Automotive Optical Guide with Catadioptric Screen for Uniform Illumination

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing motor vehicle lighting and signaling devices with optical guides face challenges in maintaining uniform illumination across their length and angle of incidence, with light leakage and inefficient optical distribution, particularly in non-axis viewing positions.

Innovation Solution

Incorporating a screen with orientation means, such as catadioptric reflective patterns, to deflect and redirect light rays escaping from the optical guide back into the guide, enhancing optical efficiency and providing a more uniform and wide angular distribution of light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a light guide is designed to illuminate mainly in the axis of the vehicle to respond to photometric standards, then the photometric performance is improved, but the homogeneous and visually pleasing illuminated appearance when the observer moves away from the longitudinal axis deteriorates

Engineering Contradiction:

Improvephotometric performanceVSAvoidangular distribution of light

Core Design Contradiction:

Illumination intensityVSAdaptability or versatility

Solution Approach 1:

A reflector is introduced as an intermediary element positioned behind the light guide to intercept and redirect light rays that would otherwise escape through the rear face. The reflector redirects these rays at specific angles to achieve both photometric compliance and improved angular distribution for side viewing positions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The reflector is designed with specific geometric features (such as angled surfaces or prismatic structures) that create different reflection characteristics for different regions of the light guide, enabling localized control over light distribution to achieve homogeneous appearance across various viewing angles

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the light guide has a significant length to provide adequate illumination, then the coverage area is improved, but the uniformity of illumination between the first and second end of the guide deteriorates due to decreasing illumination level away from the entry face

Engineering Contradiction:

Improveillumination coverage areaVSAvoiduniformity of illumination

Core Design Contradiction:

Area of stationary objectVSIllumination intensity

Solution Approach 1:

The light guide is designed with spatially varying properties, including regions with different extraction efficiencies or integrated reflective/diffusive elements at specific positions along its length, to compensate for the natural attenuation of light and maintain uniform illumination across the entire length

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Reflective elements are pre-positioned within or behind the light guide to redirect light rays before they escape through the rear face, ensuring that illumination is maintained more uniformly along the entire length of the guide rather than allowing progressive dimming

Inventive Principle:

Principle #10Preliminary action

3Illumination intensity

If reflective elements are arranged on the rear face of the light guide to improve light extraction, then the light diffusion is improved, but the optical efficiency deteriorates due to light leakage through the rear face

Engineering Contradiction:

Improvelight diffusionVSAvoidoptical efficiency

Core Design Contradiction:

Illumination intensityVSLoss of energy

Solution Approach 1:

The reflector converts the harmful effect of light leakage through the rear face into a beneficial effect by intercepting these escaped rays and redirecting them back through the light guide or towards the front face, thereby recovering lost light and improving overall optical efficiency while maintaining diffusion

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 improves the optical efficiency and uniformity of illumination across a wider range of angles, allowing for a more aesthetically pleasing and functional lighting and signaling performance, including side position indicator functions without additional components or photometric degradation.

Implementation Method 1

the light rays emitted by this source are propagate by total reflection along the length of the guide towards its opposite end

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

Part of the light rays propagating in the guide will come out of it via the so-called front face of the guide thanks to the presence of reflective elements arranged on the so-called rear face of the guide

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentEP2476947B1Lighting or signalling device with an optical guide for an automobile vehicle

Publication Date: 2014.10.29 VALEO VISION SA

Figure 1~2
Figure 3~6
Figure 7~9

AI summary

Lighting and/or signaling device (1) of a motor vehicle comprising at least one light source (S) emitting a light beam and at least one optical guide (G) in which said light beam propagates, said optical guide comprising: - a first face forming an exit face (FS) of the light beam, - a second face forming a reflection face (FR) of the light beam, and - a screen (ED) disposed opposite the reflection face (FR) of the light guide (G) and comprising a guidance means (19; 29; 39; 49; 59; 69; 79; 89) deflecting rays escaping from the guide at the level of the reflection face, so as to return them at least partially into the guide, the guidance means comprising catadioptric reflective patterns (11; 61; 71; 81).