Wearable Temperature Sensor Using Aerogel Insulation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wearable devices face challenges in accurately measuring body temperature due to the size constraints of heat flux sensors, which require a large temperature difference to reduce noise during ADC conversion, but increasing the insulator thickness to achieve this makes the device bulky and difficult to manufacture in a compact form.
Innovation Solution
A heat flux sensor with a stacked structure using a thermally conductive material between two temperature sensors, where the sensors measure voltage differences and amplify them to generate a large temperature difference, allowing for accurate body temperature estimation without increasing the device's volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the thickness of the insulator is increased to obtain a large temperature difference for reducing noise during ADC conversion, then the measurement precision is improved, but the device thickness increases making it difficult to manufacture compact wearable devices
Solution Approach 1:
The patent changes the thermal conductivity parameter of the insulator material by selecting a material with ultra-low thermal conductivity (λ≤0.03W/mK), specifically using aerogel materials. This allows achieving the required temperature difference with a much thinner insulator layer (10-50μm) compared to conventional materials, thus improving measurement precision while maintaining compact device thickness suitable for wearable applications.
2Measurement precision
If conventional insulator materials are used to achieve the required temperature difference, then the measurement accuracy is improved, but the device becomes bulky and difficult to manufacture in compact form
Solution Approach 1:
The patent employs composite material structures by combining ultra-low thermal conductivity aerogel materials with flexible substrate materials (polyimide or polyester) to create a thin-film insulator composite. This composite structure achieves the required thermal insulation performance for accurate heat flux measurement while maintaining flexibility and compactness for wearable device manufacturing.
Solution Approach 2:
The patent utilizes porous aerogel materials with extremely low thermal conductivity (λ≤0.03W/mK) as the insulator layer. The porous structure of aerogel provides exceptional thermal insulation properties in a thin form factor, enabling accurate temperature difference measurement without increasing device thickness, thus facilitating compact wearable device manufacturing.
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 enables the manufacture of compact wearable devices with improved accuracy in body temperature estimation by generating a large temperature difference through amplified voltage differences, enhancing the precision of heat flux calculations and body temperature measurement.
Implementation Method 1
a heat insulating material has a relatively low thermal conductivity in contact with a surface of a body
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A wearable device may comprise: a first temperature sensor configured to measure a first voltage when the wearable device is in contact with a user; a second temperature sensor disposed apart from the first temperature sensor in a thickness direction of the wearable device, and configured to measure a second voltage when the wearable device is in contact with the user; an amplifier configured to amplify a voltage difference between the first voltage and the second voltage; an analog-to-digital, A/D, converter configured to convert the amplified voltage difference in an analog format to a digital signal; and at least one processor configured to estimate a body temperature of the user based on the digital signal representing the amplified voltage difference.