Graphene Microlens Structures for OLED Light Extraction

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Solution Overview

Problem

Organic light-emitting diodes (OLEDs) suffer from significant light loss due to absorption, reflection, and surface plasmon losses, limiting their light output efficiency to around 60-70% with existing external output methods altering the appearance of OLEDs and internal output methods not being market-ready.

Innovation Solution

Incorporating graphene-based light-refracting structures, such as lens-like graphene bubbles, within the optoelectronic component to enhance light input or output without increasing production complexity, where the graphene layer can form part of the electrodes or be arranged outside the electrically active region, and can be integrated economically into the production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If external output methods (scattering sheets, surface structures) are used to increase light output, then light output efficiency is improved, but the appearance of OLED is substantially influenced (milky/diffusely reflective surface)

Engineering Contradiction:

Improvelight output efficiencyVSAvoidappearance of OLED

Core Design Contradiction:

Loss of energyVSShape

Solution Approach 1:

The patent introduces an intermediate layer containing microlenses between the OLED and the external environment. This intermediary structure redirects light internally without requiring external scattering sheets or surface structures that would alter the OLED's appearance. The microlenses act as mediators that extract light from the substrate while maintaining a clean, uniform external surface.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from two-dimensional surface structures (scattering sheets, surface patterns) to three-dimensional microlens structures embedded within the device layers. This dimensional shift allows light extraction through volumetric optical elements that do not compromise the external appearance, as the lenses are integrated internally rather than applied as external coatings.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Loss of energy

If external output methods (scattering sheets, surface structures) are used to increase light output, then light output efficiency is improved, but output efficiency is limited to approximately 60 to 70% of the light guided in the substrate

Engineering Contradiction:

Improvelight output efficiencyVSAvoidlight extraction efficiency

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

The patent applies optical functionality locally at specific positions within the device structure rather than uniformly across the entire surface. Microlenses are strategically placed in regions where light extraction is most beneficial, creating localized zones of enhanced light output without requiring blanket application of scattering materials that limit overall efficiency to 60-70%.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent employs curved microlens structures instead of flat surface modifications. The spherical or lens-shaped geometry provides superior light redirection capabilities compared to planar scattering surfaces, enabling more effective extraction of guided modes from the substrate and achieving light output efficiency exceeding the 60-70% limitation of conventional methods.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Loss of energy

If internal output methods are used to output light guided in organics and transparent electrode, then light output efficiency is improved, but these methods are not yet available on the market in OLED products

Engineering Contradiction:

Improvelight output efficiencyVSAvoidmarket readiness

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent modifies optical parameters within the existing device architecture by introducing microlenses with specific refractive indices and geometries. This parameter-based approach allows internal light extraction enhancement without fundamentally changing the manufacturing process or material composition, making the technology compatible with current production capabilities and ready for market deployment.

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

Significantly improves light output or input efficiency in OLEDs by reducing total reflection and absorption losses, offering new possibilities for structured substrates and maintaining the appearance of OLEDs, while being economically viable.

Implementation Method 1

graphene-based light-refracting structures, such as lens-like graphene bubbles

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

reducing total reflection and absorption losses

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentUS9224985B2Optoelectronic component

Publication Date: 2015.12.29 DOLYA HOLDCO 5 LTD

AI summary

An optoelectronic component may include an electrically active region and a light-refracting structure which includes at least one graphene layer, in which at least one lens-like structure is formed. The electrically active region may include a first electrode, a second electrode, and an organic functional layer structure between the first electrode and the second electrode.