ESD Protection Ring in Motor Vehicle Switchgear

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Solution Overview

Problem

Modern motor vehicle electrical switching devices are vulnerable to electrostatic discharge (ESD) from user contact, which can cause damage despite existing protection solutions requiring complex circuitry and unreliable charge dissipation.

Innovation Solution

An electrical switching device with a grounded, electrically conductive housing or actuating element featuring a defined air gap and a metallic or metallized surface, where the charge is directed to earth via the air gap, preventing uncontrolled penetration through insulating materials and ensuring safe dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plastic surface is used for the switching device, then insulation is provided, but electrostatic charge can break through uncontrolled and cause damage

Engineering Contradiction:
Improveprotection against ESD damageVSAvoiduncontrolled electrostatic discharge
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A metallic element is introduced as an intermediary between the plastic surface and the internal electronics. This metallic element serves as a charge collector that intercepts electrostatic discharge from the user's fingertip and directs it to a defined ground connection, preventing uncontrolled breakdown of the plastic insulation and protecting sensitive internal components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If existing ESD protection circuits are implemented, then some protection is provided, but complex circuitry is required

Engineering Contradiction:
ImproveESD protectionVSAvoidcircuitry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The complex semiconductor ESD protection circuits are extracted and replaced with a simple metallic element and ground connection system. The protective function is achieved through basic electrostatic principles rather than active electronic components, significantly reducing device complexity while maintaining protection effectiveness.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a metallic element is added for charge collection, then ESD protection is improved, but device structure becomes more complex

Engineering Contradiction:
Improvecharge dissipation reliabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The metallic element is designed to serve multiple functions: it acts as a charge collector for ESD protection, provides a visible decorative feature on the switching device surface, and serves as an electrical connection element to the ground path. This multi-functionality reduces the need for additional separate components, minimizing structural complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Effectively prevents damage to sensitive electrical components by ensuring electrostatic charges are safely dissipated, maintaining a simple structure and avoiding complex circuitry, thus enhancing ESD protection.

Implementation Method 1

the user or his fingertip is electrostatically charged and this electric charge is transferred to the switching device when he touches it. This can lead to an electrostatic discharge (ESD).

Methodology Applied
Scientific EffectElectrostatic discharge: Electrostatic Discharge

Implementation Method 2

the housing and/or actuating element is assigned grounding via a defined air gap... grounding is provided on or in the electrical switching device, via which the electrical charge is dissipated in a targeted manner

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

the distance between grounding and the metallic element is at its smallest at this air gap, so that the electric charge jumps from the metallic element via the air gap to grounding in a defined manner and only at this air gap

Methodology Applied
Scientific EffectElectrical breakdown: Electric Spark

Data Source

PatentEP2051267B1Electric switchgear in a motor vehicle with an ESD protection device
Publication Date: 2012.03.28 DELPHI TECHNOLOGIES INC
  • EP2051267B1 patent drawingFigure 1
  • EP2051267B1 patent drawingFigure 2
  • EP2051267B1 patent drawingFigure 3

AI summary

The switching device (4) has an electrostatic discharge (ESD) protection device, which is formed by a metallic or metallized element e.g. ring (3), made of chromium, on a surface, where a ground (7) is attached to the protection device over a defined air gap. The ring is designed as an actuating element surrounding an ornamental ring. The protection device is realized by a grounded electrically conductive housing (11) and/or the actuating element, where carbon nano-tubes are added to plastics of the housing and/or the actuating element.