Flexible Heat Flow Sensor for Human Body Measurement
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Solution Overview
Problem
Existing heat flow sensors with inflexibility lead to measurement errors due to heat transfer losses and air layer formation when in contact with curved surfaces like the human body, resulting in inaccurate heat discharge measurements.
Innovation Solution
A heat flow meter with a flexible heat transfer unit and temperature difference measurement unit, where the heat transfer unit has a first member with flexibility and a second member with higher thermal conductivity, and a heat diffusion layer with thermal conductivity greater than 100 W/(m×K), ensuring close contact with the skin surface and minimizing air layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a heat flow sensor with no flexibility is used, then the thermal conductivity is good, but the measurement precision deteriorates due to air layer formation on curved surfaces
Solution Approach 1:
The patent applies this principle by making the heat flow sensor itself flexible through using a flexible substrate and flexible conductive layers. This allows the sensor to conform to curved surfaces like the human body skin without forming air layers, thereby maintaining both good thermal contact and measurement accuracy simultaneously.
Solution Approach 2:
The patent uses composite material structure combining flexible substrate (such as flexible PCB) with conductive layers (such as conductive adhesive or metal traces). This composite structure provides both the flexibility needed for conformal contact and the thermal conductivity required for accurate heat flow measurement.
2Loss of energy
If an attachment with flexibility and good thermal conductivity is used to transfer heat from skin to sensor, then the heat transfer is improved, but heat flows out to other members causing measurement error
Solution Approach 1:
The patent extracts the heat transfer function from a separate attachment and integrates it directly into the sensor structure. The sensor itself becomes the heat transfer medium through its flexible conductive layers, eliminating the need for additional attachment materials that could cause heat loss to other members.
Solution Approach 2:
The patent merges the heat transfer function with the sensing function by integrating the conductive layers directly onto the flexible substrate that contacts the skin. This combination ensures that heat transferred through the attachment is directly measured by the sensor without significant loss to other members.
3Area of stationary object
If the heat flow sensor is brought into direct contact with curved skin surface, then the contact area is improved, but air layers occur reducing actual contact area
Solution Approach 1:
The patent uses a flexible substrate that can deform and conform to the curved surface of the skin. This flexibility allows the sensor to maintain large actual contact area with the skin surface without forming air layers, thereby improving both contact area and measurement accuracy.
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 solution enables accurate measurement of heat discharge from the human body by reducing heat transfer losses and maintaining close contact with the skin surface, thereby improving measurement accuracy.
Implementation Method 1
a heat transfer unit (11) having flexibility and having first and second surfaces confronting each other
Data Source
AI summary
A heat flow sensor includes a heat transfer layer that has first and second surfaces confronting each other and has flexibility and a temperature difference measurement unit that measures a temperature difference between the first and second surfaces of the heat transfer layer. The heat transfer layer includes a first member having flexibility and a second member with higher thermal conductivity than the first member. The thickness of the heat transfer layer is equal to or greater than 0.5 mm, thermal conductivity of the heat transfer layer is equal to or greater than 10 W/(m×K), and Shore hardness of the heat transfer layer is equal to or less than A50.