Oscillating Thermal Sensor Detection for Small Microplastics

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Solution Overview

Problem

Current methods for detecting microplastics are labor-intensive, require complex equipment, and are limited in size detection, especially for transparent or small microplastics, necessitating a need for alternative and simpler methods.

Innovation Solution

A thermal sensor with a heating element and sensor component is used to detect microplastics by oscillating the heating element and recording the temperature response, allowing for detection based on thermal properties without the need for additional chemicals or complex devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If visual inspection is used to detect microplastics, then the method is simple and requires no additional equipment, but it cannot detect transparent or small microplastic particles (less than 50 μm)

Engineering Contradiction:
Improvesimplicity of detection methodVSAvoiddetection capability for small and transparent microplastics
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces visual inspection (optical/mechanical system) with thermal sensing (thermal field system). The thermal sensor detects microplastics by measuring temperature responses when exposed to thermal radiation, enabling detection of transparent and sub-50μm particles that are invisible to the naked eye while maintaining operational simplicity.

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

Solution Approach 2:

The patent changes the detection parameter from visual/optical properties to thermal properties. By measuring temperature responses and thermal conductivity differences between microplastics and the surrounding medium, the system can detect microplastics based on their thermal characteristics rather than visual appearance.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If chemical analysis methods using fluorescent dyes are used, then microplastics can be visualized, but the color reaction is highly dependent on sample and microplastic type, limiting detection sensitivity for certain types

Engineering Contradiction:
Improvevisualization capability of microplasticsVSAvoiddetection sensitivity across different microplastic types
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces chemical analysis methods (chemical system) with thermal sensing (thermal field system). This substitution eliminates the need for fluorescent dyes and color reactions, providing universal detection capability across all microplastic types based on their inherent thermal properties rather than chemical reactivity.

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

Solution Approach 2:

The patent introduces thermal radiation as an intermediary between the detection system and microplastics. The thermal sensor detects temperature changes caused by microplastics when exposed to thermal radiation, providing a universal detection mechanism that does not depend on microplastic composition or chemical properties.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If microscopy is used to detect microplastics, then sensitivity and resolution are improved and different types can be differentiated, but the detectable size is limited and the method is time- and labor-intensive

Engineering Contradiction:
Improvesensitivity and resolution for microplastic differentiationVSAvoidtime and labor required for detection
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces microscopy (optical system requiring manual operation) with automated thermal sensing. The thermal sensor provides automated detection without manual sample preparation or operator intervention, significantly reducing time and labor while maintaining detection sensitivity through thermal property measurements.

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

Solution Approach 2:

The patent creates a universal detection system that can detect all microplastic types and sizes through thermal properties, eliminating the need for different microscopy techniques for different particle types. The thermal sensor provides multi-functional detection capability in a single system.

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

4Measurement precision

If spectroscopy methods (Raman or Fourier transform infrared) are used, then microplastics can be detected with high sensitivity including particles smaller than 1 μm and structural information can be obtained, but the methods are associated with significant time and expense

Engineering Contradiction:
Improvedetection sensitivity and structural information capabilityVSAvoidtime and cost for analysis
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces spectroscopy methods (complex optical systems) with thermal sensing (simple thermal field system). This substitution maintains detection sensitivity for particles smaller than 1 μm through thermal property measurements while eliminating the need for expensive and time-consuming spectroscopic analysis.

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

Solution Approach 2:

The patent uses a simple, inexpensive thermal sensor instead of expensive spectroscopic equipment. The thermal sensing system provides a cost-effective alternative that achieves comparable detection sensitivity without the high equipment costs and complex operational requirements of spectroscopy.

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

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 method enables reliable detection of microplastics of various sizes and types with simple handling, facilitating on-site analysis and providing quantitative data on microplastic presence, concentration, and composition.

Implementation Method 1

a heating element is brought into contact with the sample. The heating element is controlled in an oscillating manner using a control signal

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The temperature response of the thermal sensor is recorded by the sensor component. The microplastics in the sample can be detected based on the temperature response.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4610642A1Method and thermal sensor for detecting microplastics
Publication Date: 2025.09.03 HAHN SCHICKARD GESELLSCHAFT FUR ANGEWANDTE FORSCHUNG EV
  • EP4610642A1 patent drawingFigure 1
  • EP4610642A1 patent drawingFigure 2A~2B
  • EP4610642A1 patent drawingFigure 3A~3B

AI summary

In a first aspect, the invention relates to a method for detecting microplastics in a sample. In the method according to the invention, a thermal sensor comprising a heating element and a sensor component is first provided. The sample is brought into contact with the heating element. The heating element is controlled in an oscillating manner by means of a control signal. The temperature response of the thermal sensor is recorded by the sensor component. The microplastics in the sample can be detected based on the temperature response. Furthermore, the invention relates to a thermal sensor for carrying out the method according to the invention and to a use of the thermal sensor for detecting microplastics in a sample.