OLED Substrate with Segmented Electrode for Uniform Luminance
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Solution Overview
Problem
In organic electronic devices, particularly OLEDs with large emitting areas, high sheet resistance of electrodes leads to non-uniform electron injection and luminance, making it challenging to achieve uniform emission across the entire emitting region.
Innovation Solution
A substrate structure with a planarized surface featuring a recessed conductive pattern in an adhesive layer, which includes scattering particles and a conductive surface layer, allows for precise control of sheet resistance, ensuring uniform luminance and emission efficiency even in large-sized OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the transparent electrode thickness is reduced to ensure transparency, then light extraction efficiency is improved, but sheet resistance control becomes difficult
Solution Approach 1:
The electrode structure is segmented into multiple functional layers: a thin transparent conductive oxide layer (for transparency) combined with a metal layer (for low sheet resistance). This segmentation allows each layer to perform its specialized function without compromise.
Solution Approach 2:
The patent employs composite electrode structures combining transparent conductive oxides (ITO, IZO, ZnO) with metal layers (Al, Ag, Mo). This composite approach integrates the transparency advantage of oxides with the low resistance advantage of metals, resolving the contradiction between transparency and sheet resistance control.
2Area of stationary object
If the OLED emitting area is increased to achieve large display size, then device coverage is improved, but luminance uniformity deteriorates due to high sheet resistance
Solution Approach 1:
The electrode is segmented into multiple layers with different materials and functions. The metal layer provides extensive lateral charge distribution capability, while the TCO layer maintains transparency. This segmentation enables large emitting areas with uniform luminance by preventing voltage drops across the electrode surface.
Solution Approach 2:
The patent optimizes the thickness and material composition parameters of each electrode layer to achieve the desired balance between transparency and sheet resistance. By carefully controlling these parameters, large OLEDs can maintain uniform luminance across the entire emitting area.
3Device complexity
If a single-layer transparent electrode is used to simplify structure, then device complexity is reduced, but sheet resistance and transparency cannot be simultaneously optimized
Solution Approach 1:
The electrode is divided into functionally distinct layers: a TCO layer for transparency and a metal layer for low resistance. This segmentation allows simultaneous optimization of both transparency and electrical performance, overcoming the limitations of single-layer electrodes.
Solution Approach 2:
The multi-layer electrode structure performs multiple functions simultaneously: the TCO layer provides transparency and basic conductivity, while the metal layer provides enhanced conductivity and serves as a barrier. This multi-functionality justifies the increased structural complexity by delivering superior overall performance.
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 substrate structure effectively controls sheet resistance and enhances light extraction efficiency, resulting in uniform luminance and improved emission characteristics across the entire emitting area of large-sized OLEDs.
Implementation Method 1
a conductive pattern 13 recessed in the adhesive layer 12, wherein the adhesive layer includes a surface layer formed on a surface thereof opposite to the substrate
Implementation Method 2
the adhesive layer includes a surface layer formed on a surface thereof opposite to the substrate
Data Source
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AI summary
The present invention relates to a substrate for an organic electrode device, a manufacturing method thereof, and an organic electronic device. An exemplary substrate of the invention, if an organic light emitting element is formed on an upper part of the substrate, can obtain luminance with high emission and uniformity by efficiently controlling the surface resistance of an electrode even when the device is configured into larger sizes.