Luminescence Verification Sensor With Velocity-Based Intensity Correction
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Solution Overview
Problem
Existing sensors for verifying luminescence in value documents inaccurately determine luminescence parameters due to corruption from high transport velocities, which is exacerbated by misalignment between illumination and detection areas, leading to inconsistent and inaccurate measurements.
Innovation Solution
A sensor system that corrects luminescence parameters by using a velocity-dependent correction factor, derived from a reference medium, to account for transport velocity, ensuring accurate measurements across different sensors of the same production series.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the value document is transported at high velocity past the sensor for verification, then the productivity of value document processing is improved, but the measurement precision of luminescence parameters deteriorates due to corruption of the temporal intensity curve
Solution Approach 1:
The patent applies parameter changes by introducing a velocity correction factor that modifies the measured luminescence parameter based on the transport velocity. The correction factor is determined as a function of the transport velocity and used to correct the measured luminescence parameter, thereby compensating for the corruption caused by high-speed transport and restoring measurement accuracy while maintaining high processing speeds
Solution Approach 2:
The patent implements feedback by measuring the transport velocity of the value document and using this information to determine an appropriate correction factor. The system continuously monitors the velocity and applies real-time corrections to the luminescence parameters, creating a closed-loop control system that maintains accuracy despite varying transport conditions
2Measurement precision
If the illumination area and detection area are perfectly aligned, then the measurement precision is improved, but the manufacturing precision requirements worsen due to tighter tolerances needed for alignment
Solution Approach 1:
The patent converts the harmful effect of misalignment into a beneficial correction mechanism. Instead of requiring perfect alignment, the system measures the transport velocity and applies a correction factor that compensates for the misalignment effects. This transforms the manufacturing tolerance problem into a measurable and correctable parameter, allowing acceptable alignment while maintaining measurement accuracy through velocity-based correction
3Device complexity
If a single correction factor is used for all sensors of the same production series, then the device complexity is reduced, but the measurement precision may worsen due to sensor-individual variations
Solution Approach 1:
The patent applies universality by developing a velocity correction factor that is applicable to all sensors of the same production series. Instead of requiring individual calibration for each sensor, the correction factor is determined as a function of transport velocity that works universally across the sensor series, reducing complexity while maintaining sufficient accuracy for all sensors in the series
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 system provides consistent and accurate luminescence parameter determination by compensating for velocity-related measurement errors, allowing for precise verification of value documents.
Implementation Method 1
at least one excitation light source (23, 24) for exciting a luminescence of the value document (3) and at least one photodetector (20) for detecting the luminescence of the value document (3) excited by the excitation light source (23, 24)
Implementation Method 2
at least one photodetector (20) for detecting the luminescence of the value document (3) excited by the excitation light source (23, 24)
Data Source
AI summary
A sensor for verifying value documents is designed to determine a luminescence characteristic of a value document that is moved past the sensor for verification purposes, and the provision of a velocity correction of the luminescence characteristic of the value document in the sensor, resulting in a distortion of the measured luminescence intensities. A reference sensor is used to determine an average velocity dependency of the luminescence characteristic of a reference medium, said average velocity dependency being averaged over both opposite directions of movement and being used to determine a velocity dependency of a corrective factor for the luminescence characteristic. Said determined velocity dependency is used to determine the corrective factor for the luminescence characteristic, said corrective factor applying to the velocity of the movement of the value document during the verification process, and the luminescence characteristic is then corrected by said corrective factor.