Organic Light-Emitting Device Fuse Layer for Current Uniformity
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Solution Overview
Problem
Organic light emitting devices with large areas face issues with uniform current injection and light emission due to high resistance in electrodes, leading to non-uniform brightness and potential electrical shorts, which can cause defects in the entire device.
Innovation Solution
Incorporating a fuse layer on the second electrode with varying thicknesses or patterns, including gaps between metal layers, to automatically disconnect excessive current and prevent electrical shorts, ensuring uniform current distribution and maintaining device functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high driving current is used to achieve high brightness in large area devices, then brightness is improved, but current uniformity deteriorates due to electrode resistance
Solution Approach 1:
The electrode is divided into multiple segments with different thicknesses, where thicker regions provide lower resistance for higher current density and thinner regions provide higher resistance for lower current density, enabling uniform current distribution across the large area device
Solution Approach 2:
Different regions of the electrode are given different thicknesses to match the local current requirements, with thicker electrode regions positioned where higher current is needed and thinner regions where lower current is needed, achieving local optimization of current uniformity
2Reliability
If metal oxide anode material with large work function is used, then hole injection is improved, but electrical conductivity deteriorates causing voltage drop
Solution Approach 1:
The electrode is constructed as a composite structure combining metal oxide material (providing high work function for efficient hole injection) with varying thickness profile (providing lower overall resistance by having thicker regions in high-current areas), thus achieving both good hole injection and low voltage drop
3Reliability
If metal cathode material with small work function is used, then electron injection is improved, but transparency deteriorates when formed as thin film
Solution Approach 1:
The cathode electrode uses a metal material with varying thickness, combining the benefits of high electron injection efficiency (from the metal's small work function) with improved transparency (from the thinner regions allowing light passage), achieving both good electrical performance and optical 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 fuse layer effectively prevents electrical shorts and ensures uniform light emission across large areas by automatically disconnecting excessive current, maintaining device stability and brightness, and allowing for easier repair of defects.
Implementation Method 1
the fuse layer effectively prevents electrical shorts and ensures uniform light emission across large areas by automatically disconnecting excessive current
Data Source
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AI summary
The present invention relates to an organic light emitting device and a method for preparing the same, and the organic light emitting device according to the present invention comprises: a substrate; a first electrode provided on the substrate; an organic material layer provided on the first electrode; a second electrode pattern provided on the organic material layer and comprising two or more metal layers spaced apart from each other; and a fuse layer provided in an entire region of an upper surface of the second electrode pattern and gaps between the metal layers spaced apart from each other.