Noninvasive Core Temperature Sensing With Periodic Thermal Calibration
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Solution Overview
Problem
Existing noninvasive core body temperature sensors have high energy consumption, limited accuracy, and are dependent on environmental conditions, making them unsuitable for out-of-hospital applications.
Innovation Solution
A noninvasive temperature monitoring system with a pair of temperature sensors separated by a thermal insulation layer, using a heater to calculate thermal conductivity constants, allowing for accurate core body temperature measurement with minimal power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat flow based techniques are used for noninvasive core body temperature sensing, then invasive methods are avoided, but energy consumption is high and accuracy is limited
Solution Approach 1:
The system alternates between measurement mode (sensing temperatures) and calibration mode (heating phase change material), rather than continuous operation. This periodic action reduces overall energy consumption while maintaining measurement capability.
Solution Approach 2:
The patent extracts the heating function into a separate calibration phase using a phase change material, rather than requiring continuous active heating. This separates the sensing function from the calibration function, enabling lower power consumption during measurement.
2Reliability
If heat flow based techniques are used for noninvasive core body temperature sensing, then invasive methods are avoided, but measurement accuracy is limited
Solution Approach 1:
The system changes the thermal parameters of the medium between measurement and calibration modes. During calibration, the phase change material's thermal properties are utilized to establish reference temperatures, which then improve the accuracy of subsequent measurements.
Solution Approach 2:
The system uses the calibration data obtained from the phase change material to feedback and adjust temperature measurements. This feedback mechanism compensates for environmental variations and improves measurement precision.
3Reliability
If continuous measurement mode is used, then core body temperature is continuously monitored, but power consumption increases
Solution Approach 1:
The system implements periodic alternation between measurement mode and calibration mode, allowing continuous monitoring capability while reducing average power consumption through duty cycling.
Solution Approach 2:
The system dynamically switches between different operational modes (measurement and calibration) based on timing signals, optimizing the balance between continuous monitoring and power consumption.
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 system provides accurate core body temperature monitoring with low power consumption, suitable for outdoor use, by alternating between calibration and measurement modes to ensure reliability and efficiency.
Implementation Method 1
a phase change material positioned between the first temperature sensor and the second temperature sensor
Implementation Method 2
The insulation layer is formed with a predetermined thermal conductivity constant
Implementation Method 3
A controller alternates the system between the measurement mode and to the calibration mode, whereupon there is a requirement for recalibration of Ct
Data Source
AI summary
A core body temperature monitoring apparatus placed superdermally over a user's skin, including a first temperature sensor, a second temperature sensor, a thermal insulation layer positioned intermediate the first and second temperature sensor and a heater for heating the apparatus and a subdermal tissue region underlying the user's skin. The subdermal tissue region is configured with variable thermal tissue parameters. A controller includes a switch configured for alternating between a calibration mode, wherein the heater is activated for calculating an instantaneous thermal tissue parameter, and a measurement mode, wherein the heater is inactive and the core body temperature is determined, based on the calculated instantaneous thermal tissue parameter.