In-Vivo Core Temperature Estimation via Segmented Thermal Resistors

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Solution Overview

Problem

Conventional methods for measuring core body temperature are invasive, inaccurate, and fail to account for the non-thermal equilibrium state of the body, leading to insufficient estimation of core temperature changes.

Innovation Solution

An in-vivo temperature measurement device with multiple thermal resistors and sensors that estimate core temperature using an estimation model considering non-thermal equilibrium states, incorporating thermal resistance values and time-series data from epidermis and upper surface temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a percutaneous thermometer is used to measure body temperature, then the measurement is non-invasive and easy to perform, but the measurement accuracy is insufficient because it cannot reflect the core temperature

Engineering Contradiction:

Improveease of measurementVSAvoidcore temperature measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent uses thermal resistors as intermediary elements placed between the core temperature source and the measurement point. These thermal resistors with known resistance values create a thermal circuit that allows indirect measurement of core temperature through surface temperature measurements, bridging the gap between non-invasive measurement and core temperature accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the conventional direct thermal contact measurement method with an electrical circuit-based measurement system. By substituting thermal parameters with electrical equivalents (thermal resistance to electrical resistance, temperature to voltage), the system achieves more accurate core temperature measurement while maintaining non-invasive operation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If a conventional estimation model assuming thermal equilibrium is used, then the calculation is simple, but the estimation accuracy is insufficient because the body is always in a non-thermal equilibrium state

Engineering Contradiction:

Improveestimation model complexityVSAvoidcore temperature estimation accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from a static thermal equilibrium model to a dynamic measurement model that accounts for transient thermal states. By measuring temperatures at multiple time points and considering the dynamic thermal behavior of the body, the system accurately estimates core temperature even when the body is in a non-equilibrium state, making the model adaptive to real physiological conditions

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If multiple thermal resistors with different resistance values are used, then the core temperature estimation accuracy is improved, but the device complexity increases

Engineering Contradiction:

Improvecore temperature estimation accuracyVSAvoidnumber of thermal resistors and sensors

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the thermal measurement system into multiple segments with different thermal resistance values. By using multiple thermal resistors with distinct resistance values and corresponding temperature sensors, the system creates a segmented thermal circuit that provides multiple measurement pathways, improving the accuracy of core temperature estimation through redundant and diversified measurement data

Inventive Principle:

Principle #1Segmentation

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 allows for more accurate and continuous estimation of core temperature, reducing errors associated with thermal equilibrium assumptions and improving daily body temperature management.

Implementation Method 1

a plurality of thermal resistors; first temperature sensors and second temperature sensors provided at both ends of the thermal resistors, respectively

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11883133B2Internal body temperature measurement device and internal body temperature measurement method

Publication Date: 2024.01.30 NIPPON TELEGRAPH & TELEPHONE CORP

AI summary

An in-vivo temperature measurement device includes a plurality of thermal resistors, temperature sensors for measuring an epidermis temperature of a living body, and temperature sensors for measuring an upper surface temperature that are provided at both ends of the thermal resistors, respectively, a memory that stores an estimation model of the core temperature of the living body that takes into consideration a non-thermal equilibrium state of the living body, and thermal resistance values of the thermal resistors, and an arithmetic circuit that estimates, based on the plurality of temperatures measured by the temperature sensors and the temperature sensors, the core temperature of the living body using the estimation model and the thermal resistance values, and the thermal resistance values are different from one another.