Refrigerator Light Guide Layout for Uniform Shadow-Free Illumination

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional interior lighting in refrigeration appliances often results in uneven illumination and shadowing due to the use of single point light sources, which cannot provide uniform and glare-free lighting across all areas, and existing solutions that achieve better distribution require significant space.

Innovation Solution

The use of a light guide with transparent flat bodies and distributed decoupling structures along the interior walls, including localized projections and polishing to ensure uniform light distribution, combined with additional lighting from a ceiling-mounted source oriented obliquely to illuminate vertical surfaces, minimizes shadowing and optimizes light usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a single point light source is mounted on a side wall, then the lighting structure is simple, but the illumination is uneven and causes shadowing

Engineering Contradiction:
Improveuniformity of illuminationVSAvoidlighting structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The patent divides the light source into multiple segments by distributing numerous light-emitting diodes along the rear wall instead of using a single point source. This segmentation enables uniform illumination across the interior while avoiding shadowing problems associated with concentrated light sources.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-point (0D) or linear (1D) light source to a distributed two-dimensional arrangement of LEDs across the rear wall. This dimensional expansion allows light to be emitted from multiple locations simultaneously, achieving uniform illumination without increasing structural complexity significantly.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Illumination intensity

If a tubular lamp or widely distributed LED arrangement is used, then shadowing is reduced, but the space requirement increases

Engineering Contradiction:
Improvedistribution of lightVSAvoidfootprint of lighting system
Core Design Contradiction:
Illumination intensityVSArea of stationary object

Solution Approach 1:

The patent applies local quality by concentrating the LED distribution specifically on the rear wall surface rather than spreading lights throughout the entire interior volume. This localized approach achieves good light distribution while minimizing the space occupied by the lighting system itself.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses numerous small LED elements that replicate the light-emitting function across the rear wall surface. Instead of requiring a large tubular lamp, many small LED copies of the light source are distributed across the available surface area, achieving uniform illumination with compact footprint.

Inventive Principle:
Principle #26Copying

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

This approach provides even, shadow-free illumination with a reduced number of lamps and a smaller footprint, ensuring that all interior areas receive adequate light while maintaining efficient light guidance and minimizing losses through total internal reflection and strategic decoupling.

Implementation Method 1

An air gap between the light guide and the protective screen is useful to ensure efficient guiding of the light in the light guide by total internal reflection at its major surfaces.

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Decoupling structures not according to the invention can be indentations in a main surface of the light guide, at which light propagating essentially parallel to the main surface in the light guide is refracted and deflected out of the light guide.

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP2318794B1Refrigerator with interior lighting
Publication Date: 2018.07.18 BSH HAUSGERATE GMBH
  • EP2318794B1 patent drawingFigure 1~3
  • EP2318794B1 patent drawingFigure 4~5

AI summary

An interior lighting of a refrigerator comprises at least one illumination means (11) and a fiber optic (12) for transferring light from the illumination means (11) to the interior space. The fiber optic (12) comprises a transparent flat member (16) that extends along a wall (6) of the interior space, and a plurality of coupling-out structures (17) distributed at the member (16).