MEMS Thermopile Internal Temperature Sensor for High Accuracy
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Solution Overview
Problem
Existing non-heating core body thermometers have low measurement accuracy and responsiveness due to the need for high insulation in the heat insulator, which increases measurement time and disrupts heat flow, resulting in inaccurate temperature readings.
Innovation Solution
A compact internal temperature sensor with a heat flux sensor fabricated through a MEMS process, featuring a thermopile for high accuracy temperature difference measurement, and a thermally conductive member to enhance heat transfer, along with a housing that stabilizes the measurement environment and prevents electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a heat insulator with high insulation is used to measure temperature difference with two temperature sensors, then the temperature difference becomes detectable with intended accuracy, but the heat insulator has large heat capacity causing at least five minutes to obtain stable measurement result
Solution Approach 1:
The patent replaces the conventional mechanical/thermal system using two separate temperature sensors and a bulk heat insulator with a MEMS-based thermopile system. The thermopile directly converts temperature differences into electrical signals through the Seebeck effect, eliminating the need for large heat capacity insulators and enabling rapid thermal equilibrium without sacrificing measurement accuracy.
Solution Approach 2:
The patent changes the fundamental measurement parameter approach by using a thermopile with multiple thermocouples that directly measure temperature difference through voltage output, rather than using separate temperature sensors that require thermal isolation. This parameter change enables both high accuracy and fast response by operating in the electrical domain rather than relying on thermal mass isolation.
2Measurement precision
If a heat insulator with high insulation is used to produce detectable temperature difference, then measurement accuracy improves, but the heat insulator disturbs the heat flow reducing measurement accuracy
Solution Approach 1:
The patent substitutes the heat insulator-based thermal measurement system with an electrical measurement system using a thermopile. This replacement eliminates the contradiction by directly measuring temperature difference through voltage generation from thermocouples, avoiding any disturbance to the natural heat flow path while maintaining high measurement accuracy.
Solution Approach 2:
The thermopile acts as an intermediary element that measures temperature difference without interfering with the heat flow. By converting thermal energy directly into electrical signals through the Seebeck effect, it provides an indirect measurement method that does not require thermal isolation or insulators that would disturb the heat flow.
3Device complexity
If two temperature sensors separated by a heat insulator are used, then the device structure becomes simpler, but the measurement accuracy and responsiveness are reduced
Solution Approach 1:
The patent merges the functions of multiple thermocouples into a single integrated thermopile structure fabricated through MEMS processes. This consolidation maintains structural simplicity while achieving superior measurement accuracy and responsiveness by combining multiple temperature sensing elements into one unified device that directly outputs voltage proportional to temperature difference.
Solution Approach 2:
The patent replaces the conventional approach of using two separate temperature sensors with a thermopile-based electrical measurement system. This substitution maintains device simplicity through single-chip MEMS fabrication while dramatically improving measurement accuracy and responsiveness through direct thermoelectric conversion.
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 sensor achieves higher accuracy and responsiveness in measuring internal temperatures, reducing measurement time and improving accuracy compared to existing technologies.
Implementation Method 1
a thin film including a thermopile that detects a temperature difference between the first temperature measurement part and the second temperature measurement part
Implementation Method 2
The thermally conductive member conducts heat traveling from the object through the substrate to the second temperature measurement part
Data Source
AI summary
An internal temperature sensor includes substrates with one surface to be placed in contact with a measurement surface of an object to measure an internal temperature of the object, a heat flux sensor on another surface of the substrates, and a temperature sensor. The heat flux sensor is fabricated through a MEMS process and includes first and second temperature measurement parts, and a thin film including a thermopile to detect a temperature difference between the first and second temperature measurement parts. The thin film is supported by a thermally conductive member to form a space between the first temperature measurement part and the substrates and to extend parallel to the substrates. The thermally conductive member conducts heat traveling from the object through the substrates to the second temperature measurement part. The temperature sensor measures the temperature of a part of the substrates that is in contact with the thermally conductive member.