Top Emission OLED Overcoating Layer Convex Concave Light Extraction

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Solution Overview

Problem

Organic light emitting diode (OLED) display devices face low light extraction efficiency due to light being trapped within the device, leading to increased power consumption and reduced external light emission.

Innovation Solution

A top emission type OLED display device is designed with an overcoating layer featuring convex or concave portions, a reflection plate, and electrodes that match the morphology of the overcoating layer, enhancing light extraction efficiency by altering the light path and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

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

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

Solution Approach 1:

The patent introduces convex and concave portions on the surface of the OLED device, creating curved micro-lens structures that alter light propagation paths. These curved surfaces refract and redirect trapped light outward, significantly improving light extraction efficiency without complicating the overall device manufacturing process

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent modifies surface geometry parameters by creating specific convex and concave portions with controlled dimensions and distributions. By changing the surface topology parameters, the optical properties of the device are improved, enabling better light extraction while maintaining structural simplicity

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If light extraction efficiency is improved using micro-lens structures, then external light emission increases, but device complexity increases

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoiddevice structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the micro-lens array structure with the existing OLED device layers, integrating the light extraction function into the device structure itself rather than adding separate components. This merging approach improves light extraction efficiency while minimizing the increase in device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The convex and concave portions serve multiple functions: they act as micro-lenses for light extraction, provide surface texturing for enhanced optical coupling, and can be formed using standard semiconductor processing techniques. This multi-functionality reduces the need for additional specialized components

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design significantly improves external light emission efficiency and reduces power consumption by optimizing the light path through the use of a micro lens array structure, allowing more light to be extracted externally while minimizing inefficient emission areas.

Implementation Method 1

an overcoating layer disposed on a substrate and including a plurality of convex portions or a plurality of concave portions

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

a reflection plate on the overcoating layer

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3343659B1Top emission type organic light emitting diode display device
Publication Date: 2021.06.16 LG DISPLAY CO LTD
  • EP3343659B1 patent drawingFigure 1~2A
  • EP3343659B1 patent drawingFigure 2B~3A
  • EP3343659B1 patent drawingFigure 3B~3C

AI summary

The present disclosure includes a organic light emitting diode display device, preferably a top emission type organic light emitting diode display device. The top emission type organic light emitting diode display device of the disclosed present disclosure includes an overcoating layer disposed on a substrate and including a plurality of convex portions or a plurality of concave portions in which a full width at half maximum is greater than a radius, a first electrode disposed on the overcoating layer, an organic light emitting layer disposed on the first electrode, and a second electrode disposed on the organic light emitting layer.