OLED Resistance Gradient for Uniform Large-Area Lighting
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Solution Overview
Problem
Light-emitting organic components, such as OLEDs, face challenges in achieving homogeneous light distribution across larger surface areas due to variations in electrical feed resistance, leading to uneven light intensity, which is undesirable for lighting applications.
Innovation Solution
The implementation of a light-emitting organic component with an electrical resistance gradient in the organic layer array, formed through layer thickness or doping gradients, compensates for position-dependent electrical feed resistances, ensuring a constant current flow and homogeneous lighting appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the surface area of the light-emitting organic component is increased, then the lighting coverage is improved, but the homogeneity of light distribution deteriorates due to voltage drop across the transparent electrode
Solution Approach 1:
The patent applies local quality by creating a non-uniform electrical resistance distribution within the organic layer array. Specifically, the resistance is varied spatially to compensate for the position-dependent voltage drops in the transparent electrode, ensuring that each region of the large-area component receives appropriate current compensation to maintain uniform light emission across the entire surface area.
2Reliability
If IMI stacks (ITO-metal-ITO) are used instead of ITO, then the electrical conductivity is improved by a factor of about 5, but the problem of non-uniform light distribution is only partially solved
Solution Approach 1:
The patent applies parameter changes by systematically varying the electrical resistance parameter within the organic layer array. By adjusting the resistance distribution spatially, the invention compensates for the voltage drops that occur even with improved IMI stack conductivity, thereby achieving uniform light distribution across large areas while maintaining high electrical conductivity throughout the device.
3Reliability
If an additional metal grid is arranged on or under the transparent electrode, then the surface resistivity is reduced dramatically, but the production complexity increases and the active area is reduced
Solution Approach 1:
The patent applies the taking out principle by removing the need for additional metal grids or complex electrode structures. Instead of adding external resistance-reduction elements, the invention extracts and addresses the root cause by modifying the resistance distribution within the existing organic layer array, thereby maintaining full active area and simple production processes while achieving the desired electrical performance.
4Illumination intensity
If several small light-emitting organic components are arranged to form larger lighting areas, then the light distribution homogeneity is maintained, but additional costs for structuring and masking steps are incurred
Solution Approach 1:
The patent applies merging by combining multiple resistance compensation approaches into a single integrated solution within the organic layer array. By varying the resistance distribution continuously across the layer, the invention achieves uniform light emission in large-area components without requiring multiple separate component assemblies, thereby eliminating the need for additional structuring and masking steps while maintaining production efficiency.
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 results in a spatially homogeneous light density and improved performance efficiency, maintaining current efficiency while reducing light intensity variations across the component's surface area, making it suitable for various applications including lighting and displays.
Implementation Method 1
an electrical resistance gradient in a direction substantially parallel to the electrode surface area being formed within a region of the organic layer array
Implementation Method 2
compensates for position-dependent electrical feed resistances, ensuring a constant current flow
Data Source
AI summary
The invention relates to a light-emitting organic component, in particular a light-emitting organic diode, having an electrode spreading over an electrode surface area and a counter electrode spreading over a counter electrode surface area as well as an organic layer array formed between the electrode and the counter electrode and in electrical contact therewith, an electrical resistance gradient in a direction substantially parallel to the electrode surface area being formed within a region of the organic layer array at least partially overlapping with the electrode surface area. Furthermore, the invention relates to a method for the production of a light-emitting organic component.