LED Reference Light Source Temperature Compensation

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Solution Overview

Problem

Optical measurements related to radiation brightness are challenging to standardize due to temperature variations, especially in industrial settings where commercial reference light sources are expensive and manual compensation is inefficient.

Innovation Solution

A method and device for determining a temperature-stabilized operating point of a reference light source arrangement using an LED, which includes a programmable voltage source, a series resistor, and a Peltier element to maintain consistent light intensity across varying temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a commercial reference light source is used for calibration, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecalibration accuracyVSAvoidsystem cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces expensive commercial reference light sources with a cost-effective LED-based reference source that can be easily manufactured and replaced. The LED reference source uses standard electronic components (LED, resistor, capacitor) that are inexpensive and readily available, eliminating the need for costly commercial calibration devices while maintaining sufficient calibration accuracy for industrial applications.

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

Solution Approach 2:

The patent employs temperature compensation by adjusting electrical parameters (voltage/current) of the LED based on temperature sensor feedback. This dynamic parameter adjustment compensates for temperature-induced drift in the LED's output characteristics, maintaining stable calibration accuracy across varying temperatures without requiring expensive temperature-controlled environments.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If manual temperature compensation is performed by laboratory staff, then measurement precision is maintained, but productivity decreases

Engineering Contradiction:
Improvetemperature compensation accuracyVSAvoidmeasurement throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent implements automatic temperature compensation where the system self-regulates without human intervention. A temperature sensor continuously monitors the LED temperature, and a control circuit automatically adjusts the drive voltage/current to compensate for temperature effects. This eliminates the need for manual compensation by laboratory staff, maintaining measurement precision while significantly improving productivity and measurement throughput.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs a closed-loop feedback system where temperature sensor output is fed back to the control circuit, which adjusts the LED drive parameters in real-time based on the temperature deviation. This automatic feedback mechanism maintains calibration accuracy across temperature variations without requiring manual intervention, thereby preserving measurement precision while enhancing operational efficiency.

Inventive Principle:
Principle #23Feedback

3Device complexity

If temperature variations are not compensated, then device complexity is reduced, but measurement precision deteriorates

Engineering Contradiction:
Improvesystem simplicityVSAvoidcalibration stability
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent compensates for temperature effects by dynamically adjusting electrical parameters (voltage/current) of the LED based on temperature sensor feedback. This parameter adjustment counteracts temperature-induced changes in LED output, maintaining stable calibration accuracy across varying temperatures without requiring complex mechanical or environmental control systems.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces complex mechanical or environmental temperature control systems (such as temperature-controlled chambers or active cooling/heating devices) with an electronic parameter adjustment approach. By using electronic feedback control to adjust drive parameters, the system achieves temperature compensation with minimal added complexity, maintaining both simplicity and measurement precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 a cost-effective, temperature-independent light source for reliable calibration and measurement, ensuring consistent authenticity checks in industrial processes despite temperature fluctuations.

Implementation Method 1

a Peltier element (135) to maintain the LED (110) at a constant temperature

Methodology Applied
Scientific EffectPeltier effect: Peltier Effect

Implementation Method 2

a reference light source arrangement (110) comprising an LED (110)

Methodology Applied
Scientific EffectLight emitting diode effect: Light Emitting Diode

Data Source

PatentEP3492936B1Temperature and intensity calibrated reference light source
Publication Date: 2020.03.04 BUNDESDRUCKEREI GMBH
  • EP3492936B1 patent drawingFigure 1a~1c
  • EP3492936B1 patent drawingFigure 1d~1e
  • EP3492936B1 patent drawingFigure 2

AI summary

A method for determining a temperature-stabilized operating point (225) of a reference light source arrangement comprising an LED, comprises: at a first temperature: recording, under current variation, a first emission characteristic (215) of the reference light source arrangement; at a second temperature: recording, under current variation, a second emission characteristic (220) of the reference light source arrangement; after recording the first emission characteristic (215) and the second emission characteristic (220): finding a non-zero current such that the intensity value associated with this current on the first emission characteristic (215) has the same intensity value as the intensity value associated with this current on the second emission characteristic (220); and selecting the current thus determined as the operating point current (225).