OLED Light Extraction via Sprayed Decoupling Layer

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Solution Overview

Problem

Existing organic light-emitting diodes (OLEDs) face significant efficiency losses due to waveguiding of light within organic layers and transparent substrates, resulting in substantial power loss of light generated, which current methods struggle to effectively mitigate.

Innovation Solution

A method for producing an organic radiation-emitting component that includes a radiation decoupling layer with a surface structure applied by spraying, which increases the decoupling of electromagnetic radiation from the organic radiation-emitting layer sequence, utilizing a transparent layer with a surface structure that enhances light scattering and reduces total reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If a transparent layer with a surface structure is applied by spraying to increase light decoupling, then light extraction efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvelight lossVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

A transparent radiation decoupling layer is introduced as an intermediary component between the organic radiation-emitting layer sequence and the external environment. This layer contains a surface structure that acts as a mediator to scatter waveguided light and increase the extraction efficiency, thereby reducing light loss without requiring fundamental changes to the OLED structure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index of the radiation decoupling layer is specifically optimized to be lower than that of the organic radiation-emitting layer sequence. This parameter change creates a stronger refractive index contrast at the interface, enhancing light scattering and decoupling effects. The surface structure parameters (roughness, feature size) are also optimized to match the wavelength of emitted light for maximum scattering efficiency

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the refractive index of the radiation decoupling layer is made lower than the organic radiation-emitting layer, then light scattering is enhanced, but manufacturing precision requirements increase

Engineering Contradiction:
Improvelight lossVSAvoidmanufacturing precision
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The radiation decoupling layer is applied as a separate, replaceable component that can be optimized and replaced without modifying the core OLED structure. This approach allows for easy optimization of refractive index and surface structure parameters while maintaining manufacturing simplicity, as the decoupling layer can be applied using conventional coating techniques

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The surface structure of the radiation decoupling layer is designed with features that exceed the minimum required for light scattering. This excessive action ensures robust light extraction performance across varying manufacturing tolerances, making the system less sensitive to precise manufacturing variations while maintaining enhanced light scattering

Inventive Principle:
Principle #16Partial or excessive action

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 approach significantly reduces light loss by improving the coupling-out of waveguided light, making a larger portion of the light usable and increasing the overall efficiency of the organic radiation-emitting component.

Implementation Method 1

the improved decoupling can be brought about by light scattering processes on the surface structure of the radiation decoupling layer

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 2

utilizing a transparent layer with a surface structure that enhances light scattering and reduces total reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2342771B9Method for producing an organic radiation-emitting component
Publication Date: 2016.08.31 OSRAM OLED
  • EP2342771B9 patent drawingFigure 1A~1B
  • EP2342771B9 patent drawingFigure 2A~2D
  • EP2342771B9 patent drawingFigure 3~5

AI summary

A method for producing an organic radiation-emitting component is provided, comprising the following steps: A) providing an organic radiation-emitting layer sequence (10) having at least one organic functional layer (3), which is suited to emit electromagnetic radiation during operation, and a transparent layer (11), B) applying a transparent radiation decoupling layer (20) having a surface structure (21) onto a surface (12) of the transparent layer (11) facing away from the at least one functional layer (3) by way of spraying. Furthermore, an organic radiation-emitting component is provided.