OLED Light-Emission Device with Elastic Conductor for Uniform Luminance

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Solution Overview

Problem

Large-area OLED elements face challenges in achieving uniform luminance due to the high impedance resistance of transparent electrodes, leading to undesired brightness differences and non-homogeneous current distribution, which complicates the production of evenly lit OLEDs for general lighting applications.

Innovation Solution

A light-emitting device design featuring a carrier with multiple lateral edge regions for power supply to the OLED element, utilizing an elongated electrical conductor element with elastic properties to ensure reliable contact and homogeneous current input, and a rectangular encapsulation element with extensive contact areas along its sides to facilitate uniform current introduction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent electrode with low surface resistance is used to ensure uniform current distribution, then luminance uniformity is improved, but the complexity of the device structure and manufacturing process increases due to the need for multiple feeding points and distributed contacting areas

Engineering Contradiction:
Improveluminance uniformityVSAvoiddevice structure complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The transparent electrode is divided into multiple electrically independent contact regions distributed along the lateral edges of the OLED element. Each contact region can be independently contacted, allowing uniform current distribution across the large-area electrode without requiring a single complex feeding structure

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of contacting the transparent electrode from a single point or line, the invention transitions to distributed contacting along the lateral edges (one-dimensional distribution). This dimensional approach allows multiple feeding points to be arranged along the perimeter, reducing voltage gradients and improving luminance uniformity across the electrode surface

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

2Area of stationary object

If the OLED element is made large-area to achieve diffuse lighting, then the lighting application potential is improved, but the voltage drop within the transparent electrode increases leading to non-uniform brightness

Engineering Contradiction:
ImproveOLED element areaVSAvoidbrightness uniformity
Core Design Contradiction:
Area of stationary objectVSIllumination intensity

Solution Approach 1:

The large-area transparent electrode is segmented into multiple contact regions along its lateral edges. This segmentation allows the electrode to function as a large-area component while maintaining uniform current distribution by providing multiple access points for current injection, thereby reducing the effective current path length and voltage drop across the electrode surface

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the transparent electrode are assigned different functions: the central large area is optimized for light emission, while the lateral edge regions are optimized for electrical contacting. This local differentiation allows the electrode to simultaneously achieve large emitting area and uniform current distribution by concentrating contact points at the periphery

Inventive Principle:
Principle #3Local quality

3Stability of the object's composition

If multiple contacting regions are provided on the transparent electrode to improve current distribution, then luminance homogeneity is improved, but the manufacturing precision requirements increase due to the need for precise electrical contacting at multiple locations

Engineering Contradiction:
Improvecurrent distribution homogeneityVSAvoidcontacting precision
Core Design Contradiction:
Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The invention transitions from point-contact or line-contact configurations to distributed areal contacting along the lateral edges. This dimensional approach distributes the contacting requirements along the perimeter, reducing the precision burden at any single location while maintaining overall current distribution homogeneity across the electrode

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

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 design enhances the mechanical and electrical properties of the light-emitting device, reducing the risk of contact failure under mechanical stress or temperature fluctuations, and achieves a more uniform light output by minimizing voltage drop and ensuring homogeneous current distribution across the OLED element.

Implementation Method 1

an electrical conductor element (31, 32) for an electrical connection between the carrier (20) and the OLED element (10), wherein the electrical conductor element (31, 32) is designed in such a way that it has elastic properties in a direction normal to the OLED element (10)

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

An OLED element has two flat electrodes between which an 'active' or organic layer made of organic materials is embedded. When a suitable voltage is applied or a suitable current is impressed, light is emitted by the active organic layer.

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP2834862B1Light-emission device with an OLED element
Publication Date: 2020.03.11 TRIDONIC GMBH & CO KG
  • EP2834862B1 patent drawingFigure 1~3
  • EP2834862B1 patent drawingFigure 2
  • EP2834862B1 patent drawingFigure 4

AI summary

The invention relates to a light-emission device with a two-dimensional OLED element and an encapsulation element (15) for protecting the OLED element. The light-emission device furthermore has a support (20), on which the OLED element is arranged in such a way that the encapsulation element (15) points toward the support (20), and an electrical conductor element (31) for an electrical connection between the support (20) and the OLED element, wherein the electrical conductor element (31) is elastic in a normal direction to the OLED element. By way of example, the conductor element (31) can be helical. As a result of the elastic property thereof, the conductor element (31) can absorb mechanical tension while ensuring reliable electrical contacting. Hence, this can reduce or even avoid the risk of the electrical connection between the support (20) and the OLED element being disadvantageously influenced or impaired by forces which can occur when handling the light-emission device or which can be generated by temperature variations.