Capacitive Micro Pressure Sensor With Segmented Membranes
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Solution Overview
Problem
Existing pressure sensors face challenges in efficiently measuring pressure across a wide range with minimal material usage and stress, while maintaining sensitivity and durability, especially in industrial, medical, and biological applications.
Innovation Solution
A micro pressure sensor design featuring a chamber with multiple membranes and ports, anchored between opposing walls, utilizing a capacitance measurement circuit to convert measured capacitance into pressure, and fabricated using microelectromechanical systems (MEMS) techniques, allowing for flexible membrane patterns and inexpensive production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force collector type pressure sensor uses a piezoresistive strain gauge or piezoelectric element to detect strain, then the sensor can measure pressure, but the material usage and stress on the sensing element increase, reducing durability and sensitivity
Solution Approach 1:
The patent replaces the traditional mechanical strain detection method (piezoresistive strain gauge or piezoelectric element) with a capacitive sensing mechanism. The membrane's deflection changes the capacitance between electrode layers, converting mechanical motion into an electrical signal without requiring stress-bearing sensing materials, thus improving both sensitivity and durability
Solution Approach 2:
The patent changes the detection parameter from mechanical strain (force collector type) to capacitance (capacitive type). By measuring changes in capacitance caused by membrane deflection, the system achieves pressure measurement without the material stress and durability issues inherent in strain-based methods
2Measurement precision
If a capacitive type pressure sensor uses a diaphragm and pressure cavity to create a variable capacitor, then the sensor can detect strain due to applied pressure, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent divides the pressure sensor into multiple independent compartments separated by membranes. Each compartment can be independently fabricated and assembled, reducing the overall device complexity while maintaining the capacitive sensing capability. The modular structure allows for simpler manufacturing processes
Solution Approach 2:
The membrane structure serves multiple functions simultaneously: it acts as a mechanical barrier separating compartments, a capacitive element for pressure sensing, and a structural component for the device architecture. This multi-functionality reduces the need for separate components, simplifying the overall device structure
3Quantity of substance
If pressure sensors are fabricated using traditional techniques, then the sensor can be manufactured, but the material usage increases and production cost rises
Solution Approach 1:
The patent employs thin film membranes as the primary structural and sensing elements. These thin films reduce material usage compared to traditional bulk materials, lower production costs, and enable more efficient manufacturing processes while maintaining the necessary mechanical and electrical properties for pressure sensing
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 micro pressure sensor provides wide-range pressure measurements with reduced material usage and stress, enhanced sensitivity, and durability, suitable for various industrial, medical, and biological applications, while being cost-effective to produce.
Implementation Method 1
the fluid directed into the first set of ports that are inlets causing the plural membranes disposed in the chamber to flex according to pressure differences between the fluid flow pressure and a reference pressure applied to the second set of ports that are outlets
Implementation Method 2
a controller converts measured capacitance into a pressure
Data Source
AI summary
A micro pressure sensor includes a body having a compartmentalized chamber provided by membranes anchored between opposing walls of the body and carrying electrodes disposed on surfaces of the membranes. The body has a first pair of opposing walls and a second pair of opposing walls orthogonal to the first pair that define a chamber, a plurality of membranes having a correspond electrode layer over a surface, the plurality of membranes disposed in the chamber, anchored between the first pair of opposing walls of the body to provide plural compartments, a first set of ports coupled to a first set of the plural compartments, the first set of ports disposed in corresponding portions of a first one of the first pair of opposing walls of the body, with a second one of the first pair of opposing walls of the body being a solid portion of the body; and a second set of ports coupled to a second different set of the plural compartments, the second set of ports disposed in corresponding portions of the second one of the first pair of opposing walls of the body, with the first one of the first pair of walls of the body being a solid portion of the body.