Deep Body Thermometer Sensor Arrangement for Stable Heat Flow

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Solution Overview

Problem

Existing non-heating deep body thermometers face accuracy issues due to variations in the thickness of the thermal resistor and the distance between temperature sensors, which can lead to inconsistent heat flow and measurement errors, especially when the thermal resistor deforms or when different sizes of temperature sensors are used.

Innovation Solution

A deep body thermometer design where the first and second temperature detection units are positioned such that they do not overlap in the thickness direction of the thermal resistor, with a distance between them greater than the thermal resistor's thickness, ensuring stable heat flow and reducing direct heat transfer, and optionally using overlapping wiring patterns to enhance thermal resistance and reduce external perturbations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the thermal resistor thickness and temperature sensor distance are reduced to improve measurement responsiveness, then the measurement speed improves, but the measurement precision deteriorates due to direct heat transfer between sensors and unstable heat flow paths

Engineering Contradiction:
Improvemeasurement responsivenessVSAvoiddeep body temperature measurement accuracy
Core Design Contradiction:
SpeedVSMeasurement precision

Solution Approach 1:

The patent transitions from a one-dimensional stacked arrangement (sensors directly above/below thermal resistor) to a two-dimensional lateral arrangement where sensors are positioned at the same level with spacing greater than thermal resistor thickness. This dimensional change eliminates direct vertical heat transfer paths while maintaining thermal coupling through the thermal resistor, resolving the contradiction between responsiveness and precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces a thermal conductor as an intermediary element between the temperature sensors and the thermal resistor. This intermediary ensures stable and uniform heat distribution to both sensors, eliminating direct sensor-to-sensor heat transfer while maintaining consistent thermal coupling, thereby improving measurement precision without sacrificing responsiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the thermal resistor becomes deformed (bent or crushed) to adapt to body contours, then the ease of operation improves, but the measurement precision deteriorates due to changing heat flow path thickness

Engineering Contradiction:
Improveadaptability to body contoursVSAvoiddeep body temperature measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

By positioning temperature sensors laterally at the same level rather than stacking them vertically, the patent makes the measurement system insensitive to thermal resistor deformation in the thickness direction. The heat flow path length remains stable (equal to sensor spacing) even when the thermal resistor bends or crushes to adapt to body contours.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the critical parameter from thermal resistor thickness to sensor spacing. Since sensor spacing is fixed by the rigid structure and independent of thermal resistor deformation, the heat flow path length remains constant even when the thermal resistor deforms to adapt to body contours, maintaining measurement precision.

Inventive Principle:
Principle #35Parameter changes

3Difficulty of detecting and measuring

If different sized temperature sensors are used to optimize detection capability, then the detection capability improves, but the measurement precision deteriorates due to variations in heat flow path length

Engineering Contradiction:
Improvetemperature detection capabilityVSAvoiddeep body temperature measurement accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent moves sensors to a lateral arrangement at the same level, making the heat flow path length determined by sensor spacing rather than thermal resistor thickness. This allows sensors of different sizes and detection capabilities to be used without affecting the stability of the heat flow path, as the path length is now defined by the rigid sensor positions rather than the deformable thermal resistor thickness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The thermal conductor acts as an intermediary that uniformly distributes heat to both temperature sensors regardless of their sizes. This ensures that both sensors receive consistent thermal energy, allowing different sized sensors with different detection capabilities to operate with stable and accurate measurements.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 configuration allows for stable and accurate deep body temperature measurement regardless of temperature sensor sizes or thermal resistor deformation, minimizing measurement variations and improving accuracy.

Implementation Method 1

heat needs to stably flow (propagate) from the first temperature sensor to the second temperature sensor (that is, in the thickness direction of the thermal resistor) via the thermal resistor

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3431946B1Deep body thermometer
Publication Date: 2021.03.31 MURATA MFG CO LTD
  • EP3431946B1 patent drawingFigure 1
  • EP3431946B1 patent drawingFigure 2
  • EP3431946B1 patent drawingFigure 3

AI summary

A deep body thermometer (1) includes a thermal resistor (113) having a predetermined thermal resistance value, a first temperature sensor (111) and a second temperature sensor (112) that are disposed to sandwich the thermal resistor (113) in a thickness direction of the thermal resistor (113), and a temperature information processing unit (50) (a deep body temperature acquisition unit (511)) configured to acquire a deep body temperature on the basis of the thermal resistance value of the thermal resistor (113), a temperature detected by the first temperature sensor (111), and a temperature detected by the second temperature sensor (112). The first temperature sensor (111) and the second temperature sensor (112) are disposed such that the first temperature sensor (111) and the second temperature sensor (112) do not overlap each other as viewed from the thickness direction of the thermal resistor (113) and a distance between the first temperature sensor (111) and the second temperature sensor (112) is longer than a thickness of the thermal resistor (113).