Photothermal Calibration for Thermal Analysis Sample Holders

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Solution Overview

Problem

Current calibration methods for thermal analysis devices are labor-intensive and limited to specific calibration temperatures, making it difficult to achieve accurate temperature measurements across a large temperature range, especially when chemical reactions occur between sample materials, and there are issues with uniform temperature control across multiple sample holders.

Innovation Solution

A method using photothermal measurements to determine correction parameters for each sample holder, allowing for precise calibration of temperature measuring and control devices, ensuring accurate temperature detection and uniform heating across all sample positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional temperature sensors are used to measure sample temperature, then temperature measurement is possible, but measurement precision deteriorates due to spatial separation from the sample and thermal contact issues

Engineering Contradiction:
Improvetemperature measurement precisionVSAvoidsensor placement complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical/physical temperature sensors (thermocouples, resistance thermometers) that require thermal contact with the sample with an optical measurement system. The system uses a light source to illuminate the sample and detects changes in light absorption or reflection that correlate with temperature, eliminating the need for physical sensor contact and the associated placement and thermal resistance problems.

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

Solution Approach 2:

The patent introduces light as an intermediary medium to indirectly measure sample temperature. Instead of directly contacting the sample with a temperature sensor, the system uses light interaction (absorption, reflection, emission) as a mediator to obtain temperature information, thereby avoiding the limitations of direct thermal contact measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If calibration is performed at multiple specific temperatures using melting standards, then calibration accuracy improves at those temperatures, but productivity deteriorates due to the labor-intensive process and restriction to specific temperatures

Engineering Contradiction:
Improvecalibration accuracyVSAvoidcalibration efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent makes the calibration system universal by enabling calibration across a continuous temperature range rather than at discrete temperatures. The optical measurement system can detect temperature-dependent optical properties at any temperature, allowing a single calibration procedure to validate performance across the entire operating range, eliminating the need for multiple temperature-specific calibration points.

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

Solution Approach 2:

The patent exploits changes in optical parameters (absorption coefficient, reflectivity, emission intensity) as temperature varies. By monitoring these parameter changes continuously, the system can perform calibration across a broad temperature range without being restricted to specific phase transition temperatures, thereby improving calibration efficiency while maintaining accuracy.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple calibration measurements are performed on each sample holder with different standard samples, then calibration coverage across temperature range improves, but device complexity and time consumption increase

Engineering Contradiction:
Improvetemperature range coverageVSAvoidcalibration time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent enables continuous temperature measurement and calibration throughout the operating range by using optical detection that can operate at any temperature. This continuous measurement capability eliminates the need for discrete, step-by-step calibration at multiple temperature points, significantly reducing calibration time while maintaining comprehensive temperature range coverage.

Inventive Principle:
Principle #20Continuity of useful action

4Measurement precision

If chemical standard samples are used for calibration, then known reference temperatures are available, but harmful chemical reactions occur between the standard sample and sample holder materials at high temperatures

Engineering Contradiction:
Improvereference temperature accuracyVSAvoidchemical reactions
Core Design Contradiction:
Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent uses light as an intermediary to measure temperature without requiring direct chemical interaction between the calibration standard and the sample holder. The optical measurement system detects temperature through light-sample interactions that do not involve chemical reactions, allowing calibration at high temperatures where chemical standards would react with the holder material.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces chemical-based calibration standards with an optical measurement approach. Instead of relying on chemical phase transitions or reactions at known temperatures, the system uses temperature-dependent optical properties to determine temperature, thereby eliminating harmful chemical reactions between calibration materials and sample holder components.

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

This approach enables more accurate temperature measurement and uniform temperature control, reducing measurement errors and improving the precision of thermal analysis across a broader temperature range by accounting for individual variations in sample holders.

Implementation Method 1

a photothermal measuring device for irradiating a first side of the samples with an electromagnetic excitation pulse and for detecting thermal radiation emitted as a result of the excitation pulse from a second side of the samples opposite the first side

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Data Source

PatentEP3299803B1Method for calibrating the temperature control in thermal analysis of samples
Publication Date: 2022.04.20 NETZSCH GERATEBAU GMBH
  • EP3299803B1 patent drawingFigure 1
  • EP3299803B1 patent drawingFigure 2~3
  • EP3299803B1 patent drawingFigure 4

AI summary

The invention relates to a method for calibrating a device (10) for the thermal analysis of samples (P1 to P4). The method according to the invention comprises: performing photothermal measurements using a photothermal measuring device (18, 20, 22) of the device (10) on a specific sample, which for this purpose is successively held in several sample holders (14-1 to 14-4) of the device (10) and each subjected to a photothermal measurement, or on several identical samples, which for this purpose are each held in one of the several sample holders (14-1 to 14-4) and each subjected to a photothermal measurement, wherein in the photothermal measurements a first side of the respective sample is irradiated with an electromagnetic excitation pulse and a thermal radiation emitted as a result of the excitation pulse from a second side of this sample opposite the first side is detected;Comparing the results of the photothermal measurements for the multiple sample holders (14-1 to 14-4); determining at least one correction parameter for each sample holder (14-1 to 14-4) based on a result of the comparison; and calibrating a temperature measuring device (26-1 to 26-4) of the device (10) and/or temperature control devices (16-1 to 16-4) of the device (10) based on the determined correction parameters.