Vehicle Light Guide Defocusing Element Homogeneous Illumination

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing light guides for vehicles suffer from undesirable brightness maxima due to focusing of light, leading to non-homogeneous illumination, especially when using RGB-light diodes for white light generation.

Innovation Solution

A defocusing element is introduced between the light coupling surface and the main section, comprising a widened part with a conical shape and a straight cylindrical part, which disperses and mixes light beams before they reach the main section, preventing luminance maxima and maintaining radiation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the section for the coupling-in of light is shaped to focus light to form a focal line, then the illumination homogeneity in the main section is improved, but brightness maxima occur within the main section of the light guide

Engineering Contradiction:

Improveillumination homogeneityVSAvoidbrightness maxima

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

Instead of focusing light to achieve homogeneous illumination, the patent inverts the approach by using a defocusing element that deliberately spreads and mixes light beams. The defocusing element with its widened part and straight part creates the opposite effect of focusing, thereby avoiding brightness maxima while still achieving homogeneous illumination through light mixing.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The defocusing element acts as an intermediary component between the light coupling surface and the main section. This intermediate element processes the light by defocusing and mixing it before it enters the main section, thereby preventing the formation of brightness maxima while maintaining illumination homogeneity.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If a defocusing element is introduced to avoid brightness maxima, then homogeneous illumination is achieved, but the radiation characteristic of the light guide in the main section may be influenced

Engineering Contradiction:

Improveillumination homogeneityVSAvoidradiation characteristic

Core Design Contradiction:

Illumination intensityVSReliability

Solution Approach 1:

The defocusing element is designed with different local zones: a widened part for initial light spreading and a straight part for guiding and mixing. Each local region performs a specific function - the widened part defocuses light to avoid maxima, while the straight part maintains proper light direction and mixing, thereby preserving the overall radiation characteristic.

Inventive Principle:

Principle #3Local quality

3Use of energy by moving object

If the section for the coupling-in of light is made ellipsoidal or lens-shaped, then light coupling efficiency is improved, but focusing effects cause undesirable brightness maxima

Engineering Contradiction:

Improvelight coupling efficiencyVSAvoidbrightness maxima

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The defocusing element is segmented into two functional parts: a widened part that handles the initial light coupling and defocusing, and a straight part that handles light guiding and mixing. This segmentation allows efficient light coupling while preventing focusing effects that would cause brightness maxima.

Inventive Principle:

Principle #1Segmentation

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 solution achieves homogeneous illumination in the light guide without photometric or efficiency losses, allowing optimal mixing of RGB colors and reducing manufacturing costs, while avoiding high luminance values in both the coupling-in and main sections.

Implementation Method 1

the defocusing element has a defocusing, i.e. light dispersive outer surface which achieves an improved swirling and spatial mixing of the light beams

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS8956026B2Light guides for vehicles

Publication Date: 2015.02.17 HELLA GMBH & CO KGAA

AI summary

A light guide for vehicles includes a light coupling section for the coupling of light into a first end and/or a second end of the light guide, with a main section having a front side for the coupling out of light and a back extending between the first end and the second end of the light guide and comprising elements for coupling-out for the deflection of the coupled-in light toward the front side, wherein the section for the coupling-in of light is embodied as a defocusing element situated between a surface coupling the light in and the main section.