Core Body Temperature Sensor With Thermal Insulation And Conductive Shield

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Solution Overview

Problem

Current methods for measuring core body temperature are invasive, unreliable due to perfusion variations and ambient temperature changes, and lack accuracy, especially for continuous ambulatory monitoring.

Innovation Solution

A sensor device with a first temperature probe and a second temperature probe thermally insulated by a conductive shield, where the second probe is in contact with the skin, allowing for accurate core body temperature determination using thermal flux models and perfusion parameter measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single temperature probe is placed against the skin to measure core body temperature, then the measurement method is simple and comfortable, but the accuracy is low due to variations in outer thermal resistance caused by perfusion changes

Engineering Contradiction:
Improvemeasurement simplicityVSAvoidcore body temperature accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent divides the measurement system into two separate temperature probes: a first probe (T1) placed against the skin to measure skin temperature, and a second probe (T2) positioned deeper to measure a temperature less affected by perfusion changes. This segmentation allows the system to compensate for variable outer thermal resistance by comparing measurements from both probes, thereby improving accuracy while maintaining ease of operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate computational step that uses the temperature difference between T1 and T2, along with measured perfusion parameters, to calculate a corrected core body temperature. This intermediary calculation process acts as a mediator that transforms the raw probe measurements into an accurate core temperature reading by compensating for perfusion-induced variations in thermal resistance.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If rectal temperature measurement is used to achieve accurate core body temperature, then the measurement accuracy is high, but the method is invasive and obtrusive

Engineering Contradiction:
Improvecore body temperature accuracyVSAvoidmeasurement comfort
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical/invasive rectal probe method with a non-invasive skin-based measurement system. By using thermal flux models that incorporate skin temperature (T1), deeper tissue temperature (T2), and perfusion parameters, the system achieves rectal-grade accuracy without the discomfort or invasiveness of rectal insertion, enabling continuous ambulatory monitoring.

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

Solution Approach 2:

The patent changes the measurement parameters from direct rectal temperature to a calculated core temperature derived from multiple skin-level probes and perfusion measurements. This parameter transformation allows the system to infer core temperature from peripheral measurements combined with perfusion data, achieving the same diagnostic information through a comfortable, non-invasive approach.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If skin temperature measurement is used for core body temperature determination, then the measurement is non-invasive and comfortable, but the reliability is low due to influence from ambient temperature, clothing, and perfusion

Engineering Contradiction:
Improvemeasurement comfortVSAvoidmeasurement robustness
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements a feedback mechanism by continuously measuring perfusion parameters and using them to dynamically adjust the core temperature calculation. The system monitors skin temperature (T1), deeper tissue temperature (T2), and perfusion rate, then feeds this information into a thermal flux model that compensates for ambient temperature and clothing effects, thereby maintaining reliable measurements under varying environmental conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent combines multiple measurement modalities into a composite measurement system: skin temperature sensing, deeper tissue temperature sensing, and perfusion monitoring. By integrating these different measurement types into a unified thermal flux model, the system creates a robust measurement approach that compensates for the weaknesses of individual methods, achieving reliability while maintaining non-invasive comfort.

Inventive Principle:
Principle #40Composite materials

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 solution provides robust, accurate, and comfortable core body temperature measurement, independent of ambient temperature and perfusion changes, with improved power consumption and safety, suitable for long-term use.

Implementation Method 1

a thermal insulator provided between the first and second temperature probes for thermally insulating first and second temperature probes from each other

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

the sensor further comprises a thermally conductive shield covering at least portion of the thermal insulator, the second temperature probe being in contact with the conductive shield

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2459976B1Sensor and method for determining a core body temperature
Publication Date: 2018.11.21 CSEM CENTRE SUISSE D ELECTRONIQUE ET DE MICROTECHNIQUE SA
  • EP2459976B1 patent drawingFigure 1
  • EP2459976B1 patent drawingFigure 2
  • EP2459976B1 patent drawingFigure 3

AI summary

The present disclosure concerns a sensor (1) for measuring a core body temperature of a user, comprising a first temperature probe (2) to be placed against the skin (3) of the user for measuring a first temperature (Tc); a second temperature probe (6) at a distance from the first temperature probe (2), for measuring a second temperature (Td) and; a thermal insulator (4) provided between the first and second temperature probes (2, 6) for thermally insulating first and second temperature probes (2, 6) from each other; characterized in that the thermal insulator (4) embeds the first temperature probe (2), forming a contact surface (7) extending in the plane of the first temperature probe (2) and destined to be in contact engagement with the skin (3); and in that the sensor (1) further comprises a thermally conductive shield (5) covering at least portion of the thermal insulator (4), the second temperature probe (6) being in contact with the conductive shield (5). The sensor allow for performing measurements that are more robust to perfusion and air temperature variations, hence determining the core body temperature with a better accuracy than when conventional sensors are used.