LED Substrate with Ceramic Insulation Layer

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Solution Overview

Problem

Existing light-emitting diode (LED) substrates face challenges in achieving high heat dissipation capacity with low thermal resistance without compromising insulation reliability and high-humidity reliability, as conventional methods either reduce insulation reliability or increase thermal resistance due to the limitations of dielectric materials used in insulation layers.

Innovation Solution

A substrate configuration with a metal base of predetermined thickness, a top conductor thickness within a specific range, and an insulation layer thickness that meets a specific relation to achieve low total thermal resistance, ensuring efficient heat dissipation while maintaining insulation and high-humidity reliability, involves a metal base with high thermal conductivity, a top conductor partially embedded and exposed within the insulation layer, and a dielectric insulation layer primarily composed of ceramic, which is laminated or embedded to match thermal expansion behaviors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the thickness of the insulation layer is reduced to lower thermal resistance, then heat dissipation capacity is improved, but insulation reliability deteriorates

Engineering Contradiction:
Improvethermal resistanceVSAvoidinsulation reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent uses a composite structure consisting of a metal base with high thermal conductivity and a ceramic insulation layer with high breakdown voltage properties. This combination allows the insulation layer to maintain high reliability even at reduced thickness, as the ceramic material provides superior electrical insulation compared to conventional dielectric materials.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameter of the insulation layer from conventional dielectric materials to ceramic materials with high breakdown voltage. This parameter change enables the insulation layer to withstand high electric fields even when thinner, thus maintaining insulation reliability while reducing thermal resistance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the thickness of the insulation layer is increased to improve insulation reliability, then electrical insulation is enhanced, but thermal resistance increases and heat dissipation capacity deteriorates

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidthermal resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent employs a composite structure where the ceramic insulation layer provides both electrical insulation and thermal management. The ceramic material's unique properties allow it to offer high breakdown voltage for insulation reliability while simultaneously providing better thermal conductivity compared to conventional dielectric materials, thus not increasing thermal resistance significantly.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent applies different material properties to different functional requirements: the metal base provides thermal conduction, while the ceramic insulation layer provides electrical insulation with improved thermal properties. This local quality differentiation optimizes both insulation reliability and heat dissipation capacity.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If the thickness of the metal base is increased to improve heat dissipation, then thermal conductivity is enhanced, but differences in thermal expansion behavior between materials increase causing fissures

Engineering Contradiction:
Improveheat dissipation capacityVSAvoidhigh-humidity reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the material parameter of the insulation layer to ceramic materials that have thermal expansion coefficients matched to the metal base. This parameter matching reduces thermal stress and prevents fissure formation, allowing the metal base thickness to be increased for improved heat dissipation without compromising reliability.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If conventional dielectric materials are used in the insulation layer, then manufacturing is simplified, but thermal conductivity remains low creating a bottleneck in heat conduction

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidthermal conductivity
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent replaces conventional dielectric materials with ceramic materials in the insulation layer. Ceramic materials provide superior thermal conductivity while maintaining good manufacturability through established ceramic processing techniques such as screen printing and firing, thus resolving the contradiction between manufacturing simplicity and thermal conductivity.

Inventive Principle:
Principle #40Composite materials

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 enables effective heat dissipation with reduced thermal resistance, preventing LED temperature rise and maintaining insulation and high-humidity reliability, as demonstrated by specific thickness relationships and manufacturing methods such as gel-casting and doctor blade techniques.

Implementation Method 1

a metal base 1 with a thickness Tm of not less than 100 micrometers... a substrate for a light-emitting diode which can show a high heat dissipation capacity by achieving a low thermal resistance

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

an insulation layer 2 which comprises a dielectric material that mainly contains a ceramic... to electrically insulate the metal base 1 and the top conductor 3

Methodology Applied
Scientific EffectDielectric insulation: Dielectric

Implementation Method 3

a top conductor 3 which is at least partially embedded within the insulation layer 2... for an electrical connection with a light-emitting diode

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2919287B1Substrate for light emitting diodes
Publication Date: 2019.12.25 NGK INSULATORS LTD
  • EP2919287B1 patent drawingFigure 1
  • EP2919287B1 patent drawingFigure 2
  • EP2919287B1 patent drawingFigure 3~4

AI summary

A substrate for a light-emitting diode comprising a metal base with a thickness of a predetermined value or more is constituted so that the thickness of a top conductor for an electrical connection with a light-emitting diode (LED) in a predetermined range falls within a predetermined range and the thickness of an insulation layer which electrically insulates the metal base and the top conductor and the thickness of the top conductor meet a predetermined relation. Thereby, a substrate for a light-emitting diode which can show a high heat dissipation capacity by achieving a low thermal resistance as the total thermal resistance of the whole substrate without reducing insulation reliability and high-humidity reliability of the substrate is provided.