Vehicle Headlamp Light Guide Homogenization

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Solution Overview

Problem

Existing light-guiding elements for motor vehicle headlights often produce inhomogeneous light distribution, especially when using light sources with a pronounced main emission direction like LEDs, leading to uneven brightness and increased manufacturing costs due to complex mold designs and burrs.

Innovation Solution

A light-guiding element with a design that redirects incident light through optical structuring elements and fiber-optic rods or grooves, allowing for homogeneous light distribution by pre-homogenizing light within the element, and featuring a smooth or structured decoupling surface, with adjustable parameters like prism structure and cross-sectional diameters to optimize light emission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light-guiding elements with recesses and cutouts are used to distribute light uniformly, then light distribution homogeneity is improved, but manufacturing complexity and cost increase due to burrs and expensive tooling

Engineering Contradiction:
Improvelight distribution homogeneityVSAvoidmanufacturing complexity
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The light-guiding element is segmented into multiple light guide bars with different cross-sections arranged in a fan shape. Each bar acts as an independent light guiding channel, allowing light to be distributed uniformly without requiring complex recesses or cutouts in the mold parting line. This segmentation enables homogeneous light distribution while maintaining manufacturing simplicity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light-guiding element have different cross-sectional areas of light guide bars. The bars are designed with varying cross-sections to optimize light distribution in different zones. This local variation in geometry allows uniform light output without requiring complex mold features that cause manufacturing issues.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If complex mold designs with small recesses and cutouts are used, then light distribution can be controlled, but manufacturing cost and maintenance cost increase

Engineering Contradiction:
Improvelight distribution controlVSAvoidmanufacturing cost
Core Design Contradiction:
Illumination intensityVSEase of manufacture

Solution Approach 1:

The invention controls light distribution by changing geometric parameters of the light guide bars, specifically their cross-sectional areas. By varying the cross-section of each bar in the fan-shaped arrangement, the patent achieves precise light distribution control without requiring complex mold features. This parameter-based control approach simplifies the mold design and reduces manufacturing costs.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If light sources with pronounced main beam direction like LEDs are used, then energy efficiency is improved, but light distribution uniformity deteriorates causing uneven brightness

Engineering Contradiction:
Improveenergy efficiencyVSAvoidlight distribution uniformity
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The focused beam from LED light sources is segmented into multiple light guide bars with different cross-sections. This segmentation distributes the concentrated light from the directional LED into multiple channels, preventing the formation of a single bright spot and achieving uniform light distribution across the output surface while maintaining LED energy efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transforms the one-dimensional focused beam from the LED into a two-dimensional fan-shaped distribution pattern using light guide bars arranged in a fan shape with varying cross-sections. This dimensional transformation effectively disperses the directional light into a uniform two-dimensional light field, maintaining energy efficiency while achieving uniformity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Achieves uniform luminance and compliance with regulatory standards by ensuring no intensity jumps in light distribution, preventing the light source from appearing as a bright spot, and reducing manufacturing complexities and costs.

Implementation Method 1

The optical structuring elements redirect the incident light into the light guide sections or grooves in the connecting element

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

The optical structuring elements redirect the incident light into the light guide sections or grooves in the connecting element

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

light from one or more light sources, such as light-emitting diodes (LEDs), halogen, xenon, or discharge lamps, is coupled into the light-guiding element in the light-in coupling area and then reaches the light-out coupling area

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2592333B1Light guide for a vehicle headlamp
Publication Date: 2020.08.05 ZKW GRP GMBH
  • EP2592333B1 patent drawingFigure 1~2
  • EP2592333B1 patent drawingFigure 3~4
  • EP2592333B1 patent drawingFigure 5~6

AI summary

The invention relates to a light guide element (1) for a lighting unit or a motor vehicle headlight, wherein the light element (1) has at least one light coupling area (2) for coupling light with at least one light source and the light guide element (1) further has at least one light coupling area (3) for coupling the light out, wherein a beam section area (4) is arranged downstream of the light coupling area (2), from which at least one first light guide section (5) and at least one second light guide section (6) extend in directions away from each other and in the area spanned by the light guide sections (5, 6) a light-guiding connecting element (7) is arranged, which transitions into the light coupling area (3) on its side facing away from the light guide sections (5, 6), wherein the light guide sections (5, 6) have optical structuring elements (8) on their side facing away from the light coupling area (3).