Curvy Organic Light Emitting Layer for Enhanced Light Extraction

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Solution Overview

Problem

Organic light emitting devices face inefficiencies in light extraction due to light being trapped within the device, leading to reduced outward light emitting efficiency and increased power consumption.

Innovation Solution

Incorporating a curvy organic light emitting layer with varying thickness and a corresponding overcoat layer structure, featuring convex or concave regions with specific slope and FWHM characteristics, to enhance light extraction by altering light paths and reducing reflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional flat organic light emitting layer is used, then the device structure is simple, but light extraction efficiency is low due to light being trapped inside the device

Engineering Contradiction:
Improvestructural simplicityVSAvoidlight extraction efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The organic light emitting layer is designed with a curvy shape including convex or concave regions instead of a flat structure. This curvature modifies light propagation paths and reduces total internal reflection at the interface between the organic light emitting layer and the overcoat layer, thereby improving light extraction efficiency while maintaining manufacturing feasibility through standard deposition processes

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The organic light emitting layer exhibits varying thickness locally, with thinner regions at the peaks of convex or concave curves and thicker regions in between. This local variation in thickness creates optimal conditions for light extraction at specific locations while maintaining overall structural integrity and manufacturing simplicity

Inventive Principle:
Principle #3Local quality

2Loss of energy

If the organic light emitting layer is made thinner to improve light extraction, then light extraction efficiency improves, but the layer may become too thin to maintain device reliability

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidlayer integrity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The organic light emitting layer is designed with spatially varying thickness, being thinner at the peaks of convex or concave curves where light extraction is most beneficial, and thicker in the valleys or between curves where structural support is needed. This local differentiation allows simultaneous optimization of light extraction efficiency and device reliability

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The curvy shape with convex or concave regions creates a profile where the thickness naturally varies, with the thinnest points located at the extrema of the curves. This geometric approach provides controlled thinning for light extraction while the overall curved structure maintains mechanical stability

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Improves outward light emitting efficiency and reduces power consumption by optimizing light emission through the use of a curvy organic light emitting layer and overcoat layer design, allowing trapped light to be extracted effectively.

Implementation Method 1

Light emitted from an organic light emitting layer of the organic light emitting device passes through several components of the organic light emitting device to exit from the organic light emitting device. However, some light emitted from the organic light emitting layer does not exit the organic light emitting device, but is locked in the organic light emitting device.

Methodology Applied
Scientific EffectLight refraction and reflection: Refraction

Implementation Method 2

The organic light emitting layer has a curvy shape including a plurality of convex regions or a plurality of concave regions... to enhance light extraction by altering light paths and reducing reflection

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4099418A1Organic light emitting device
Publication Date: 2022.12.07 LG DISPLAY CO LTD
  • EP4099418A1 patent drawingFigure 1~2A
  • EP4099418A1 patent drawingFigure 2B~3A
  • EP4099418A1 patent drawingFigure 3B~3C

AI summary

Provided is an organic light emitting device including an overcoat layer on a substrate, a first electrode disposed on the overcoat layer, an organic light emitting layer disposed on the first electrode and including a convex or concave curve; and a second electrode disposed on the organic light emitting layer.