Ceramic Substrate Water Detection and Ejection Mechanism
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Solution Overview
Problem
Gel-filled pressure sensors in wearable devices are vulnerable to pressure errors due to orientation sensitivity and capillary pressure issues, and existing solutions like expanded-polytetrafluoroethylene (ePTFE) membranes are incompatible with ceramic substrates, which are desirable for their strain resistance.
Innovation Solution
An integrated water detection and ejection mechanism using tightly woven metal mesh layers laminated between ceramic layers, forming a parallel plate capacitor that detects water presence through capacitance changes and evaporates it using resistive heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gel-filled sensors are used to survive water exposure, then reliability in wet environments is improved, but pressure measurement precision deteriorates due to orientation sensitivity and capillary pressure errors
Solution Approach 1:
The patent removes the gel filling from the sensor device entirely. Instead of using gel to prevent water ingress, the invention uses a different approach: a heated chamber that actively removes water vapor. This extraction of the problematic gel material eliminates the source of orientation sensitivity and capillary pressure errors while maintaining water resistance through the alternative water removal mechanism.
Solution Approach 2:
The patent changes the physical state management approach from passive gel containment to active thermal control. By introducing a heater that raises the internal temperature (changing thermal parameters), water vapor is actively removed from the chamber. This parameter change from ambient temperature operation to heated operation eliminates capillary pressure effects while maintaining reliability in wet environments.
2Reliability
If ePTFE membranes are used for water resistance, then reliability in wet environments is improved, but compatibility with ceramic substrates deteriorates due to lamination temperature incompatibility
Solution Approach 1:
The patent removes the ePTFE membrane from the design entirely. Instead of using ePTFE for water resistance, the invention relies on the ceramic substrate's inherent properties and a heated chamber approach. This extraction eliminates the manufacturing incompatibility between ePTFE and ceramic substrates while maintaining water resistance through the thermal water removal mechanism.
Solution Approach 2:
The patent replaces the mechanical barrier approach (ePTFE membrane physically blocking water) with a thermal field approach (heater removing water vapor). This substitution eliminates the need for temperature-sensitive materials like ePTFE, making the design compatible with high-temperature ceramic substrate manufacturing processes.
3Measurement precision
If ceramic substrates are used for strain resistance, then measurement precision is improved, but ease of manufacture deteriorates due to incompatibility with traditional water-resistant materials
Solution Approach 1:
The patent removes the incompatible water-resistant materials (gel and ePTFE) from the design. By eliminating these materials, the invention resolves the manufacturing incompatibility issue while preserving the ceramic substrate's strain resistance properties. Water resistance is achieved through the heated chamber approach instead of incompatible materials.
Solution Approach 2:
The patent replaces material-based water resistance (incompatible with ceramic) with a thermal field-based water removal system. This substitution allows ceramic substrates to be used without compromise, as the thermal approach does not require temperature-sensitive materials and fully leverages the ceramic's strain resistance for improved measurement precision.
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 provides a water-resistant sensor device that eliminates orientation sensitivity errors and is compatible with ceramic substrates, ensuring reliable operation in wet environments by effectively detecting and ejecting water, thus meeting stringent reliability requirements for wearable devices.
Implementation Method 1
forming a parallel plate capacitor that detects water presence through capacitance changes
Implementation Method 2
detects water presence through capacitance changes
Implementation Method 3
evaporates it using resistive heating
Implementation Method 4
evaporates it using resistive heating
Data Source
AI summary
A water detecting and ejecting sensor device includes a housing, a ceramic substrate, an integrated circuit and a sensor. The housing includes a cavity and the integrated circuit is disposed on a ceramic substrate. The sensor is disposed on the integrated circuit. The ceramic substrate includes one or more ports to expose the cavity to a surrounding environment, and each port includes at least two mesh layers.