Automotive Headlight Module With Split Heat Sink Design

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Solution Overview

Problem

Existing motor vehicle headlight light modules are complex and expensive to develop for new applications due to their specific design for predetermined light functions and thermal management issues, particularly in dissipating waste heat from LEDs to prevent overheating.

Innovation Solution

A modular light module design where a printed circuit board with LEDs is clamped between two heat sinks, allowing efficient heat dissipation through convection, and components can be easily replaced to change light functions and intensities without redesigning the entire module, using Al-IMS and FR4 composite materials with AlN inlays for enhanced thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If light modules are designed specifically for predetermined light functions with fixed elements, then light function implementation is precise and reliable, but development complexity and cost increase significantly for new applications

Engineering Contradiction:
Improvelight function implementationVSAvoiddevelopment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The light module is divided into separate functional elements (light source, primary optics, secondary optics, screen elements, reflectors) that can be independently selected and combined. This segmentation allows precise implementation of specific light functions while reducing development complexity for new applications, as elements can be reconfigured without redesigning the entire module.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light module employs universal mounting structures and standardized element interfaces that allow the same module platform to implement multiple different light functions by simply changing the combination of optical elements. This universality reduces development complexity while maintaining reliable light function implementation across different applications.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If light modules are designed to be highly integrated with small volume, then space and weight are reduced, but thermal management becomes increasingly difficult

Engineering Contradiction:
Improvelight module volumeVSAvoidheat dissipation
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

The patent utilizes the third dimension (vertical direction) for heat dissipation by positioning heat-generating LED elements above the heat sink and providing ventilation openings in the housing. This dimensional approach allows efficient thermal management within a compact volume by directing heat flow vertically rather than requiring lateral expansion.

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

Solution Approach 2:

A heat sink is introduced as an intermediary thermal management component between the LED light sources and the environment. The heat sink absorbs heat from the LEDs and transfers it to the surrounding air through convection, enabling effective thermal management in the highly integrated compact design.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If active cooling systems like fans are used to cool LEDs, then heat dissipation efficiency is improved, but cost and operational noise increase

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcooling system complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The cooling system is designed to operate passively without active components like fans. The housing structure itself provides ventilation openings that allow natural convection currents to cool the LEDs, eliminating the need for additional active cooling devices. This self-service approach maintains effective heat dissipation while reducing complexity and noise.

Inventive Principle:
Principle #25Self-service

4Manufacturing precision

If elements in light modules are fixed and cannot be exchanged, then manufacturing precision and reliability are maintained, but adaptability to different applications is reduced

Engineering Contradiction:
Improveelement positioning precisionVSAvoidapplication adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

Elements are pre-configured with standardized mounting features and precise positioning structures during manufacturing. This preliminary preparation of mounting interfaces allows elements to be easily exchanged and reconfigured for different applications while maintaining manufacturing precision and reliable positioning without requiring complex adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary 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

This design enables efficient cooling of LEDs without active cooling, reduces the need for redesigning the light module for different applications, and allows for a compact, highly integrated module with improved thermal management, preventing overheating and functional impairment.

Implementation Method 1

The printed circuit board absorbs and dissipates a large part of the waste heat from the at least one LED

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

the heat transfer between the printed circuit board and the two-part heat sink of the light module is particularly efficient. The waste heat from the at least one LED is transferred over a large area to the heat sink, which can then dissipate it to the environment by means of convection

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3404314B1Light module of a motor vehicle headlight and headlight with such a light module
Publication Date: 2022.02.23 MARELLI GERMANY GMBH
  • EP3404314B1 patent drawingFigure 1
  • EP3404314B1 patent drawingFigure 2
  • EP3404314B1 patent drawingFigure 3

AI summary

The invention relates to a light module (10) of a motor vehicle headlight (108), comprising a first sub-module (36) for generating a dimmed light distribution with a horizontal cut-off line, a second sub-module (38) for illuminating a far area above the cut-off line and for realizing a high-beam distribution, and a projection lens (22) for imaging the light emitted by the two sub-modules (36, 38) as the resulting light distribution of the light module (10) onto a road surface in front of the motor vehicle. Both sub-modules (36, 38) each comprise LEDs (29a; 29b) as light sources. It is proposed that the light module (10) has two separate heat sinks (26a, 26b), each assigned to one of the sub-modules (36, 38), which are separated from each other along a horizontal dividing plane (34).A circuit board (48) for the LEDs (29a) of the first sub-module (36) is clamped between the two heat sinks (26a, 26b) along the horizontal parting plane (34) with the light module (10) mounted.