Transparent Electrode Arrays for Uniform OLED Lighting

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Solution Overview

Problem

Optoelectronic devices face challenges in creating large uninterrupted lighted areas due to the presence of unlit regions, which disrupt the uniform appearance and are costly to manufacture, especially when using traditional manufacturing methods that limit pixel size and require complex processes or efficiency-reducing diffusing films.

Innovation Solution

The solution involves a roll-to-roll manufacturing process for optoelectronic device packages on flexible substrates, where transparent electrodes are deposited in continuous stripes, and an edge seal zone is created using a thin, broad adhesive layer to minimize water and oxygen ingress, allowing for larger lighted areas and simplified manufacturing by reducing the need for complex registration and alignment during deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the size of individual light emitting regions (pixels) is limited to maintain uniform appearance, then the device efficiency is improved due to lower resistive losses, but the area of lighted regions is reduced

Engineering Contradiction:
Improveresistive lossesVSAvoidarea of lighted regions
Core Design Contradiction:
Loss of energyVSArea of stationary object

Solution Approach 1:

The device is divided into multiple individual light emitting regions (pixels) that can be independently controlled. Each pixel is separated by unlit regions that serve as electrical isolation barriers, allowing the device to be segmented into functional units that can be addressed individually while maintaining overall device efficiency through localized current paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from controlling pixel size in two dimensions to using the third dimension (layer thickness) of transparent electrodes to manage electrical conductivity. By optimizing the thickness and material properties of transparent electrodes, the device achieves low resistive losses without being constrained by pixel dimensions, thereby enabling larger lighted areas.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If unlit regions are made very small to maintain uniform appearance, then the area of lighted regions is increased, but the manufacturing complexity is increased

Engineering Contradiction:
Improvearea of lighted regionsVSAvoidmanufacturing complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent combines multiple functional layers (transparent electrodes, active layers, encapsulation layers) into an integrated structure where unlit regions serve dual purposes: electrical isolation and structural support. This merging of functions reduces the number of separate manufacturing steps and simplifies the overall fabrication process while maintaining large lighted areas.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The unlit regions are designed to perform multiple functions simultaneously: electrical isolation between pixels, mechanical support for transparent electrodes, and optical shielding. This multi-functionality reduces the need for additional specialized structures, thereby simplifying manufacturing while enabling larger lighted regions.

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

3Ease of manufacture

If unlit regions are obscured with a diffusing film to maintain uniform appearance, then the manufacturing process is simplified, but the device efficiency is reduced and cost is increased

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddevice efficiency
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The patent extracts the optical diffusion function from a separate diffusing film layer and integrates it directly into the transparent electrode structure. By incorporating optical scattering centers within the electrode material itself, the device achieves uniform appearance without adding separate diffusing layers, thereby maintaining efficiency and reducing manufacturing complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The transparent electrodes are formulated as composite materials that combine electrical conductivity with optical scattering properties. This integration of multiple material functions into a single composite layer eliminates the need for separate diffusing films, maintaining device efficiency while simplifying the manufacturing process and reducing costs.

Inventive Principle:
Principle #40Composite materials

4Reliability

If transparent electrodes are made thicker to provide in-plane electrical conductivity, then the electrical conductivity is improved, but the optical transmission is reduced

Engineering Contradiction:
Improvein-plane electrical conductivityVSAvoidoptical transmission
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The transparent electrodes are constructed as composite materials that combine conductive fillers (such as metal nanoparticles or conductive polymers) within a transparent matrix. This composite structure provides sufficient in-plane electrical conductivity for device operation while maintaining high optical transmission, as the conductive components are distributed in a way that minimizes light scattering and absorption.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent optimizes the physical and chemical parameters of transparent electrode materials, including thickness, filler concentration, and material composition, to achieve the desired balance between electrical conductivity and optical transmission. By carefully controlling these parameters, the device achieves low resistive losses without significantly compromising light transmission efficiency.

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

This approach enables the creation of large arrays of lighted areas with reduced unlit regions, simplifying the manufacturing process, reducing costs, and maintaining high efficiency by minimizing resistive losses and maintaining optical transparency, thus enhancing the appearance and functionality of optoelectronic devices.

Implementation Method 1

an edge seal zone is created using a thin, broad adhesive layer to minimize water and oxygen ingress

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The light is transmitted through at least one of the electrodes of an OLED device. The design of a suitable transparent electrode requires that it provide in-plane electrical conductivity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The light is transmitted through at least one of the electrodes of an OLED device

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 4

In a light-emitting device, e.g., an organic light-emitting diode (OLED) device, a voltage applied between the two electrodes causes a current to flow through the active layer. The current causes the active layer to emit light.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 5

In a photovoltaic device, e.g., a solar cell, the active layer absorbs energy from light and converts it to electrical energy which generates a flow of current at some characteristic voltage between the two electrodes.

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP2761685B1Array of optoelectronic device packages and method of fabrication
Publication Date: 2019.10.02 BOE TECHNOLOGY GROUP CO LTD
  • EP2761685B1 patent drawingFigure 1~2
  • EP2761685B1 patent drawingFigure 3~4
  • EP2761685B1 patent drawingFigure 5~6

AI summary

An optoelectonice device package, an array of optoelectronic device packages and a method of fabricating an optoelectronic device package. The array includes a plurality of optoelectronic device packages, each enclosing an optoelectronic device, and positioned in at least one row. Each package including two geometrically parallel transparent edge portions and two geometrically parallel non-transparent edge portions, oriented substantially orthogonal to the transparent edge portions. The transparent edge portions are configured to overlap at least one adjacent package, and may be hermetically sealed. The optoelectronic device portion fabricated using R2R manufacturing techniques.