Corrected Elliptical Reflector for Motor Vehicle Headlamp

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Solution Overview

Problem

Existing motor vehicle headlamp lighting modules suffer from light losses and reduced efficiency due to the use of transparent blades, which cause refraction and create dark zones between beams, and the high cost and heat issues associated with materials like glass and plastic in reflective coatings.

Innovation Solution

A lighting module design featuring a blade with a planar edge aligned with the optical axis, covered with a reflective coating, and a corrected reflective surface calculated to compensate for refraction, optimizing the beam path and reducing losses by using a thin, efficient folder that avoids dark zones between 'main' and 'dipped' beams.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If a transparent blade is used to create a reflective folder, then the folder can be extremely thin and avoid dark zones between beams, but the blade refracts light rays causing loss of efficiency and quality

Engineering Contradiction:
Improvethickness of folderVSAvoidlight efficiency
Core Design Contradiction:
Length of moving objectVSLoss of energy

Solution Approach 1:

The invention extracts the refractive function from the transparent blade by removing or minimizing the blade material between the reflector and lens. The reflective folder is created directly on the reflector surface or using a minimal-thickness substrate, eliminating the refraction problem while maintaining the thin-folder benefit for avoiding dark zones between dipped and road beams.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies different properties to different parts of the optical system: the reflective folder area uses highly reflective coating with minimal substrate thickness to prevent refraction, while other areas may use transparent materials where refraction is less critical. This local differentiation optimizes both the thin-folder requirement and light efficiency.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If glass is used for the transparent blade support, then refraction losses are reduced, but manufacturing cost increases significantly

Engineering Contradiction:
Improvelight refraction lossVSAvoidmanufacturing cost
Core Design Contradiction:
Loss of energyVSEase of manufacture

Solution Approach 1:

The invention extracts the support function from a thick glass blade and replaces it with a thin substrate that can be glass, plastic, or metal. By minimizing the thickness of the support material, refraction losses are reduced while allowing the use of cheaper materials like plastic or thin metal foils instead of thick glass.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention allows the use of cheaper materials (plastic, thin metal) for the blade support instead of expensive glass, accepting that these materials may have shorter lifespan or lower durability. This trades material cost for manufacturing ease and reduced refraction losses through minimal thickness.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Ease of manufacture

If plastic material is used for the transparent blade, then manufacturing cost is reduced, but heat resistance becomes problematic due to lens concentration

Engineering Contradiction:
Improvemanufacturing costVSAvoidheat resistance
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The invention extracts the heat-resistant support function from the transparent blade material itself and provides it separately through a dedicated heat sink or cooling structure. This allows the blade to use cheap plastic material while the separate cooling system handles the heat dissipation challenge.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces an intermediary cooling system (heat sink, thermal management structure) between the lens and the plastic blade. This intermediary component absorbs and dissipates the concentrated heat from the lens, protecting the plastic blade from overheating while allowing the use of cost-effective plastic material.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 lighting performance by minimizing light losses and maintaining high intensity, while also reducing material costs and heat issues through the use of a thin, efficient reflective coating and optimized beam path correction.

Implementation Method 1

The edge or upper surface of the transparent blade is generally flat and aligned with the optical axis and covered with a reflective coating. The reflective coating on the upper edge of the transparent blade consists for example of an aluminum deposit... The reflective coating constitutes a 'folder' capable of 'folding' by reflection the rays coming from the upper reflector

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The blade serving as the support for the reflective coating, however, has the drawback of having a refractive index greater than 1 and, therefore, of refracting the rays coming from the lower reflector. The use of a transparent support blade therefore generates a slight deviation of the rays which would otherwise pass through the second focal point

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

the corrected reflective surface is such that it transforms a spherical wave surface in the air coming from a given point of the light source into a spherical wave surface in the material of the blade centered approximately at the second focus

Methodology Applied
Scientific EffectRefraction compensation: Refraction

Data Source

PatentEP2410237B1Reflector of the corrected elliptical type
Publication Date: 2017.04.19 VALEO VISION SA
  • EP2410237B1 patent drawingFigure 1
  • EP2410237B1 patent drawingFigure 2~3
  • EP2410237B1 patent drawingFigure 4~5

AI summary

The module has a dioptric element (4) provided with an optical axis (2), and receiving luminous rays reflected by reflectors (10). A transparent material bar (6) is arranged between the reflectors and the dioptric element. A reflective surface is formed such that the rays emitted by a light source and originated from a combustor (22) passes through another combustor (24) after reflexion on the reflective surface and refraction at the passage in the bar. An independent claim is also included for a method for optimizing a lighting module of a headlamp of a motor vehicle.