Pressure Sensor Protrusion Electrode Stress Management
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Solution Overview
Problem
Conventional pressure sensing elements face issues with material fatigue and shorter service life due to stress concentration on elastic electrodes, and they require complex structures to maintain linearity in capacitance changes across varying load applications.
Innovation Solution
A pressure sensing element with a simple structure, featuring a first electrode with protrusions, a second electrode, and two dielectrics, where the first dielectric is flexible and the second dielectric thins upon load application, allowing for increased contact area and capacitance linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pressure sensing element uses a single dielectric layer with an elastic electrode, then the structure remains simple, but stress concentration occurs on the elastic electrode leading to material fatigue and shorter service life
Solution Approach 1:
The dielectric layer is divided into two distinct dielectrics: a first dielectric in contact with the protrusion top and a second dielectric between the first electrode and the first dielectric. This segmentation allows each dielectric to serve specific functions - the first dielectric manages stress at the protrusion tip while the second dielectric provides overall insulation, thereby reducing stress concentration on the elastic electrode and extending service life without requiring complex additional components
Solution Approach 2:
Different regions of the dielectric structure are assigned different properties - the first dielectric is positioned specifically at the protrusion top where stress concentration occurs, while the second dielectric occupies the remaining space. This local differentiation allows targeted stress management at critical locations while maintaining overall structural simplicity
2Manufacturing precision
If a pressure sensing element uses a single dielectric layer, then the structure remains simple, but maintaining linearity in capacitance changes across varying load applications requires complex structures
Solution Approach 1:
The dielectric is segmented into two layers with different positions and properties. The first dielectric at the protrusion top and the second dielectric in the bulk region work together to distribute the electric field more uniformly during load application, enabling linear capacitance changes across varying loads without requiring complex structural modifications
Solution Approach 2:
By changing the dielectric parameters (introducing two dielectrics with different properties at different locations), the capacitance response to load is optimized. The first dielectric at the protrusion top and the second dielectric create a configuration that produces linear capacitance changes across the load range, achieving manufacturing precision without increasing structural complexity
3Manufacturing precision
If the first dielectric is made flexible to increase contact area with the protrusion, then capacitance linearity improves, but stress concentration on the elastic electrode increases
Solution Approach 1:
The first dielectric is positioned specifically at the protrusion top where local flexibility is needed to increase contact area and improve capacitance linearity. The second dielectric occupies the remaining space and provides structural support. This local differentiation allows the flexible first dielectric to improve capacitance response without causing overall stress concentration that would reduce service life
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 pressure sensing element with improved linearity and extended service life by managing capacitance changes effectively across different load ranges without the need for complex structures.
Implementation Method 1
a first dielectric and a second dielectric. The first dielectric is disposed between a top of the at least one protrusion and the second electrode
Implementation Method 2
The pressure sensing element is formed of a conductive elastic material, for example, and is a sensor that performs detection upon application of an external load
Data Source
AI summary
A pressure sensing element according to one aspect of the present disclosure includes a first electrode including at least one protrusion, a second electrode facing the at least one protrusion, and a dielectric disposed between the first electrode and the second electrode. The dielectric includes a first dielectric and a second dielectric. The first dielectric is disposed between a top of the at least one protrusion and the second electrode, and is in contact with each of the top of the at least one protrusion and the second electrode. The second dielectric is disposed between a first portion of the first electrode and the first dielectric. The first portion does not include the at least one protrusion. The at least one protrusion has a higher elastic modulus than the first dielectric.