Electroluminescent Security Feature Detection via UV-Induced Conductivity
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Solution Overview
Problem
Existing security features with electroluminescent properties require high excitation voltages for reliable detection, which can lead to operational unreliability due to voltage breakdown and are affected by aging processes, making it challenging to maintain signal strength over the life cycle of security documents.
Innovation Solution
A method involving a combination of electroluminescent substances and substances with conductivity that can be increased by high-energy irradiation, such as UV radiation, to enhance the local excitation field and increase electroluminescence intensity without raising excitation voltages, using a mixture of powdered electroluminophores and optically variable effect pigments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high excitation voltages are used to ensure reliable detection of electroluminescent security features, then detection reliability is improved, but operational unreliability increases due to voltage breakdown
Solution Approach 1:
The security feature is irradiated with UV radiation before detection to preliminarily increase the conductivity of the field-displacement elements. This preliminary action modifies the electrical properties of the material in advance, enabling subsequent detection at lower excitation voltages that do not cause breakdown, thus resolving the contradiction between detection reliability and operational unreliability
Solution Approach 2:
The electrical conductivity of the field-displacement elements is changed from a low initial state to a high conductive state through UV irradiation. This parameter change allows the system to operate at lower voltages while maintaining detection reliability, eliminating the harmful effect of voltage breakdown
2Illumination intensity
If high excitation voltages are applied to maintain signal strength, then electroluminescence intensity is improved, but energy consumption increases and operational reliability decreases
Solution Approach 1:
UV irradiation is applied beforehand to convert field-displacement elements into a high-conductivity state, preliminarily preparing the material to enhance local electric fields. This allows subsequent electroluminescence excitation to achieve high intensity signals with lower energy input, resolving the contradiction between signal strength and energy consumption
Solution Approach 2:
UV radiation acts as an intermediary that modifies the electrical properties of field-displacement elements, which then mediate the enhancement of local electric fields during electroluminescence excitation. This intermediary process enables high signal intensity with reduced direct energy input to the electroluminescent material
3Illumination intensity
If field-displacement elements are used to enhance local electric fields, then electroluminescence intensity is improved, but excitation voltage requirements increase due to material arrangement
Solution Approach 1:
The conductivity parameter of field-displacement elements is dynamically changed from low to high through UV irradiation. This parameter change compensates for the unfavorable material arrangement, enabling effective field enhancement without requiring excessively high excitation voltages, thus resolving the contradiction between signal intensity and device complexity
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 allows for reliable identification of security elements with lower excitation voltages and increased signal strength, maintaining operational reliability throughout the life cycle of security documents, while reducing the risk of voltage breakdown and enhancing energy efficiency.
Implementation Method 1
the security feature comprises at least one first substance with electroluminescent properties and at least one further substance, wherein the electrical conductivity of the further substance is modifiable by UV irradiation
Implementation Method 2
the electrical conductivity of the further substance is modifiable by UV irradiation
Data Source
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AI summary
The invention relates to a device and a method for identifying at least one security element of at least one security feature (2) of a security product, wherein: the security feature (2) comprises a first substance and at least one additional substance; the first substance is an electroluminescent substance; the additional substance is a substance with an electrical conductivity which can be varied by irradiation; the at least one security feature (2) is irradiated; an alternating electrical field is applied to the security feature (2); electroluminescent radiation emitted by the first substance is detected; and the first substance and/or the additional substance is identified depending on at least one property of the electroluminescent radiation.