Curved Light Guide with Refractive Correction Zone

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Solution Overview

Problem

Light guides with significant curvature in motor vehicle lighting and signaling devices experience a loss of beam quality and homogeneity due to rays encountering guide surfaces at angles greater than the limiting refractive angle, leading to reflection issues and reduced illumination in non-accessible areas.

Innovation Solution

A light guide with a coupling zone and a correction zone of a different refractive index, forming diopters that refract light rays to maintain their trajectory and ensure proper alignment with exit or reflection faces, even in curved sections, thereby preventing unnecessary reflections and maintaining beam quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If light guides with significant curvature are used to reach non-accessible areas, then the ability to illuminate non-accessible areas is improved, but beam quality and homogeneity deteriorate due to rays encountering guide surfaces at angles greater than the limiting refractive angle

Engineering Contradiction:
Improveability to illuminate non-accessible areasVSAvoidbeam quality and homogeneity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent introduces a correction zone with a different refractive index (n2) than the main guide body (n1). This parameter change in refractive index allows rays to be refracted at the diopters, correcting their trajectories to maintain proper alignment with exit or reflection faces despite the guide's curvature, thereby preserving beam quality while enabling illumination of non-accessible areas

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The correction zone acts as an intermediary element between the coupling zone and the exit/reflection faces. This intermediate zone with different refractive index serves as a mediator that refracts light rays to correct trajectory deviations caused by guide curvature, allowing the system to maintain beam quality while achieving curvature adaptability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If light rays propagate through curved guide sections, then the guide can reach non-accessible areas, but rays may encounter guide surfaces at angles greater than the limiting refractive angle causing reflection and loss of illumination

Engineering Contradiction:
Improveguide length and reachVSAvoidillumination intensity and beam homogeneity
Core Design Contradiction:
Length of stationary objectVSIllumination intensity

Solution Approach 1:

By changing the refractive index parameter in the correction zone (n2 different from n1), the patent enables controlled refraction of light rays at the diopters. This parameter change corrects ray trajectories to prevent them from encountering guide surfaces at harmful angles, thereby maintaining illumination intensity and homogeneity over extended guide lengths

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The correction zone with its diopters performs a preliminary anti-action by refracting rays before they can encounter the guide surfaces at angles greater than the limiting refractive angle. This preemptive correction prevents the harmful reflection effect from occurring in the first place, preserving beam quality throughout the curved guide section

Inventive Principle:
Principle #9Preliminary anti-action

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 allows for curved light guides without compromising beam quality or homogeneity, ensuring consistent illumination across the entire length, including non-accessible areas, by using a correction zone with a lower refractive index to refract light rays in alignment with the guide's curvature.

Implementation Method 1

a correction zone (12) for a second refractive index n2 different from the first, said zone forming two diopters (16, 18) with the material of the rest of the guide body (2), at least one of the diopters (16, 18) being configured to refract light rays (14) coming from the coupling zone (6) so that they can reach the at least one of the faces output or reflection (22, 122) despite the curvature of the body

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The light rays emitted by the light sources thus propagate along the guide by successive reflections on its guide surfaces according to the principle of total reflection when the angle of incidence is greater than a limit angle

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2713097B1Light guide with curved profile having an area with correction dioptres
Publication Date: 2015.08.12 VALEO VISION SA
  • EP2713097B1 patent drawingFigure 1
  • EP2713097B1 patent drawingFigure 2~3
  • EP2713097B1 patent drawingFigure 4~5

AI summary

The present invention relates to a curved light guide (2) with a correction zone (12). The correction zone (12) has a refractive index n2 different from the refractive index n1 of the main material of the light guide 2, so as to form two diopters (16, 18). At least one (18) of the diopters (16, 18) is configured to refract the rays (14) propagating in the guide (2) which, in the absence of the correction zone and due to the curvature of the guide (2), would encounter one of the guiding surfaces (7, 8) of the guide (2). The correction zone (12) thus makes it possible to deflect the rays along the curvature of the guide and thereby direct them to the exit or reflection face of the guide. At least one of the two diopters (16, 18; 116; 118; 216, 218), preferably the first diopter (18; 118; 218) encountered by the rays coming from the coupling zone (6; 106; 206), is configured to deflect the rays in the same direction as the curvature of the body.