OLED Encapsulation Layer with Composite Fillers

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Solution Overview

Problem

Organic light-emitting diodes (OLEDs) face issues with durability and electric conductivity due to oxidation from water and physical impact, leading to degradation and failure, especially when heat is not effectively managed.

Innovation Solution

An encapsulating layer comprising a stack of a water barrier film, glass cap, and metal foil is applied to the entire top surface of the OLED, providing excellent water and oxygen barrier effects while allowing for thermal conductivity and electrical connectivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an encapsulating layer is applied to prevent water and oxygen penetration, then durability is improved, but heat dissipation is hindered leading to device failure

Engineering Contradiction:
ImprovedurabilityVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The encapsulating layer uses a composite structure combining an epoxy resin base material with inorganic filler particles (such as氧化铝, 氧化镁, or 氮化硼). This composite structure provides both effective water and oxygen barrier properties while the inorganic filler particles with high thermal conductivity enable efficient heat dissipation, resolving the contradiction between durability improvement and heat dissipation capability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the encapsulating layer by controlling the type and content of inorganic fillers (30-70 wt%), adjusting curing agents, and optimizing molecular weight of the epoxy resin. These parameter changes allow the material to simultaneously achieve low water vapor transmission rate (≤10^-6 g/m²/day) and high thermal conductivity (≥1.0 W/mK), thus improving durability while maintaining heat dissipation

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional epoxy resin encapsulation is used, then ease of manufacture is improved, but heat generated during operation causes diode deterioration and failure

Engineering Contradiction:
Improveease of manufactureVSAvoiddevice stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The encapsulating layer uses a composite structure combining an epoxy resin base material with inorganic filler particles (such as氧化铝, 氧化镁, or 氮化硼). This composite structure provides both effective water and oxygen barrier properties while the inorganic filler particles with high thermal conductivity enable efficient heat dissipation, resolving the contradiction between durability improvement and heat dissipation capability

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent modifies the physical and chemical parameters of the encapsulating layer by controlling the type and content of inorganic fillers (30-70 wt%), adjusting curing agents, and optimizing molecular weight of the epoxy resin. These parameter changes allow the material to simultaneously achieve low water vapor transmission rate (≤10^-6 g/m²/day) and high thermal conductivity (≥1.0 W/mK), thus improving durability while maintaining heat dissipation

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the encapsulating layer is entirely in contact with the diode, then protection against oxidation is improved, but electrical conductivity may be affected

Engineering Contradiction:
Improveprotection against oxidationVSAvoidelectrical conductivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The encapsulating layer is designed with non-uniform distribution of inorganic filler particles, creating regions with different properties. Areas closer to the diode interface have optimized filler content for protection, while other regions maintain better electrical properties. This local quality variation allows the encapsulating layer to provide comprehensive oxidation protection while minimizing negative impact on electrical conductivity

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent modifies the physical and chemical parameters of the encapsulating layer by controlling the type and content of inorganic fillers (30-70 wt%), adjusting curing agents, and optimizing molecular weight of the epoxy resin. These parameter changes allow the material to simultaneously achieve low water vapor transmission rate (≤10^-6 g/m²/day) and high thermal conductivity (≥1.0 W/mK), thus improving durability while maintaining heat dissipation

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

The encapsulating layer significantly enhances the reliability of OLEDs by preventing contraction and deterioration, maintaining device integrity under high temperature and humidity conditions and during prolonged operation, with observed reliability periods exceeding 180 hours and effective heat dissipation.

Implementation Method 1

an encapsulating layer which has a structure in which at least two of a water barrier film, a glass cap, a metal foil and a conductive film are stacked

Methodology Applied
Scientific EffectWater barrier: Permeation

Implementation Method 2

the encapsulating layer is entirely in contact with the diode... having excellent water and oxygen barrier effects... effective heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP2579353B1Organic light-emitting device comprising an encapsulation structure
Publication Date: 2018.09.05 LG DISPLAY CO LTD
  • EP2579353B1 patent drawingFigure 1~2
  • EP2579353B1 patent drawingFigure 3
  • EP2579353B1 patent drawingFigure 4

AI summary

Provided is an organic light emitting diode including an organic light-emitting part including a first electrode, an organic material layer having a light-emitting layer, and a second electrode, and an encapsulating layer included on an entire top surface of the organic light-emitting part. Here, the encapsulating layer has a structure in which at least two of a water barrier film, a glass cap, a metal foil and a conductive film are stacked. Accordingly, the diode may have excellent water and oxygen barrier effects, and deterioration of the diode or running failure may be prevented.