Capacitive Sensing Assembly Using Conductive Plastic for Contoured Interfaces
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Solution Overview
Problem
Conventional capacitive sensing assemblies in controller devices face challenges in forming metal layers over nonconductive interface shapes with various contours, limiting their effectiveness in detecting user proximity and requiring complex assembly processes.
Innovation Solution
The use of conductive plastic, which is lightweight and cost-effective, coupled with a nonconductive interface material and an electrode, allows for precise formation over different geometries, enabling efficient detection of user proximity through surface capacitance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is used in conventional capacitive sensing assemblies, then conductivity is improved, but manufacturing complexity increases due to challenges in forming metal layers over nonconductive interface shapes with various contours
Solution Approach 1:
The patent changes the material parameter from metal to conductive plastic, altering the conductivity characteristics while enabling easier formation over complex nonconductive interface shapes. This material substitution resolves the contradiction by providing adequate conductivity through plastic material that can be more easily manufactured into various contours.
Solution Approach 2:
The patent uses composite materials by combining nonconductive interface material with conductive plastic material. This composite approach allows the sensing assembly to achieve both the necessary electrical conductivity and the manufacturability over complex shapes, as the conductive plastic can be formed over the nonconductive substrate.
2Ease of manufacture
If conductive plastic is used instead of metal, then ease of manufacture is improved, but conductivity decreases
Solution Approach 1:
The patent changes the conductivity parameter acceptance range by using conductive plastic instead of metal. The conductive plastic material provides sufficient conductivity for capacitive sensing applications while enabling easier formation processes, effectively resolving the contradiction by adjusting the conductivity threshold to match the capabilities of plastic materials.
3Manufacturing precision
If conventional metal layer formation processes are used, then manufacturing precision may be maintained, but device complexity increases due to the number of parts and assembly steps
Solution Approach 1:
The patent merges the conductive layer formation with the interface material structure by using conductive plastic that can be directly formed over the nonconductive interface. This consolidation eliminates separate metal layer deposition and assembly steps, reducing the number of parts while maintaining formation precision through direct molding or forming processes.
Solution Approach 2:
The patent adopts a simpler, more disposable-friendly approach by using conductive plastic that can be easily formed and integrated, reducing the need for complex, durable metal assembly processes. This allows for simpler manufacturing and potential cost reduction while maintaining functional precision.
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 solution simplifies the assembly process, reduces the number of parts, and enhances control over conductivity, effectively detecting user proximity and contact area, even with lower conductivity compared to metals, while providing a cost-effective alternative for capacitive sensing systems.
Implementation Method 1
The capacitive sensing assembly detects a proximity of a user to the capacitive sensing assembly... The surface capacitance is based in part on the conductive plastic, the nonconductive interface material, and a proximity of the user's skin to the first surface of the nonconductive interface material
Data Source
AI summary
A capacitive sensing assembly comprises a nonconductive interface material, a conductive plastic, an electrode, and a controller. The capacitive sensing assembly is configured to detect a proximity of skin to the nonconductive interface material. The nonconductive interface material comprises a first surface and a second surface that are opposite one another. The first surface receives contact with the skin. The conductive plastic is coupled to the second surface of the interface material. The electrode is electrically coupled to the conductive plastic and configured to provide an electrical signal. The electrical signal corresponds to a surface capacitance of the nonconductive interface material that is based in part on the conductive plastic, the nonconductive interface material, and the proximity of the skin to the interface material. The controller determines the proximity of the skin based on the electrical signal that corresponds to the surface capacitance.