Organic EL Display Anode Voltage Uniformity via Charge Functional Layer
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Solution Overview
Problem
Conventional organic EL display panels face issues with uneven voltage distribution and increased manufacturing complexity due to the need for patterning multiple layers, leading to high costs and degradation in display quality.
Innovation Solution
The implementation of a configuration where a cathode electrode, auxiliary wiring, bank with aperture areas, an anode electrode, and a charge functional layer are used, with the anode electrode receiving power via the charge functional layer, which reduces contact resistance and unifies the current path across the display region, thereby equalizing voltage distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If patterning is performed on each of the layers included in the light-emitting functional layer, then light-emitting elements can be formed, but the manufacturing process becomes complicated and costs increase
Solution Approach 1:
The patent segments the light-emitting functional layer into multiple independent layers (hole injection layer, hole transport layer, organic light-emitting layer, electron transport layer, electron injection layer) that can be formed separately without requiring patterning of each layer. This allows the functional layer to be constructed through sequential deposition of distinct material layers, each serving a specific charge transport or emission function, thereby eliminating complex patterning processes while maintaining precise light-emitting element formation
Solution Approach 2:
The patent employs a common electrode structure that serves multiple functions: it acts as an electrical contact, a barrier layer, and a reflective layer. This multi-functional electrode design eliminates the need for separate patterned electrodes for each light-emitting element, simplifying the manufacturing process while maintaining precise control over light emission through the organic light-emitting layer alone
2Device complexity
If a common electrode is used to cover all light-emitting functional layers, then device structure is simplified, but uneven voltage distribution occurs in the effective region
Solution Approach 1:
The patent introduces auxiliary lines connected to the common electrode to create multiple equipotential regions across the effective area. These auxiliary lines are positioned at strategic locations to ensure uniform voltage distribution, compensating for the inherent voltage drop that would occur in a simple common electrode structure. This allows the maintained structural simplicity while achieving uniform voltage and improved display quality
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 voltage uniformity and reduces display quality degradation by minimizing contact resistance and simplifying the manufacturing process, leading to more consistent and cost-effective organic EL display panels.
Implementation Method 1
an organic light-emitting layer, and a cathode electrode, wherein the organic light-emitting layer is between the anode electrode and the cathode electrode
Data Source
AI summary
An organic electroluminescence (EL) display panel includes an anode electrode formed above a bank and formed opposite to a plurality of cathode electrodes, and a charge functional layer commonly formed for each of the organic light-emitting layers across a plurality of aperture areas formed in the bank. A distance from the center of the display region to the end of the anode electrode is shorter than a distance from the center of the display region to the end of the charge functional layer.