Auxiliary Wiring Line Edge Coverage for EL Layer Protection
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Solution Overview
Problem
The existing self-luminous light-emitting devices with auxiliary wiring lines suffer from damage to the electroluminescence layer due to permeation of etching solutions during patterning, leading to reduced luminous efficiency.
Innovation Solution
A light-emitting device design featuring a bank with a through hole, a lower layer electrode, an upper layer electrode, an electroluminescence layer, a high refractive index layer, and an auxiliary wiring line with a corresponding through hole, where the auxiliary wiring line's peripheral edge covers the refractive index layer, preventing etching solution permeation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an auxiliary wiring line is formed on an upper layer electrode to reduce resistance, then electrical conductivity is improved, but the EL layer is damaged by etching solution permeation
Solution Approach 1:
A protective layer is formed on the EL layer before forming the auxiliary wiring line. This preliminary protective layer prevents etching solution from permeating into the EL layer during the patterning process, while still allowing the auxiliary wiring line to be formed for reducing electrical resistance.
Solution Approach 2:
The protective layer acts as an intermediary barrier between the etching solution and the EL layer. It allows the etching process to proceed for forming the auxiliary wiring line while protecting the underlying EL layer from damage, thus mediating between the need for low resistance and EL layer integrity.
2Use of energy by moving object
If a high refractive index layer is provided to improve light extraction, then optical efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The protective layer serves multiple functions: it protects the EL layer from etching solution damage and also functions as a refractive index management layer to improve light extraction efficiency. By combining these functions in a single layer, the device complexity is minimized while achieving both protection and optical enhancement.
Solution Approach 2:
The refractive index of the protective layer is specifically controlled to be between 1.3 and 1.7, which is lower than the EL layer's refractive index. This parameter optimization enables improved light extraction efficiency through refractive index contrast without requiring additional complex optical layers.
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 design effectively suppresses damage to the electroluminescence layer and enhances luminous efficiency by reducing resistance and improving light extraction.
Implementation Method 1
a first refractive index layer provided on the upper layer electrode in the first through hole and having a refractive index greater than 1.7
Implementation Method 2
having a refractive index greater than 1.7
Data Source
AI summary
A light-emitting device includes a high-refractive-index material layer provided on a third electrode in an opening of a bank, and an auxiliary wiring line. The auxiliary wiring line is formed on the third electrode and includes an opening provided corresponding to the opening, and a peripheral edge portion thereof surrounding the opening covers a peripheral edge portion of the high-refractive-index material layer in a plan view.