Capacitive Sensor Dielectric Thickness for Uniform Signal
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Solution Overview
Problem
Conventional capacitive sensing touchpad devices with non-flat shapes face challenges in achieving uniform signal output due to non-uniform capacitive coupling and are often costly to design and fabricate.
Innovation Solution
A capacitive sensing apparatus with a capacitive sensor and a plurality of dielectric materials of varying thicknesses is used to maintain constant capacitive coupling across a non-flat physical reference surface, allowing for standard sensing circuitry to be utilized without additional compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a non-flat shaped capacitive sensing touchpad is produced, then aesthetic appeal and ergonomic fit are improved, but uniform signal output is compromised due to non-uniform capacitive coupling
Solution Approach 1:
The patent applies local quality by varying the thickness of dielectric materials at different locations between the capacitive sensor and reference surface. Specifically, the dielectric layer has different thicknesses in different regions, with thicker portions where the reference surface is farther from the sensor and thinner portions where it is closer, thereby localizing the capacitive coupling properties to achieve uniform signal output across the non-flat surface.
Solution Approach 2:
The patent changes physical parameters of the dielectric materials, specifically the thickness parameter, to compensate for the non-uniform distance between the capacitive sensor and the non-flat reference surface. By adjusting the dielectric thickness parameter across different regions, the capacitive coupling is equalized, maintaining uniform signal output despite the non-flat geometry.
2Shape
If a non-flat shaped capacitive sensing touchpad is produced, then aesthetic appeal and ergonomic fit are improved, but design and fabrication costs increase
Solution Approach 1:
The patent implements local quality through region-specific dielectric thickness variations, allowing standard capacitive sensor arrays to be used with non-flat surfaces. This approach avoids the need for custom-designed sensors for each non-flat geometry, thereby reducing overall design and fabrication costs while maintaining aesthetic and ergonomic benefits.
3Ease of manufacture
If uniform dielectric thickness is used with a non-flat reference surface, then fabrication is simplified, but capacitive coupling becomes non-uniform across the surface
Solution Approach 1:
The patent resolves this contradiction by implementing local quality through spatially varying dielectric thickness. Rather than using uniform thickness throughout, the dielectric layer is designed with specific thickness variations at different locations to compensate for the non-flat reference surface geometry, achieving both manufacturability and uniform capacitive coupling.
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
This approach ensures consistent capacitive coupling and sensitivity across the surface, reducing manufacturing costs and maintaining uniform signal output, even on non-flat shapes like concave or convex surfaces.
Implementation Method 1
capacitive coupling between the capacitive sensor and the object proximate to the physical capacitive sensing reference surface is substantially constant across the physical capacitive sensing reference surface
Implementation Method 2
a plurality of dielectric materials disposed between the capacitive sensor and the physical capacitive sensing reference surface
Data Source
AI summary
One embodiment in accordance with the invention includes a capacitive sensing apparatus that includes a capacitive sensor configured to sense an object proximate to a physical capacitive sensing reference surface. The capacitive sensing apparatus also includes a plurality of dielectric materials disposed between the capacitive sensor and the physical capacitive sensing reference surface. Note that at least one of the plurality of dielectric materials has a non-uniform thickness. The plurality of dielectric materials can be configured such that capacitive coupling between the capacitive sensor and the object proximate to the physical capacitive sensing reference surface is substantially constant across the physical capacitive sensing reference surface.