Overvoltage-protected household appliance

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Solution Overview

Problem

Existing domestic appliances lack effective overvoltage protection and electromagnetic compatibility, particularly in household appliances with induction heating elements, which can lead to safety hazards and operational inefficiencies.

Innovation Solution

A domestic appliance design featuring a glass ceramic base body with a metallic coating and an insulating area providing overvoltage protection of at least 1500V, achieved through a metallic layer with sections electrically insulated by a protective layer, preferably produced by laser processing, ensuring safe operation and improved electromagnetic compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a metallic coating is applied to the base body for electromagnetic compatibility and sensing functions, then electromagnetic compatibility is improved, but the risk of electrical discharge and overvoltage damage increases

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

Solution Approach 1:

The metallic coating is divided into multiple electrically insulated sections, with at least one sensor section and at least one grounding section separated by insulating areas. This segmentation prevents electrical discharge between sections while maintaining electromagnetic compatibility, resolving the contradiction between conductivity needs and overvoltage protection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

An insulating area is introduced as an intermediary element between the sensor section and grounding section of the metallic coating. This insulating barrier prevents direct electrical contact, blocking the harmful effect of overvoltage and electrical discharge while allowing both sections to maintain their respective functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the insulating area provides high overvoltage protection (at least 1500V), then operating safety is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improveoperating safetyVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating properties of the metallic coating are modified by changing local parameters (creating insulating areas with specific electrical resistance of at least 10^10 ohm·cm at 20°C and overvoltage protection of at least 1500V). This parameter change approach allows achieving high safety standards while using the existing coating material, reducing manufacturing complexity compared to adding separate insulating components.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the metallic layer thickness is increased to improve electromagnetic shielding, then electromagnetic compatibility is improved, but the capacitive sensing performance deteriorates

Engineering Contradiction:
Improveelectromagnetic shieldingVSAvoidcapacitive sensing performance
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

Different regions of the metallic coating are assigned different functions: sensor sections with optimized thickness for capacitive sensing (20-100 nm) and grounding sections for electromagnetic shielding. This local quality differentiation allows each section to perform its specific function optimally without compromising the other, resolving the contradiction between shielding and sensing performance.

Inventive Principle:
Principle #3Local quality

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 solution enhances operating safety by preventing electrical discharges and sparks, maintains compliance with safety standards, and improves user convenience and electromagnetic compatibility, particularly when integrated with induction heating elements.

Implementation Method 1

an insulating area which electrically insulates the sections from one another

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

the insulating region is produced by laser ablation

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 3

improves electromagnetic compatibility, particularly when integrated with induction heating elements

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 4

one of the sections representing a sensor surface of a capacitive proximity sensor

Methodology Applied
Scientific EffectCapacitive sensing: Capacitance

Data Source

PatentEP2745055B1Overvoltage-protected household appliance
Publication Date: 2017.05.17 BSH HAUSGERATE GMBH
  • EP2745055B1 patent drawingFigure 1a~1b
  • EP2745055B1 patent drawingFigure 2~3

AI summary

The invention proceeds from a household appliance device which comprises a main part (10a; 10b; 10c) and at least one layer (12a; 12b; 12c) that is arranged on at least one side section (14a; 14b; 14c) of the main part (10a; 10b; 10c) and has at least two metallic portions (16a, 18a; 16b, 18b; 16c, 18c) and an insulation region (20a; 20b; 20c) which insulates the portions (16a, 18a; 16b, 18b; 16c, 18c) electrically from one another. In order to provide a household appliance device of the type in question which has increased operating safety, the insulation region (20a; 20b; 20c) is designed to provide an overvoltage protection of at least 1500 V.