LED Carrier Assembly Thermal Management via Composite PCB

Solution Overview

Problem

High-power LEDs face efficiency reduction due to heat management issues, as some materials like Aluminium Nitride, used for thermal conductivity and electrical isolation, are expensive and difficult to assemble due to their brittle nature.

Innovation Solution

An LED carrier assembly is designed with a silicon submount, a thermally conductive and electrically isolating middle layer, and a metal core PCB, utilizing eutectic bonding and soldering layers for efficient thermal and electrical management, along with a heat sink layer for effective heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If Aluminium Nitride is used on LED carrier for thermal conductivity and electrical isolation, then thermal management efficiency is improved, but manufacturing cost increases and assembly difficulty increases due to brittle characteristics

Engineering Contradiction:

Improvethermal management efficiencyVSAvoidassembly difficulty

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces expensive and difficult-to-assemble AlN with a cost-effective alternative structure consisting of a metal core PCB with thermally conductive epoxy adhesive. This substitution uses more economical materials while achieving the required thermal management function, directly addressing the high manufacturing cost and assembly difficulty associated with AlN carriers.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent employs a composite structure combining metal core PCB with thermally conductive epoxy adhesive layer. This composite approach integrates the high thermal conductivity of metal (copper or aluminum core) with the electrical isolation and thermal bonding capabilities of the epoxy adhesive, achieving both thermal management and electrical isolation functions while avoiding the brittleness and assembly difficulties of AlN.

Inventive Principle:

Principle #40Composite materials

2Temperature

If Aluminium Nitride is used on LED carrier for thermal conductivity and electrical isolation, then thermal management efficiency is improved, but manufacturing cost increases

Engineering Contradiction:

Improvethermal management efficiencyVSAvoidmanufacturing cost

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces expensive and difficult-to-assemble AlN with a cost-effective alternative structure consisting of a metal core PCB with thermally conductive epoxy adhesive. This substitution uses more economical materials while achieving the required thermal management function, directly addressing the high manufacturing cost and assembly difficulty associated with AlN carriers.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent employs a composite structure combining metal core PCB with thermally conductive epoxy adhesive layer. This composite approach integrates the high thermal conductivity of metal (copper or aluminum core) with the electrical isolation and thermal bonding capabilities of the epoxy adhesive, achieving both thermal management and electrical isolation functions while avoiding the brittleness and assembly difficulties of AlN.

Inventive Principle:

Principle #40Composite materials

3Power

If high power is used in LED package, then light output is improved, but heat generation increases reducing LED efficiency

Engineering Contradiction:

Improvelight outputVSAvoidheat generation

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent introduces a thermally conductive epoxy adhesive layer as an intermediary between the LED chip and the metal core PCB. This intermediary material facilitates efficient heat transfer from the LED chip to the heat-sinking PCB structure, enabling effective thermal management of high-power LEDs and maintaining LED efficiency despite high power operation and associated heat generation.

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 provides efficient thermal management and electrical isolation, reducing the cost and complexity of assembly while maintaining high thermal conductivity, thus enhancing the efficiency and reliability of high-power LEDs.

Implementation Method 1

a middle layer that is thermally conductive and electrically isolating disposed below the silicon submount

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

utilizing eutectic bonding and soldering layers for efficient thermal and electrical management

Methodology Applied

Scientific EffectEutectic bonding: Welding

Implementation Method 3

utilizing eutectic bonding and soldering layers for efficient thermal and electrical management

Methodology Applied

Scientific EffectSoldering: Soldering

Implementation Method 4

along with a heat sink layer for effective heat dissipation

Methodology Applied

Scientific EffectHeat dissipation: Heat Sink

Data Source

PatentUS9006770B2Light emitting diode carrier

Publication Date: 2015.04.14 ENNOSTAR CORP

AI summary

A light emitting diode (LED) carrier assembly includes an LED die mounted on a silicon submount, a middle layer that is thermally conductive and electrically isolating disposed below the silicon submount, and a printed circuit board (PCB) disposed below the middle layer. The middle layer is bonded with the silicon submount and the PCB.