Scattering Layer for OLEDs Using Liquefied Glass

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional scattering layers in OLEDs face issues such as degradation upon contact with water and oxygen, low refractive index, and surface roughness leading to short circuits and encapsulation failures, which hinder efficient extraction of electromagnetic radiation.

Innovation Solution

A method involving the application of scattering centers onto a carrier, followed by liquefaction of glass to form a smooth scattering layer with adjusted scattering cross-section and refractive index, ensuring a continuous glass connection without gaps, thereby reducing total internal reflection and enhancing radiation extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If organic scattering layers are used in OLEDs, then the refractive index is low (n~1.475), but the stability of the OLED is reduced due to aging and degradation upon contact with water and oxygen

Engineering Contradiction:

Improverefractive indexVSAvoidstability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The patent uses a composite material consisting of inorganic scattering centers (such as glass beads or ceramic particles) embedded in an organic matrix. This composite structure combines the high refractive index of inorganic materials with the processability of organic materials, achieving both optical performance and stability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material composition parameters by replacing pure organic scattering layers with a hybrid structure containing inorganic scattering centers. This parameter change increases the refractive index from ~1.475 to higher values while improving stability against water and oxygen degradation.

Inventive Principle:

Principle #35Parameter changes

2Ease of manufacture

If scattering centers are embedded in organic matrix, then the scattering layer can be produced, but the surface roughness leads to formation of spikes that cause short circuits and encapsulation failures

Engineering Contradiction:

Improveproduction capabilityVSAvoidsurface smoothness

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies a thin encapsulation layer or planarization layer over the scattering layer to smooth out surface irregularities. This thin film approach covers the spikes and roughness without significantly affecting the overall device structure or adding excessive complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces an intermediary layer (such as a planarization layer or encapsulation layer) between the scattering layer and the electrodes/encapsulation. This intermediary layer mediates the surface roughness issue by providing a smooth interface that prevents short circuits while allowing the scattering function to remain effective.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If conventional scattering layers are used, then electromagnetic radiation can be extracted, but total internal reflection reduces extraction efficiency to only ~20%

Engineering Contradiction:

Improveradiation extraction efficiencyVSAvoidrefractive index

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The patent employs composite materials with higher refractive index inorganic scattering centers to reduce total internal reflection at the interfaces. The higher refractive index mismatch between the scattering centers and surrounding materials enhances scattering efficiency and increases radiation extraction from ~20% to significantly higher values.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies scattering centers with locally optimized properties (high refractive index, appropriate size distribution) at specific locations within the OLED structure. This local quality enhancement maximizes scattering effectiveness at critical interfaces where total internal reflection would otherwise prevent radiation extraction.

Inventive Principle:

Principle #3Local quality

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 method produces a scattering layer with a smooth surface and adjustable scattering cross-section, improving the extraction of electromagnetic radiation from OLEDs by minimizing total internal reflection and preventing degradation, while maintaining structural integrity.

Implementation Method 1

liquefying of glass so that a part of the liquefied glass flows between the scattering centers toward the surface of the carrier

Methodology Applied

Scientific EffectLiquefaction of glass: Melting

Implementation Method 2

a scattering layer for scattering electromagnetic radiation... a larger proportion of the electromagnetic radiation generated, for example light, can be extracted

Methodology Applied

Scientific EffectScattering: Scattering

Data Source

PatentUS9945989B2Process for producing a scattering layer for electromagnetic radiation and scattering layer for scattering electromagnetic radiation

Publication Date: 2018.04.17 OSRAM OLED

AI summary

Various embodiments may relate to a process for producing a scattering layer for electromagnetic radiation. The process may include applying scattering centers onto a carrier, applying glass onto the scattering centers, and liquefying of the glass so that a part of the liquefied glass flows between the scattering centers toward the surface of the carrier, in such a way that a part of the liquefied glass still remains above the scattering centers.