Lanthanide Complexes for Secure Optical Product Marking
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Solution Overview
Problem
Existing optical markers for product authentication and security are not sufficiently secure due to ease of reproduction and instability, and they often require complex synthesis and multiple excitation wavelengths, which limits their practicality and effectiveness.
Innovation Solution
The use of lanthanide complexes with specific chemical formulations that can be excited by a single wavelength, emitting distinct optical signals in the UV, visible, or NIR ranges, offering high photoluminescence quantum yields and stability, and allowing for customizable and complex optical codes through mixtures of lanthanide ions and ligands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic fluorophores are used to create multicolor optical codes, then multiple color emissions can be achieved, but multiple different organic molecules are required which cannot be excited at the same wavelength and are unstable to photochemical bleaching
Solution Approach 1:
The patent changes the fundamental parameter of the luminescent material from organic fluorophores to inorganic lanthanide complexes. This parameter change enables single-wavelength excitation (typically UV) for multiple emitters and provides exceptional photostability, resolving both the ease of manufacture and reliability issues simultaneously.
Solution Approach 2:
The patent uses composite materials by combining lanthanide ions with organic ligands to form lanthanide complexes. The organic ligand acts as an antenna that absorbs UV light and transfers energy to the lanthanide ions, enabling efficient excitation and emission while maintaining stability.
2Stability of the object's composition
If lanthanides are incorporated into mineral matrices without antenna effect, then structural stability is achieved, but excitation requires high energy laser sources due to very low absorption coefficient
Solution Approach 1:
The patent introduces an intermediary substance - an organic ligand with high UV absorption coefficient - that acts as an energy mediator. The ligand absorbs UV photons and transfers the energy to the lanthanide ions through the antenna effect, enabling excitation at lower energies while maintaining the structural stability provided by the mineral matrix.
3Reliability
If optical markers with complex emission spectra are used for security authentication, then security level is improved, but detection requires specialized measuring devices such as fluorimeters or spectrophotometers
Solution Approach 1:
The patent utilizes the characteristic color emissions of different lanthanide ions (e.g., red for Eu3+, green for Tb3+, yellow for Sm3+) to create security markers. These distinct color signatures provide high security authentication while being detectable by relatively simple color detection devices, reducing the complexity of required measurement equipment.
4Adaptability or versatility
If multiple organic molecules are combined to obtain multicolor optical code, then color diversity is achieved, but the compounds are not identifiable at the same excitation wavelength and have poor discrimination with intrinsic chromophoric components
Solution Approach 1:
The patent changes the emitter type from organic molecules to inorganic lanthanide ions, which have sharp, well-defined emission lines at specific wavelengths. This parameter change provides excellent spectral discrimination and allows all lanthanide emitters to be excited at the same wavelength (UV), enabling precise identification and measurement of each component's contribution to the overall optical code.
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 lanthanide complexes provide a secure, stable, and easily synthesizable means for creating complex optical codes that are difficult to reproduce, with high detection sensitivity and specificity, suitable for various authentication and security applications.
Implementation Method 1
Each color code is obtained by adjusting the quantity of lanthanide complexes used and/or by adjusting the excitation wavelength. The lanthanide complexes are chosen from compounds of formula I... Each lanthanide complex can be excited by irradiation at a single length d wave and emit different optical signals
Implementation Method 2
In order to excite the emission of the metal with lower energies, it is necessary to sensitize the emission of the lanthanide ion by complexation with a suitable organic chromophore capable of absorbing the photons and transferring them efficiently to the lanthanide ions (antenna effect)
Data Source
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AI summary
The present invention relates to the use of at least one lanthanide complex for the optical marking of products, compositions for the optical marking of products, an optical marking process comprising a step of applying these compositions, and lanthanide complexes used in these compositions.