Capacitive Force Sensor with Polymer Dielectric Pressure Rib
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Solution Overview
Problem
Current force sensors with high dielectric constant materials face limitations in capacitance, interactivity, and durability due to high cost, low yield, and high modulus of elasticity, making them unsuitable for capacitive touch sensors and force sensors.
Innovation Solution
A force sensor design featuring a first and second substrate with electrodes and a dielectric interposed between them, where the dielectric surrounds the second electrode and includes a pressure rib connecting to the first electrode, utilizing a polymer dielectric composition with a high dielectric constant and modulus of elasticity to enhance capacitance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high-k filler and elastomer composite is used to increase dielectric constant, then dielectric constant is improved, but adhesive strength with electrode and reaction speed deteriorate
Solution Approach 1:
The patent uses a composite structure consisting of a polymer layer and a gel layer, where the polymer layer provides structural support and the gel layer enhances dielectric properties and adhesion. This composite approach allows simultaneous improvement of adhesive strength and dielectric constant without sacrificing reaction speed
Solution Approach 2:
The patent applies different materials with specific properties to different regions: the polymer layer provides mechanical strength and electrode adhesion, while the gel layer provides high dielectric constant. This local differentiation resolves the contradiction by assigning functions to specific layers rather than using a uniform composite throughout
2Speed
If polymer materials with high dielectric constant are used, then dielectric properties are improved, but modulus of elasticity increases making them unsuitable for force sensors
Solution Approach 1:
The patent creates a composite structure where a soft gel layer with high dielectric constant is combined with a flexible polymer layer. The gel layer provides the necessary dielectric properties and low modulus for force sensing, while the polymer layer maintains overall structural flexibility, enabling the material to be suitable for force sensors despite using high-dielectric-constant materials
Solution Approach 2:
The patent employs thin film structures for both the polymer and gel layers, which inherently provide flexibility. The gel layer acts as a flexible dielectric membrane that can deform under force while maintaining its dielectric function, thus reducing the effective modulus of elasticity of the overall sensor 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 force sensor exhibits superior capacitance, interactivity, and durability, effectively addressing the limitations of existing sensors by reducing electrode gaps and improving dielectric properties through the use of a polymer dielectric composition with conductive fillers and a pressure rib structure.
Implementation Method 1
Dielectric materials necessary for these touch sensors need not only high permittivity of 10 or more but also a low modulus of elasticity and a high adhesive strength with electrode to increase the capacitance
Implementation Method 2
a pressure rib connecting the first dielectric to the first electrode
Data Source
AI summary
The present disclosure relates to a force sensor including a first substrate, a first electrode installed in a pattern on an upper surface of the first substrate, a second substrate disposed above and spaced apart from the first substrate, a second electrode installed in a pattern on a lower surface of the second substrate, facing the first electrode, and a dielectric interposed between the first substrate and the second substrate, wherein the dielectric includes a first dielectric surrounding an outside of the second electrode, and a pressure rib connecting the first dielectric to the first electrode, and a method for preparing the same, and shows a remarkably superior effect to related art, in terms of capacitance, interactivity and durability.