Capacitive Pressure Sensor with Flexible Membranes
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Solution Overview
Problem
Conventional pressure sensors are expensive to manufacture and require complex signal processing, making them less efficient for applications that require simple and cost-effective pressure differential detection.
Innovation Solution
A pressure sensitive device comprising a ring with a flexible membrane and a perforated membrane, where a threshold pressure differential causes deflection between the conductive portions, enabling an electrical change without the need for complex signal processing, utilizing a simple switch or variable capacitor mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional pressure sensors are used, then measurement precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent extracts the essential pressure sensing function from complex sensor systems and implements it through a simple capacitive structure consisting of two conductive membranes separated by a dielectric layer. This eliminates the need for complex signal processing circuits while maintaining adequate measurement precision for flow detection applications.
Solution Approach 2:
The invention uses inexpensive materials such as conductive polymers, metal foils, or conductive ink deposited on flexible substrates to create the capacitive sensing elements. This approach prioritizes cost-effectiveness and simplicity over using expensive, high-precision conventional pressure sensors.
2Measurement precision
If conventional pressure sensors are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent employs low-cost materials and simple fabrication techniques including depositing conductive material on flexible substrates, lamination, and basic assembly processes. This dramatically reduces manufacturing costs compared to conventional pressure sensors while maintaining sufficient measurement precision for the intended application.
Solution Approach 2:
The invention changes the sensing mechanism from piezoresistive or capacitive semiconductor-based sensing to a simple parallel-plate capacitor structure where the capacitance change directly reflects pressure differential. This parameter change enables use of inexpensive materials and simplifies the manufacturing process.
3Ease of manufacture
If simple membrane structure is used, then ease of manufacture is improved, but measurement precision may deteriorate
Solution Approach 1:
The patent applies local quality by creating concentrated conductive regions or patterns on the flexible substrates, and by optimizing the dielectric layer thickness and material properties in specific areas. This enhances the capacitive response to pressure differential while maintaining the overall simplicity and ease of manufacture of the membrane structure.
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 cost-effective and power-efficient means of detecting pressure differentials, suitable for applications like electronic inhalation devices, with significant manufacturing simplicity and reduced power consumption.
Implementation Method 1
a threshold pressure differential across the pressure sensitive device causes deflection between the conductive portions of the flexible membrane and the perforated membrane to change an electrical property
Data Source
AI summary
A pressure sensitive device includes a ring having a central axis, first side and second side. The ring includes a dielectric portion parallel to the central axis and between the first and second sides. A flexible membrane is connected to a periphery of the ring on the first side, the flexible membrane including a conductive portion. A perforated membrane is connected to a periphery of the ring on the second side. The perforated membrane is spaced apart and electrically isolated from the flexible membrane by the ring below a threshold pressure differential across the pressure sensitive device. The perforated membrane includes an opening therethrough and a conductive portion facing and corresponding to the conductive portion of the flexible membrane such that a threshold pressure differential across the pressure sensitive device causes deflection between the conductive portions of the flexible membrane and the perforated membrane to change an electrical property.