Elliptical Light Guide for Motor Vehicle Lighting Intensity

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing motor vehicle lighting and signaling systems face challenges in maintaining high light intensity and compact design, particularly when integrating multiple functions like scrolling direction indicators and daytime running lights, as the use of cylindrical light guides can reduce luminous flux intensity.

Innovation Solution

An optical device featuring a first sheet light guide for scrolling direction indicators and a second tubular light guide with an elliptical cross section for daytime running lights, where the tubular guide is arranged to propagate light rays from both sources, increasing perceived light intensity by approximately 30% compared to conventional circular cross-section designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a cylindrical light guide is used to integrate multiple light functions, then the device size is reduced, but the luminous flux intensity is reduced

Engineering Contradiction:
Improvedevice sizeVSAvoidluminous flux intensity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent applies asymmetry by changing the light guide cross-section from a symmetric circular shape to an asymmetric elliptical shape. This allows the minor axis to be aligned with the light propagation direction, reducing the optical path length and increasing light intensity while maintaining the compact integrated structure for multiple light functions

Inventive Principle:
Principle #4Asymmetry

2Volume of moving object

If multiple light functions are integrated in the same optical device, then the space utilization is improved, but the light intensity of individual functions is reduced

Engineering Contradiction:
Improvespace utilizationVSAvoidlight intensity
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The patent applies local quality by optimizing the light guide geometry specifically for the scrolling direction indicator function. The elliptical cross-section with the minor axis aligned to the light propagation path creates a localized optimization that enhances light intensity for the daytime running light function while maintaining the integrated structure for multiple functions

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 light intensity and reduces system size by optimizing the arrangement of light guides, achieving a more efficient and compact lighting system for motor vehicles.

Implementation Method 1

The first guide is configured to propagate the light rays coming from a first light source towards its exit face

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3150907B1Optical device and signalling and/or lighting system for a motor vehicle
Publication Date: 2018.11.14 VALEO ILUMINACION SA
  • EP3150907B1 patent drawingFigure 1~4

AI summary

The invention provides an optical device (100) comprising at least one first light guide (110) having an output face (112). The first guide is configured to propagate light rays from a first light source towards its output face. The output face is positioned opposite a coupling zone (121) which forms part of the lateral surface of a second, generally tubular, light guide (120) of the device. The invention improves the transmission of light emitted by the output face of the first guide through the second guide. In particular, the invention provides the implementation of a lighting device for a motor vehicle integrating two lighting functions.