Light Guide Redistribution for Homogeneous Multi-Color Illumination

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Solution Overview

Problem

Existing motor vehicle light systems face challenges in achieving homogeneous illumination when combining different light functions, such as white daytime running lights and yellow indicators, due to the placement of LEDs outside the focal point, leading to inefficient optical performance and non-uniform light distribution.

Innovation Solution

A light guide arrangement with a redistribution section that splits and rearranges collimated light bundles from multiple LEDs into partial bundles, ensuring homogeneous illumination by using totally reflecting partial surfaces within the light guide, allowing for the combination of different light functions without losing parallelism and achieving uniform appearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple LEDs are placed at different focal points to generate different light functions, then different light functions can be generated, but homogeneous illumination is compromised and optical efficiency decreases

Engineering Contradiction:
Improvelight function versatilityVSAvoidillumination homogeneity
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The light guide is segmented into distinct functional sections: an entry section for light coupling, a redistribution section with totally reflecting partial surfaces for light rearrangement, and an exit section for light emission. This segmentation allows each section to perform its specific function optimally, resolving the contradiction between versatility and homogeneity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The redistribution section acts as an intermediary between the light sources and the exit surface. It contains totally reflecting partial surfaces that split and rearrange collimated light bundles from multiple LEDs, ensuring homogeneous illumination while maintaining optical efficiency. This intermediary structure enables multiple light functions to be combined without compromising appearance uniformity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If LEDs are placed outside the focal point to simplify structure, then device complexity is reduced, but optical efficiency and beam parallelism are lost

Engineering Contradiction:
Improveoptical system complexityVSAvoidoptical efficiency
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

Light is collimated before entering the light guide in the entry section, ensuring parallel beams are formed in advance. This preliminary collimation action maintains beam parallelism and optical efficiency throughout the light guide, even though LEDs are placed at simplified positions outside the strict focal point.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the optical parameters of light beams through the redistribution section, transforming the spatial distribution of light while maintaining collimation. The totally reflecting partial surfaces alter the path and arrangement of light bundles, preserving parallelism while adapting to simplified LED positioning.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If a common optical system is used for multiple light functions, then device complexity is reduced, but optical efficiency decreases due to multiple light sources

Engineering Contradiction:
Improveoptical system structureVSAvoidoptical efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

A single light guide structure serves multiple light functions (daytime running lights, indicators, turn signals) simultaneously. The common optical system uses a unified entry-redistribution-exit structure that can handle light from multiple LEDs of different colors, achieving multi-functionality without sacrificing optical efficiency through proper light management.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Different regions of the light guide are optimized for specific functions. The entry section handles light coupling from multiple sources, the redistribution section with its totally reflecting partial surfaces manages light arrangement locally, and the exit section provides uniform emission. This local optimization maintains high optical efficiency throughout the common optical system.

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 optical efficiency and homogeneity of illumination on the light exit surface, allowing for the simultaneous generation of multiple light functions with a uniform appearance, comparable to single-function lights, while maintaining the parallelism of light beams.

Implementation Method 1

The redistribution section includes totally reflecting partial surfaces of boundary surfaces of the light guide. The partial surfaces are designed and arranged in the light guide in such a way that they split the at least two collimated light bundles arranged next to one another or one on top of the other into a plurality of collimated partial light bundles

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3461687B1Light guide arrangement for a motor vehicle light and motor vehicle light provided with such a light guide arrangement
Publication Date: 2022.10.26 MARELLI GERMANY GMBH
  • EP3461687B1 patent drawingFigure 1~4c
  • EP3461687B1 patent drawingFigure 5~6
  • EP3461687B1 patent drawing

AI summary

The invention relates to a light guide arrangement of a motor vehicle lamp (2), comprising a plate-shaped light guide (20) which is divided into an inlet section (28), a subsequent redistribution section (30) and a subsequent outlet section (32). Light from two light sources is coupled into the inlet section (28) and collimated, so that at a transition (34) between the inlet section (28) and the redistribution section (30) the light from the light sources is present as two adjacent collimated light beams (A, B). The redistribution section (30) comprises totally reflecting sub-areas (40, 42, 44, 46) which divide the two collimated light beams (A, B) into several collimated partial light beams (A1, A2, B1, B2) and rearrange the partial light beams (A1, A2, B1, B2) so that partial light beams (A1, A2) with light from one light source alternate with partial light beams (B1, B2) with light from the other light source.