Vehicle Headlamp Reflector Design for Uniform Light Distribution

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Solution Overview

Problem

Vehicle headlamps with semiconductor light emitting elements experience vertical dark stripes due to insufficient light distribution between elements, despite the use of reflectors, as existing reflector shapes and configurations fail to adequately address this issue.

Innovation Solution

The vehicle headlamp design incorporates a plurality of semiconductor light emitting elements with first reflectors having flat reflection surfaces, with varying intervals and angles between them, and additional second reflectors with longer upper and shorter lower reflection surfaces, along with a projection lens with a curvature that decreases towards the outer circumference, to enhance light distribution and prevent dark stripes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a plurality of semiconductor light emitting elements are arranged in a horizontal direction and projected via a projection lens, then the light source structure is simple, but vertical dark stripes occur in the light distribution pattern due to non-light regions between elements

Engineering Contradiction:
Improvelight source structureVSAvoidlight distribution uniformity
Core Design Contradiction:
Device complexityVSIllumination intensity

Solution Approach 1:

A reflector is introduced as an intermediary component between the semiconductor light emitting elements and the projection lens. The reflector captures light from multiple elements and redirects it to fill the dark stripe regions, mediating between the simple array structure and the uniform illumination requirement

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The reflector is designed with a specific asymmetric shape where the left reflection surface has a different area than the right reflection surface. This local differentiation allows targeted illumination of specific dark stripe regions, with each surface area optimized for its corresponding position to achieve uniform overall illumination

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If reflectors are provided in the left and right sides of semiconductor light emitting elements, then some light distribution is improved, but the light distributed in the boundary region is insufficient and vertical dark stripes are not sufficiently prevented

Engineering Contradiction:
Improvelight distribution in boundary regionVSAvoidreflector configuration
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The reflector design changes the parameter of reflection surface area asymmetrically, with the left reflection surface having a different area than the right reflection surface. This parameter modification optimizes light distribution to specific regions, achieving better boundary illumination without requiring multiple separate reflector components

Inventive Principle:
Principle #35Parameter changes

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 configuration improves light distribution patterns by preventing vertical dark stripes and increasing light efficiency, ensuring a more uniform and effective illumination pattern.

Implementation Method 1

a plurality of semiconductor light emitting elements 15 which are arranged in a left and right direction and each has a light emitting surface

Methodology Applied
Scientific EffectLight Emitting Diode: Light Emitting Diode

Implementation Method 2

a first right reflector 18r on a right side of the light emitting surface; and a first left reflector 18l on a left side of the light emitting surface, wherein a reflection surface of the first right reflector and a reflection surface of the first left reflector are formed as a flat surface

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a projection lens 12 which projects light emitted from the semiconductor light emitting elements toward a outside region

Methodology Applied
Scientific EffectLens focusing: Lens

Data Source

PatentEP2746646B1Vehicle headlamp
Publication Date: 2020.05.06 KOITO MFG CO LTD
  • EP2746646B1 patent drawingFigure 1~2
  • EP2746646B1 patent drawingFigure 3
  • EP2746646B1 patent drawingFigure 4~5

AI summary

There is provided a vehicle headlamp including: plural semiconductor light emitting elements (15) which are arranged in a left and right direction and each has a light emitting surface; plural first reflectors each provided for corresponding one of the semiconductor light emitting elements (15), each including: a first upper reflector (18u) on an upper side of the light emitting surface; a first lower reflector (18d) on a lower side of the light emitting surface; a first right reflector (18r) on a right side of the light emitting surface; and a first left reflector (18l) on a left side of the light emitting surface, a projection lens which projects light emitted from the semiconductor light emitting elements (15) toward a outside region. A reflection surface of the first right reflector (18r) and a reflection surface of the first left reflector (181) are formed as a flat surface.