OLED Common Layer Thickness Variation for Leakage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
OLED devices face a light leakage issue due to leakage current through the common layer, which affects color characteristics and efficiency, especially at low gray levels.
Innovation Solution
A common layer with a thinner thickness on the bank compared to the anode, allowing for easier doping and improved hole and electron injection characteristics, reducing lateral current leakage and minimizing light emission from adjacent sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the common layer has a large thickness on the bank, then the manufacturing process is simpler, but leakage current increases causing light leakage from adjacent sub-pixels
Solution Approach 1:
The common layer is designed with non-uniform thickness: thicker on the anode (for better hole injection) and thinner on the bank (for reduced leakage current). This local variation in thickness allows each region to optimize its function - the anode region benefits from thicker layer for charge injection while the bank region minimizes harmful lateral current leakage to adjacent sub-pixels.
Solution Approach 2:
The common layer thickness is segmented into different regions: a first thickness on the bank and a second thickness on the anode. This segmentation allows independent optimization of each region's thickness to meet different functional requirements - preventing leakage at the bank while maintaining injection efficiency at the anode.
2Area of stationary object
If the common layer has a large thickness, then the layer provides better coverage, but dopant material cannot be easily doped and injection characteristics deteriorate
Solution Approach 1:
The common layer thickness is optimized locally: thinner on the bank for easy doping and better injection characteristics, while maintaining adequate coverage area. The reduced thickness on the bank enables effective dopant diffusion without compromising overall layer coverage on the anode region.
3Stability of the object's composition
If the common layer has a large thickness, then the structural stability is improved, but lifetime and efficiency of organic light emitting element decrease
Solution Approach 1:
The common layer thickness is optimized locally: thinner on the bank to reduce leakage current and improve device lifetime, while maintaining adequate thickness on the anode for structural stability and proper function. This local optimization resolves the contradiction between structural stability and device lifetime.
Data Source
AI summary
An organic light emitting display (OLED) device, and a method for manufacturing the OLED device are discussed. The OLED device according to one embodiment includes a substrate; an anode formed on the substrate; a bank formed on the substrate to partially overlap the anode; an organic light emitting element including a portion of a common layer on the anode and another portion of the common layer on the bank, the portion of the common layer on the bank being thinner than the another portion of the common layer on the anode; and a cathode fanned above the portion of the common layer on the anode and the another portion of the common layer on the bank.