Full-Glass Microwave Door Shielding With Conductive Coating

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Solution Overview

Problem

Microwave oven doors are typically thick, heavy, and opaque due to metal usage, which limits transparency and increases weight, while existing solutions for transparency, such as glass panels, do not effectively prevent microwave leakage.

Innovation Solution

A door design featuring a conductive coating on the inner glass surface that contacts a conductive material on the front plate of the cooking cavity, creating a ground loop to prevent microwave leakage while maintaining transparency, using conductive rubber or thermoplastic elastomer with metal or carbon fillers, and glass surfaces for visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal plates are used to prevent microwave leakage, then microwave safety is improved, but door transparency and weight are worsened

Engineering Contradiction:
Improvemicrowave leakage preventionVSAvoiddoor transparency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent extracts the microwave shielding function from traditional solid metal plates and relocates it to a conductive coating layer applied on the glass door surface. This separation allows the door to maintain glass transparency while providing equivalent microwave protection through the conductive layer

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a composite structure combining glass (for transparency) with a conductive coating material (for microwave shielding). This composite approach integrates the beneficial properties of both materials: the optical clarity of glass and the electromagnetic shielding capability of conductive materials

Inventive Principle:
Principle #40Composite materials

2Reliability

If metal plates are used to prevent microwave leakage, then microwave safety is improved, but door weight and thickness are worsened

Engineering Contradiction:
Improvemicrowave leakage preventionVSAvoiddoor weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent extracts the shielding function from bulky metal plates and implements it through a thin conductive coating layer on the glass door. This reduces the door's weight significantly while maintaining the microwave leakage prevention function

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a thin conductive coating film applied on the glass door surface to provide microwave shielding. This thin film approach replaces traditional thick metal plates, achieving the same protective function with minimal added weight and thickness

Inventive Principle:
Principle #30Flexible shells and thin films

3Illumination intensity

If glass panels are used to increase transparency, then door transparency is improved, but microwave leakage prevention is worsened

Engineering Contradiction:
Improvedoor transparencyVSAvoidmicrowave leakage prevention
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent creates a composite door structure where glass provides transparency and a conductive coating layer provides microwave shielding. The combination maintains optical clarity while preventing microwave leakage through the conductive properties of the coating

Inventive Principle:
Principle #40Composite materials

4Weight of moving object

If conductive coating is applied on glass door surface, then door transparency and weight are improved, but ground loop formation must be prevented

Engineering Contradiction:
Improvedoor weightVSAvoidground loop prevention
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent segments the conductive coating into discrete patterns or isolated regions on the glass door surface, rather than using a continuous coating. This segmentation prevents the formation of closed conductive loops while maintaining the microwave shielding effectiveness of the conductive material

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies conductive coating only in specific local areas on the glass door where it is needed for microwave shielding, rather than covering the entire surface. This localized application prevents ground loop formation while providing adequate protection in critical areas

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 allows for a thinner, lighter, and more transparent microwave oven door that effectively prevents microwave leakage, enabling safe viewing of the cooking cavity without compromising safety.

Implementation Method 1

A conductive material 10 is coupled to a front plate 8 of the cooking cavity 6... The inner glass surface 16 includes a conductive coating that contacts the conductive material on the front plate of the cavity when the door is closed, creating a ground loop for the door

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP3551935B1Microwave oven with full glass door
Publication Date: 2022.05.25 WHIRLPOOL CORP
  • EP3551935B1 patent drawingFigure 1~2
  • EP3551935B1 patent drawingFigure 3
  • EP3551935B1 patent drawingFigure 4

AI summary

A microwave oven (2) with a full glass door (12) for preventing microwave leakage from the cooking cavity (6) of the microwave oven (2) is provided. The front plate (8) of the cooking cavity (6) has a conductive material (10), such as a rubber with conductive filler. The inner glass surface (16) of the door (12) has a conductive coating that creates a ground loop with the conductive material (10) on the front plate (8) of the cooking cavity (6) to prevent microwave leakage from the cooking cavity (6).