Oven Muffle Vertical Light Guide with Silicone Shield

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Solution Overview

Problem

Existing oven muffles with lighting devices struggle to evenly illuminate multiple shelves without excessive components, glare, and protection from impacts, as described in prior art solutions like DE102006061793, EP2746676, and EP3193085.

Innovation Solution

A vertical light guide extending from the floor to the roof, coupled with a silicone shell that shields light from glare and protects against impacts, using a heatsink outside the chamber and diffused lighting through silk screen printing on the glass surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single vertical light guide is provided extending from floor to roof, then all shelves can be illuminated with a single light source, but the light guide is directly exposed to the cooking chamber and subject to impacts and contact with cooking agents

Engineering Contradiction:
Improvenumber of light sourcesVSAvoidprotection of light guide
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A reflective support structure acts as an intermediary between the light guide and the cooking chamber environment. This support carries the light guide while protecting it from direct exposure to cooking agents and impacts, yet still allows the light guide to illuminate all shelves effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If surface finishes are applied to portions of the vertical light guide to prevent glare, then user comfort is improved, but the solution becomes costly and the light guide remains exposed to cooking chamber conditions

Engineering Contradiction:
Improveglare reductionVSAvoidmanufacturing cost
Core Design Contradiction:
Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The reflective support serves as a mediator that prevents glare by reflecting light away from the user's line of sight, while also providing mechanical protection. This approach avoids costly surface treatments on the light guide itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Illumination intensity

If multiple dedicated light sources are provided for each shelf, then all shelves can be illuminated effectively, but the number of components increases significantly

Engineering Contradiction:
Improveshelf illuminationVSAvoidnumber of components
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The single vertical light guide is segmented into multiple illumination zones along its length, with each zone illuminating a specific shelf. This allows effective multi-shelf illumination while maintaining a single integrated light source rather than multiple separate components.

Inventive Principle:
Principle #1Segmentation

4Illumination intensity

If a vertical light guide extends through the whole height of the cooking chamber, then all shelves are illuminated, but the light guide is directly exposed to high-temperature cooking environment

Engineering Contradiction:
Improveoverall chamber illuminationVSAvoidexposure to cooking temperature
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The reflective support structure acts as a thermal barrier and mechanical protector, allowing the light guide to extend through the full height for optimal illumination while shielding it from direct exposure to high cooking temperatures and aggressive cooking environments.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 provides uniform illumination of all shelves with reduced components, prevents glare, and ensures easy cleaning and protection from impacts, maintaining the light guide's integrity in high-temperature environments.

Implementation Method 1

a vertical light guide extending from the floor to the roof

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

coupled with a silicone shell that shields light from glare and protects against impacts, using a heatsink outside the chamber

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

diffused lighting through silk screen printing on the glass surface

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP4206544B1Oven muffle provided with a lighting device for illuminating the cooking chamber
Publication Date: 2025.04.02 SMEG
  • EP4206544B1 patent drawingFigure 1
  • EP4206544B1 patent drawingFigure 2~3
  • EP4206544B1 patent drawingFigure 4~5

AI summary

An oven muffle defining a cooking chamber with a front opening, wherein the muffle comprises: a back wall, a roof wall, a floor wall and two side walls; at least one lighting device configured to illuminate the cooking chamber; wherein the lighting device comprises: a vertical light guide extending from the floor wall to beyond the roof wall; an LED source coupled to the end of the light guide outside the cooking chamber; wherein the light guide is arranged inside the cooking chamber at a side wall; the lighting device further comprises a vertical support in the form of a shell made of silicone material which partially embraces the light guide within the cooking chamber so that the light emitted from the light guide towards the opening of the cooking chamber is shielded leaving exposed only a portion of the light guide facing the cooking chamber.