Capacitive Pushbutton for Motor Vehicles Using Metallized Electrodes
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Solution Overview
Problem
Existing pushbuttons for motor vehicles are complex and costly to manufacture, with electronic contacts that often interfere with the haptic feedback, and lack efficient touchless operation for selecting functions outside the driver's field of view.
Innovation Solution
A capacitive pushbutton design where a metallic area on the surface forms one electrode, and the user's finger forms the second electrode, allowing for a simple, economical construction with touchless operation and minimized haptic interference, using additional capacitors between housing walls to maintain contact without mechanical contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electronic contacts are used in the pushbutton, then reliable electrical connection is achieved, but the haptic feedback is interfered with and the construction becomes complex
Solution Approach 1:
The patent replaces traditional mechanical electronic contacts with a capacitive sensing system. The pushbutton surface is metallized to form one electrode of a capacitor, while a corresponding electrode is placed on the housing. When a user touches or approaches the button, the capacitive coupling changes, enabling touchless detection and actuation. This eliminates mechanical wear and haptic interference while maintaining reliable electrical connection through electronic sensing.
Solution Approach 2:
The patent introduces a dielectric layer between the metallized pushbutton surface and the housing electrode, creating a capacitive coupling mechanism. This intermediary layer enables electrical sensing without direct contact, allowing the system to detect user input through capacitive changes while isolating the electrical components from mechanical wear and haptic interference.
2Reliability
If traditional mechanical contacts are used, then robust electrical connection is achieved, but contact erosion and corrosion occur over time
Solution Approach 1:
The patent replaces mechanical contact-based electrical connections with a capacitive sensing system. The metallized surface of the pushbutton forms one electrode, and a corresponding electrode on the housing forms the other. Electrical connection is achieved through capacitive coupling rather than direct mechanical contact, eliminating erosion and corrosion while extending service life.
3Ease of operation
If multiple electrodes and capacitors are implemented, then touchless sensing is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines the pushbutton surface metallization with the capacitive sensing function, using the same metallized layer as both the operational surface and one electrode of the capacitor. This integration reduces the number of separate components and simplifies manufacturing while maintaining touchless sensing capability.
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 design results in a robust, economical, and haptic-friendly pushbutton that is resistant to impact, shock, and wear, enabling efficient capacitive sensing and visualization of button selection without contact erosion or corrosion, and allows for compact and reliable operation of motor vehicle controls.
Implementation Method 1
a capacitive pushbutton operating on a capacitive basis... a capacitor, which forms the capacitance, includes a metallic area applied to an inner or outer side of a surface facing the user
Data Source
AI summary
The invention concerns an operating element, in particular a pushbutton, for a motor vehicle, having at least of a touch-sensitive pushbutton operating on a capacitive basis and a housing, wherein the pushbutton is movably mounted in the housing, wherein a capacitor that forms the capacitance is composed of a metallic area applied to an inner or outer side of a surface facing the user, and the metallic area forms an electrode of the capacitor that is electrically contacted in the housing.