Photonic Marker Lifetime Sensing with Low-Frame-Rate Cameras

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Solution Overview

Problem

Evaluating the photoluminescence lifetime of commercially available photonic markers is costly and requires complicated handling due to the need for high-speed cameras.

Innovation Solution

Utilizing a photonic marker comprising a host material like rare earth element oxysulfide or strontium aluminate doped with Eu 3+ or Eu 2+ as a dopant, excited by a pulsed light source and detected by a video camera with a frame rate of 20-2000 fps, allowing for time-resolved photoluminescence intensity measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high-speed cameras are used to evaluate photoluminescence lifetime, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvephotoluminescence lifetime measurementVSAvoiddetection system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent changes the photoluminescence lifetime parameter of the marker material itself (from microseconds to milliseconds range) to match the temporal resolution of standard video cameras, enabling measurement with conventional equipment while maintaining precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a photoluminescence response that can be captured by standard video camera frame rates, effectively creating a simplified copy of the measurement process that doesn't require specialized high-speed imaging equipment

Inventive Principle:
Principle #26Copying

2Measurement precision

If high-speed cameras are used to evaluate photoluminescence lifetime, then measurement precision is improved, but cost increases

Engineering Contradiction:
Improvephotoluminescence lifetime measurementVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent modifies the photoluminescence lifetime parameter of the marker to be in the millisecond range, which is detectable by standard video cameras, thereby eliminating the need for expensive high-speed camera systems while maintaining measurement capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses standard video cameras (common, inexpensive devices) instead of specialized high-speed cameras, making the measurement system affordable and accessible for widespread use in authentication and temperature sensing applications

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If specialized detectors are used for photoluminescence evaluation, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvephotoluminescence intensity detectionVSAvoidhandling
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent enables standard video cameras (multi-functional devices already present in smartphones and computers) to perform photoluminescence lifetime measurement, eliminating the need for specialized detectors and simplifying operation for end users

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent creates a photoluminescence signal that can be captured by conventional video recording equipment, allowing the measurement process to be copied using standard devices rather than requiring specialized scientific instrumentation

Inventive Principle:
Principle #26Copying

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

Enables cost-effective and easy-to-handle temperature sensing and security marking using low frame rate cameras, such as smartphones, without the need for specialized detectors.

Implementation Method 1

evaluating the photoluminescence of a photonic marker... the photoluminescence intensity which decays over time is also referred to as time-resolved photoluminescence intensity

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

a determination unit for temperature sensing configured to determine the temperature of a sample to which the at least one photonic marker is added by comparing the time-resolved photoluminescence intensity of the at least one photonic marker with a predetermined temperature-dependent photoluminescence profile

Methodology Applied
Scientific EffectTemperature-dependent photoluminescence: Phosphor Thermometry

Data Source

PatentEP4081612B1Photonic markers enabling temperature sensing and/or security marking using low frame rate cameras
Publication Date: 2025.08.20 KARLSRUHER INST FUR TECH
  • EP4081612B1 patent drawingFigure 1
  • EP4081612B1 patent drawingFigure 2
  • EP4081612B1 patent drawingFigure 3

AI summary

The present invention relates to a system, method and computer-program for evaluating the photoluminescence of a photonic marker as well as to a photonic marker for temperature sensing and/or security marking and to the use of the photonic marker for temperature sensing and/or security marking. The photonic marker according to an aspect of the present invention comprises a host material selected from the group consisting of a rare earth element oxysulfide and strontium aluminate, wherein the host material is doped with Eu3+ or Eu2+ as a dopant.