compounds A and one or more chiral dopant compounds B which are capable of giving rise to a cholesteric state of the chiral liquid crystal precursor composition and are of formula (I) as set forth herein. A modifying resin made from one or more polymerizable monomers comprising an average of at least one ether functionality per polymerizable group is disposed between the substrate and the marking or layer and in contact with the marking or layer in one or more areas thereof. The modifying resin changes the position of a selective reflection band exhibited by the cured chiral liquid crystal precursor composition on the substrate in the one or more areas.