Shielded Appliance User Interface for ESD-Safe Conductive Front Panels

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Solution Overview

Problem

Household appliance electronic assemblies behind uneartheed electrically conductive front panels are vulnerable to damage from electrical and magnetic fields, leading to potential electrostatic discharges.

Innovation Solution

An electronic user interface with a shielding device, typically a ferromagnetic metal sheet or foil, is placed between the front panel and the electronic assembly to protect it from electrical and magnetic fields without being earthed, using hooks for mechanical and conductive fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an electrically conductive panel part is used in the front panel, then electromagnetic shielding is improved, but the risk of electrostatic discharge damage to electronic assembly increases when not earthed

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidelectronic assembly protection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

A shielding device is introduced as an intermediary element between the electrically conductive panel part and the electronic assembly. This shielding device provides the necessary electromagnetic shielding function while isolating the electronic assembly from direct exposure to electrostatic discharge risks from the unearthed conductive panel part.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The shielding solution is segmented into a separate shielding device that can be independently positioned and configured between the front panel and electronic assembly, rather than integrating shielding directly into the panel part or relying on the electronic assembly's own housing for protection.

Inventive Principle:
Principle #1Segmentation

2Reliability

If protective earthing is implemented for the electrically conductive panel part, then electrostatic discharge protection is improved, but electromagnetic shielding effectiveness decreases

Engineering Contradiction:
Improveelectrostatic discharge protectionVSAvoidelectromagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The shielding device serves as a mediator that provides electromagnetic shielding without requiring an electrical connection to earth, thus avoiding the trade-off between earthing for static protection and shielding for electromagnetic protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional electrical earthing system with a mechanical/physical shielding barrier that achieves electromagnetic protection without relying on electrical connections to ground, thereby eliminating the need to choose between earthing and shielding.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Object-affected harmful factors

If the shielding device is positioned close to the electronic assembly, then shielding effectiveness is improved, but the risk of electrostatic discharge from unearthed conductive panel part increases

Engineering Contradiction:
Improveelectromagnetic interferenceVSAvoidelectronic assembly protection
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The shielding device acts as a protective intermediary that can be positioned close to the electronic assembly without exposing it to electrostatic discharge risks, because the shielding device itself provides the protective barrier against such discharges.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The shielding device provides beforehand protection by being positioned between the potential electrostatic discharge source (conductive panel part) and the electronic assembly, cushioning the electronic assembly from potential damage before it can occur.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 shielding device effectively prevents damage from electrostatic discharges and electromagnetic interference, ensuring the electronic assembly's integrity and electromagnetic compatibility without the need for protective earthing.

Implementation Method 1

a shielding device (8) which shields the electronic assembly (7) from the at least one electrically conductive panel part (5) against electrical and/or magnetic fields

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP3169213B1Electronic user interface comprising a shielding device
Publication Date: 2018.08.15 BSH HAUSGERATE GMBH
  • EP3169213B1 patent drawingFigure 1
  • EP3169213B1 patent drawingFigure 2
  • EP3169213B1 patent drawingFigure 3

AI summary

The invention relates to an electronic user interface (2) having an appliance front cover (3) with an interior side (6), at least one input and/or output means (4) arranged on the appliance front cover (3), and at least one cover part (5) which has an electrically-conductive surface. The electronic user interface (2) according to the invention has an electronic assembly (7) arranged behind the interior side (6) of the appliance front cover (3), and a shielding device (8) shielding the electronic assembly (7) against electric and/or magnetic fields from the at least one electrically-conductive cover part (5). The invention further relates to a household appliance (1) which comprises such an electronic user interface (2).