Miniature Pressure Sensor Metallic Membrane Hermetic Sealing
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Solution Overview
Problem
Existing pressure sensors face challenges in achieving miniaturization, compatibility with all fluids, and resistance to chemical attacks and temperature variations while maintaining accuracy and reliability, particularly in harsh environments.
Innovation Solution
A pressure sensor design featuring a metallic membrane with an electrical insulator and gauges, where the cap is sealed hermetically using continuous metallic tracks, allowing for miniaturization and robustness, and using a ceramic or metal cover with expansion coefficients matching the membrane to enhance thermal stability and fluid compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If silicon membrane technology is used, then miniaturization and cost reduction are achieved, but resistance to corrosive fluids deteriorates
Solution Approach 1:
The patent introduces a protective diaphragm made of chemically resistant material (such as metal or ceramic) that acts as an intermediary between the corrosive fluid and the silicon membrane. This diaphragm allows pressure transmission while protecting the sensitive silicon elements from chemical attack, thus enabling miniaturized silicon-based sensors to operate in harsh chemical environments.
Solution Approach 2:
The sensor employs a composite structure combining silicon membrane technology with protective layers of chemically resistant materials. The silicon membrane provides miniaturization benefits while the outer protective diaphragm provides chemical resistance, creating a composite system that achieves both small size and corrosion resistance.
2Object-affected harmful factors
If metallic membrane technology is used, then resistance to chemical attack and temperature is improved, but miniaturization deteriorates
Solution Approach 1:
The protective diaphragm serves as an intermediary that enables the use of chemically resistant materials while maintaining compatibility with miniaturization processes. This intermediate layer allows integration of robust materials without sacrificing the ability to manufacture small-scale sensors.
Solution Approach 2:
The patent modifies the thickness and properties of the protective diaphragm to optimize both chemical resistance and miniaturization. By carefully controlling the diaphragm's characteristics, the sensor achieves high resistance to chemical attack and temperature while maintaining a compact size suitable for modern applications.
3Object-affected harmful factors
If protective diaphragm is added to protect silicon membrane, then chemical resistance is improved, but device complexity and bulkiness deteriorate
Solution Approach 1:
The patent employs a thin protective diaphragm that provides chemical resistance while minimizing added complexity and bulk. This thin-film approach allows the protective layer to be integrated seamlessly with the silicon membrane structure, reducing the overall device complexity while maintaining chemical protection.
Solution Approach 2:
The protective diaphragm is merged with the silicon membrane structure through integrated manufacturing processes. The protective layer is formed as part of the sensor assembly, combining the protective function with the sensing function in a unified structure that reduces overall device complexity.
4Measurement precision
If reference pressure cavity is added for absolute measurement, then measurement precision is improved, but device complexity and bulkiness deteriorate
Solution Approach 1:
The reference pressure cavity is nested within the sensor housing, utilizing the available internal volume efficiently. This nested configuration allows the absolute pressure measurement function to be integrated without significantly increasing the overall sensor size or complexity, as the reference cavity shares space with other sensor components.
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 high levels of miniaturization while maintaining compatibility with most fluids and offering robustness to stresses and strains, improving dynamic measurement responses and reducing the number of components required for assembly.
Implementation Method 1
a pressure sensor intended to measure the pressure of a fluid comprising: a metallic membrane intended to be in contact with said fluid and on which are stacked an electrical insulator and at least one gauge for measuring the deformation of said membrane
Implementation Method 2
this deformation being measured by virtue of resistive strain gauges deposited on the membrane. The gauges change resistive value while following the deformation of the membrane
Implementation Method 3
at least one metallic zone, located in a plane parallel to said plane P, for hermetic sealing of said cap on said sensitive measuring element
Data Source
AI summary
A pressure sensor to measure the pressure of a fluid comprises: a metallic membrane to be in contact with the fluid and on which are stacked an electrical insulator and at least one gauge for measuring the deformation of the membrane, the whole forming a sensitive measuring element a cap comprising: a cover comprising a cavity and holes; conductors located in the holes, the sensitive element exhibiting a face opposite the cap and located in a plane P; wherein the sensor comprises: at least one metallic zone, located in a plane parallel to said plane P, for hermetic sealing of the cap on the sensitive measuring element; continuous metallic tracks comprising parts for picking up contact with the conductors and parts for picking up contact with at least the gauge. A method for manufacturing the pressure sensor is also provided.