OLED Bank Protrusion Layout for Leakage-Resistant Sub-Pixels
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Solution Overview
Problem
Existing display devices face challenges in reducing light emission caused by leakage currents and ensuring stable disconnection of organic layers, which affects efficiency and lifespan, particularly in multi-stack organic light emitting diode (OLED) structures.
Innovation Solution
A display device with a multi-stack structure featuring a substrate with emission and non-emission areas, where a bank with protrusions is used to expose electrodes and disconnect the organic layer from the cathode at inclined surfaces, reducing lateral leakage currents and enhancing color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a multi-stack structure is used to improve efficiency and lifespan, then light emission efficiency is improved, but leakage current between adjacent sub-pixels increases causing unintended light emission
Solution Approach 1:
The common organic layer is segmented into first and second organic layers by introducing protrusions that physically separate the layers. This segmentation prevents leakage current from the first sub-pixel from affecting adjacent sub-pixels while maintaining the multi-stack structure's efficiency benefits.
Solution Approach 2:
Protrusions are introduced as intermediary structures between adjacent sub-pixels. These protrusions act as mediators that block lateral leakage current paths while allowing the multi-stack configuration to function properly, thus resolving the contradiction between efficiency and leakage.
2Ease of manufacture
If a common organic layer is used to simplify manufacturing, then production yield is improved, but leakage current causes unintended light emission in adjacent sub-pixels
Solution Approach 1:
The common organic layer is divided into separate first and second organic layers through protrusions. This segmentation maintains manufacturing simplicity while preventing leakage current from causing unintended light emission in adjacent sub-pixels.
3Stability of the object's composition
If the organic layer is continuously connected to ensure stable structure, then structural stability is improved, but leakage current cannot be blocked between sub-pixels
Solution Approach 1:
The organic layer is segmented into first and second organic layers by protrusions. This segmentation blocks leakage current paths while maintaining structural stability through the bank and protrusion framework that provides mechanical support and defined geometry.
4Object-generated harmful factors
If bank structure is added to block leakage current, then leakage current is reduced, but device complexity increases
Solution Approach 1:
The protrusions are integrated with the bank structure, merging two functional elements into a unified structure. This combination blocks leakage current while minimizing the increase in device complexity by using a single fabrication process to create both the bank and protrusions.
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 configuration improves the efficiency and lifespan of OLEDs by reducing unintended light emission and stabilizing the disconnection of organic layers, leading to enhanced production yield and display quality.
Implementation Method 1
a bank which is disposed in the non-emission area between the plurality of sub-pixels and exposes the first electrode through an opening... a protrusion disposed in a second non-emission area of the non-emission area... the organic layer and the second electrode are disconnected from each other at a side surface of the protrusion between adjacent sub-pixels
Data Source
AI summary
A display device includes a substrate including an emission area and a non-emission area and in which a plurality of sub-pixels are defined, first electrodes disposed in the plurality of sub-pixels, respectively, a bank that is disposed in the non-emission area between the plurality of sub-pixels, and exposes the first electrode through an opening, a protrusion disposed in a second non-emission area of the non-emission area which is divided into a first non-emission area at a flat top surface of the bank and the second non-emission area at an inclined top surface of the bank, an organic layer disposed on the first electrodes, and a second electrode disposed on the organic layer.