Spin-Resonance Sensor Core Using Eddy-Current Damping Materials
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Solution Overview
Problem
Existing authenticity testing methods for data carriers with spin-resonance features, such as banknotes, face challenges in reliably verifying the authenticity of rapidly moving items due to induced vertebral flows that lead to signal loss and measurement inaccuracies.
Innovation Solution
A sensor element with a magnetic core made from vertebral current-damping materials, such as ferrites or soft-magnetic powder, combined with a permanent magnet and modulation coil, is used to generate a static and varying magnetic field, reducing vertebral flows and enhancing signal integrity for spin-resonance testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional magnetic cores are used for spin-resonance testing, then the testing method can be implemented, but vertebral flows are induced causing signal loss and measurement inaccuracies
Solution Approach 1:
The patent changes the electrical conductivity parameter of the magnetic core material from conventional high-conductivity materials to eddy current damping materials with specifically reduced electrical conductivity. This parameter change suppresses vertebral flows while maintaining sufficient magnetic permeability for spin-resonance testing, thereby improving both authentication reliability and measurement precision simultaneously
Solution Approach 2:
The patent employs composite magnetic core structures combining ferrite particles or powder with binding agents to create materials with optimized magnetic properties. These composite materials achieve the right balance between magnetic permeability (needed for spin-resonance) and electrical conductivity (needed to suppress vertebral flows), resolving the contradiction between reliable authentication and precise measurement
2Productivity
If high-frequency measurements are performed on rapidly moving data carriers, then productivity increases, but vertebral flows increase causing signal loss
Solution Approach 1:
The patent converts the harmful effect of time-varying magnetic fields (which induce vertebral flows and signal loss) into a beneficial outcome by using eddy current damping materials. These materials intentionally induce controlled eddy currents that create opposing magnetic fields to cancel out the harmful vertebral flows, allowing high-frequency measurements on rapidly moving data carriers without signal loss, thus achieving both high productivity and signal integrity
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 design allows for precise and reliable authenticity checks of rapidly moving data carriers by minimizing vertebral flows, improving signal-to-noise ratio, and enabling high-frequency measurements, resulting in more accurate and reproducible results.
Implementation Method 1
The magnetic core of the sensor element is at least partially formed from an eddy current damping magnetic material
Implementation Method 2
a resonator for exciting the spin resonance feature of the data carrier to be tested and for recording the signal response of the spin resonance feature
Implementation Method 3
an element for generating a static magnetic flux in the air gap, a modulation coil for generating a time-varying magnetic field in the air gap
Data Source
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AI summary
The invention relates to a sensor element (30) for authenticating a flat data carrier (10), in particular a bank note, that has a spin resonance feature (12). The sensor element (30) contains a magnetic core (44) having an air gap (46) into which the flat data carrier (10) can be inserted for authentication, an element (40) for generating a static magnetic flux in the air gap (46), a modulation coil (36) for generating a time-variable magnetic field in the air gap (46), and a resonator (32) for exciting the spin resonance feature (12) of the data carrier (10) to be authenticated and for recording the signal response from the spin resonance feature (12). The magnetic core (44) of the sensor element (30) is formed at least in part from an eddy-current-damping magnetic material (62, 64, 72). The invention also relates to a test device having such a sensor element (30).