Bent Light Guide Junction Redirects Stray Rays

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Solution Overview

Problem

Existing motor vehicle light devices experience significant light ray losses and parasitic rays at the junction between light-guiding parts, leading to altered photometry and unsightly light emission.

Innovation Solution

A motor vehicle light device design featuring a main guide part and a secondary guide part arranged such that the secondary part extends rearward from the junction zone, with a reflection portion forming an angle less than 270°, minimizing light leakage and redirecting stray rays back into the secondary guide part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If light-guiding parts are connected at junctions, then light transmission between parts is achieved, but light ray losses and parasitic rays occur at the junctions

Engineering Contradiction:
Improvelight transmission efficiencyVSAvoidlight ray losses at junctions
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention converts the harmful effect of light rays escaping at junctions into a beneficial effect by providing a reflection portion that redirects these stray rays back into the light guide. The reflection portion uses the previously lost light rays and redirects them usefully, transforming the harmful junction leakage into a beneficial light redirection mechanism that improves overall light transmission efficiency.

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

2Use of energy by moving object

If light-guiding parts are connected at junctions, then light transmission between parts is achieved, but parasitic rays alter photometry and create unsightly light emission

Engineering Contradiction:
Improvelight transmission between partsVSAvoidparasitic rays altering photometry
Core Design Contradiction:
Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The reflection portion captures parasitic rays that would otherwise escape and alter photometry, redirecting them back into the light guide structure. This converts the harmful parasitic rays into useful light that continues toward its intended destination, thereby preserving photometric accuracy and eliminating unsightly light emission patterns.

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

Solution Approach 2:

The reflection portion acts as an intermediary element at the junction between light-guiding parts. It mediates the interaction between escaping light rays and the light guide structure, redirecting the rays back into the guide rather than allowing them to escape directly. This intermediary reflection surface prevents parasitic rays from altering photometry while maintaining efficient light transmission.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the secondary guide part extends forward from the junction zone, then light rays are guided forward, but more stray rays escape from the light guide

Engineering Contradiction:
Improvelight guidance directionVSAvoidstray rays escaping
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

Instead of extending the secondary guide part forward from the junction zone (conventional approach), the invention inverts the arrangement by extending it rearward. This inverted configuration, combined with the reflection portion, redirects stray rays back into the guide rather than allowing them to escape forward, thereby reducing energy loss while maintaining proper light guidance.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design reduces light ray losses and enhances light distribution by redirecting stray rays, improving the photometry and aesthetic appearance of the light beam, while allowing for a more efficient illumination pattern and reduced risk of parasitic light emission.

Implementation Method 1

a second part of the light rays passing through the entrance diopter are reflected inside said secondary guide part

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3045804B1Luminous device for automobile vehicle comprising a light guide with a portion bent towards the rear
Publication Date: 2019.06.26 VALEO ILUMINACION SA
  • EP3045804B1 patent drawingFigure 1~3
  • EP3045804B1 patent drawingFigure 4
  • EP3045804B1 patent drawingFigure 5

AI summary

The present invention relates to a light guide 1 of a vehicle lighting device, comprising: - a main light guiding part 10 comprising an upstream portion 14 delimited by an input diopter 12 intended to receive light rays from a light source and a downstream portion 17 delimited by a main output diopter 18 the main guiding part being arranged so that a first part of the light rays R1 passing through the input diopter are guided to the main output diopter, - a secondary light guiding part 20 joined to said main guiding part 10 in a junction zone 22 in which said secondary guiding part 20 extends on the side of the upstream portion 14 of the main guiding part 10.