Elastomeric Encapsulated MEMS Pressure Sensor for High-Force Measurement
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Solution Overview
Problem
Existing semiconductor pressure sensors face limitations in measuring high pressures due to low full-scale values and require costly, bulky packaging, which restricts their application in automotive and other high-pressure environments.
Innovation Solution
A packaged pressure sensor design featuring a container with a PDMS filling layer and a MEMS sensor chip, where the PDMS transfers pressure to a membrane, allowing for high directional force measurement and uniform force application, overcoming the limitations of existing sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If semiconductor pressure sensors are used for high-pressure measurement, then measurement capability is improved, but packaging size and cost increase
Solution Approach 1:
The patent combines the force application surface and pressure transmission function into a single integrated container structure. The container directly transmits applied force to the elastomeric material and MEMS sensor without requiring separate oil-filled chambers or intermediate components, thereby reducing packaging volume while maintaining high-pressure measurement capability.
Solution Approach 2:
The patent extracts and eliminates the oil filling medium from the pressure transmission system. By using solid elastomeric material (such as silicone rubber) instead of liquid oil, the design removes the need for fluid-tight containers and associated sealing components, significantly reducing packaging complexity and size while enabling high-pressure measurement up to 100 bar.
2Measurement precision
If semiconductor pressure sensors are used for high-pressure measurement, then measurement capability is improved, but packaging cost increases
Solution Approach 1:
The patent employs inexpensive elastomeric materials (such as silicone rubber or polyurethane) for the pressure transmission element instead of costly ceramic or metal packaging. These polymers can be manufactured through simple molding processes, dramatically reducing packaging costs while maintaining functionality for high-pressure measurements up to 100 bar.
Solution Approach 2:
The patent changes the physical state of the pressure transmission medium from liquid (oil) to solid (elastomeric material). This parameter change enables the use of simpler manufacturing processes such as injection molding or compression molding, reducing production complexity and cost while achieving the required pressure transmission performance for high-pressure applications.
3Manufacturing precision
If oil filling is used for force distribution, then force uniformity is improved, but fluid-tightness requirement increases complexity
Solution Approach 1:
The patent extracts the liquid oil medium from the pressure transmission system and replaces it with solid elastomeric material. This elimination removes the requirement for fluid-tight sealing, simplifying the container design and manufacturing while maintaining uniform force distribution through the inherent elasticity and conformability of the solid polymer material.
Solution Approach 2:
The patent substitutes the liquid-based hydraulic pressure transmission system with a solid-based elastic deformation system. The elastomeric material transmits force through elastic compression rather than fluid pressure, eliminating the need for fluid-tight containment and simplifying the overall device structure while achieving uniform force application to the MEMS sensor.
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
Enables accurate measurement of forces in the range of 0.1-100 kN with reduced size and cost, enhancing the versatility and precision of pressure sensing in various applications.
Implementation Method 1
A pressure sensor according to any of the preceding claims, wherein the packaged pressure sensor comprises: a container (2) defining an internal cavity (4); a filling layer (12) of elastomeric material arranged in the internal cavity (4) of the container (2)
Implementation Method 2
Formed within the membrane are piezoresistive elements connected together to form a Wheatstone bridge. When subjected to a pressure, the membrane undergoes deformation, causing a variation of resistance of the piezoresistive elements
Data Source
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AI summary
A packaged pressure sensor, comprising: a MEMS pressure-sensor chip; and an encapsulating layer of elastomeric material, in particular PDMS, which extends over the MEMS pressure-sensor chip and forms a means for transferring a force, applied on a surface thereof, towards the MEMS pressure-sensor chip.