Electroluminescence Display Cathode Structure for Leakage Control
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Solution Overview
Problem
In high-resolution electroluminescence displays, the increased pixel density leads to lateral leakage currents between neighboring pixels, causing image quality deterioration and making it challenging to maintain a constant cathode voltage due to the high sheet resistance of transparent conductive materials used in top emission type structures.
Innovation Solution
The proposed electroluminescence display incorporates a low resistance line connected to the cathode electrode through a cathode contact hole, with a planarization layer and under-cut trench structure to minimize lateral leakage and maintain constant cathode voltage, featuring a pixel trench and bank configuration to optimize the emission area and reduce sheet resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If transparent conductive material is used for the cathode electrode in top emission type structure, then the emission area can be maximized, but the sheet resistance increases making it difficult to maintain constant cathode voltage
Solution Approach 1:
The cathode electrode structure is segmented into multiple components: transparent conductive layer, auxiliary cathode line, and main cathode line. This segmentation allows different regions to serve different functions - the transparent conductive layer maximizes emission area while the auxiliary and main cathode lines provide low-resistance voltage distribution paths, resolving the contradiction between large emission area and voltage stability.
Solution Approach 2:
The cathode electrode system performs multiple functions simultaneously: the transparent conductive material serves as both the emission surface and a conductive path, while the auxiliary cathode line provides additional voltage distribution. This multi-functionality allows the system to maintain both large emission area and stable cathode voltage.
2Measurement precision
If pixel density is increased for ultra-high resolution, then the resolution improves, but lateral leakage current between neighboring pixels increases causing image quality deterioration
Solution Approach 1:
The harmful lateral leakage current path is extracted and isolated by introducing the auxiliary cathode line that provides a dedicated low-resistance path for electron injection. This separates the desired current flow (through the emission layer) from the harmful lateral leakage, allowing high pixel density without image quality deterioration.
Solution Approach 2:
The auxiliary cathode line acts as an intermediary element between the transparent conductive layer and the main cathode line. It provides a controlled pathway that mediates the electron injection process, preventing uncontrolled lateral leakage while maintaining the benefits of high pixel density for ultra-high resolution.
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 effectively suppresses lateral leakage currents, ensuring stable image quality and constant cathode voltage across large-area, high-resolution displays by optimizing the emission area and reducing sheet resistance.
Implementation Method 1
an electroluminescence display comprises: a pixel disposed on a substrate... an emission layer on the bank, the anode electrode and the planarization layer
Data Source
AI summary
The present disclosure relates to an electroluminescence display. An electroluminescence display according to the present disclosure comprises: a pixel disposed on a substrate; a low resistance line disposed as one side of the pixel; a passivation layer on the low resistance line covering whole of the substrate; a planarization layer on the passivation layer covering whole of the substrate; a cathode contact hole exposing some of the low resistance line; an anode electrode disposed on the planarization layer; an under-cut trench formed at the planarization layer disposed between the anode electrode and the cathode contact hole; a bank covering circumference area of the anode electrode; an emission layer on the bank, the anode electrode and the planarization layer and a cathode electrode on the emission layer, wherein the cathode electrode connects the low resistance line through the cathode contact hole.