Thermal Pyrolytic Graphite LED Heat Spreader for High Power Dissipation

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Solution Overview

Problem

Conventional thermal management systems for light emitting diodes (LEDs) face limitations in maximum power loading and design options due to their thermal conductivity, often requiring increased size, weight, and complexity, and are unreliable for high-power applications.

Innovation Solution

A thermal management assembly utilizing thermal pyrolytic graphite with a metal-based interlayer between the graphite core and surrounding substrates, providing low thermal interface resistance and enabling efficient heat dissipation without the need for forced air or liquid cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional copper or aluminum thermal management products are used, then thermal conductivity is achieved (120-400 W/m-K), but the system is limited in maximum power loading and requires increased size and weight

Engineering Contradiction:
Improvemaximum power loadingVSAvoidweight of thermal management system
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The patent uses thermal pyrolytic graphite (TPG) composite material with metal encapsulation to create a hybrid thermal management system. The TPG provides superior thermal conductivity (greater than 1500 W/m-K) while the metal encapsulation provides structural support and ease of integration, achieving both high power loading capability and reduced weight compared to pure metal systems

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If conventional copper or aluminum thermal management products are used, then thermal conductivity is achieved, but design options are limited and cross-section of heat paths must be increased

Engineering Contradiction:
Improvedesign optionsVSAvoidcross-section of heat paths
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The TPG-metal composite enables new design configurations including thin-film heat spreaders, flexible thermal interfaces, and compact heat sinks that were not feasible with conventional metals. The anisotropic thermal conductivity of TPG allows optimization of heat flow paths in specific directions without increasing overall component volume

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies TPG material strategically at critical thermal interface locations where its superior thermal conductivity provides maximum benefit, such as between the LED chip and heat sink, or in heat spreader layers. This localized application optimizes thermal management performance without requiring complete redesign of entire thermal paths

Inventive Principle:
Principle #3Local quality

3Temperature

If forced air cooling or liquid cooling is installed to improve heat dissipation, then heat dissipation area is enlarged, but system complexity and reliability are reduced

Engineering Contradiction:
Improveheat dissipation capabilityVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The TPG-based thermal management system provides passive cooling through its inherent high thermal conductivity, eliminating the need for active cooling components such as fans, pumps, or heat exchangers. The material's superior thermal properties enable sufficient heat dissipation through natural convection and radiation alone, achieving self-sufficient thermal management

Inventive Principle:
Principle #25Self-service

4Power

If thermal pyrolytic graphite is used, then thermal conductivity is improved (greater than 1500 W/m-K), but manufacturing complexity increases due to encapsulation requirements

Engineering Contradiction:
Improvethermal conductivityVSAvoidmanufacturing process
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent extracts only the essential function of TPG (thermal conduction) and encapsulates it in a simple metal housing that provides structural support and ease of handling. The encapsulation process is simplified to basic forming and attachment operations, avoiding complex manufacturing steps while preserving the thermal performance benefits of TPG

Inventive Principle:
Principle #2Taking out (Extraction)

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 thermal management assembly achieves a significant reduction in thermal resistance, allowing for increased power loading and extended runtime of LEDs without overheating, and eliminates the need for additional cooling systems.

Implementation Method 1

Thermal pyrolytic graphite (TPG), with its metal encapsulated composites, is an advanced thermal management material serving military and aerospace industries for over a decade. Thermal pyrolytic graphite is formed via a two-step process that provides well-aligned graphene planes to provide a material with superior thermal conductivity (e.g., greater than 1500 W/m-K)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

Such thermal management products are commonly used for extracting heat from a heat source and dissipating the heat into surroundings

Methodology Applied
Scientific EffectThermal radiation: Thermal Radiation

Implementation Method 3

For conventional heat spreaders or heat sinks for LED systems, attempts to provide good thermal management have included increasing cross-section of heat paths, enlarging heat dissipation area, and/or installing forced air cooling or liquid cooling

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3295081B1Light emitting diode assembly using thermal pyrolytic graphite for thermal management
Publication Date: 2020.07.08 MOMENTIVE PERFORMANCE MATERIALS QUARTZ INC
  • EP3295081B1 patent drawingFigure 1
  • EP3295081B1 patent drawingFigure 2~3
  • EP3295081B1 patent drawingFigure 4

AI summary

A light emitting diode assembly comprising such thermal management assembly is shown and described herein. The light emitting diode assembly may comprise a light emitting diode in thermal contact with a heat spreader. The heat spreader may comprise a core and/or fins. The core and/or fins comprise a thermal pyrolytic graphite material. The thermal management assembly comprising the core and/or fins can dissipate heat from the light emitting diode.