Auxiliary Electrode Patterning for Large High-Definition OLED Displays
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Solution Overview
Problem
The existing electroluminescent display devices face challenges in achieving large size and high definition due to manufacturing variations and costs associated with the vacuum thermal evaporation process, particularly with the preparation of fine metal masks, which leads to issues like sagging and shadow effects.
Innovation Solution
The electroluminescent display device incorporates a substrate with a first electrode, a connection pattern made of the same material, a bank covering the edges, a light-emitting layer, a second electrode, and an auxiliary pattern that includes metal oxide, conductive nanoparticles, or a work function-modifying polymer, with the connection pattern having a protrusion within the auxiliary pattern to improve electrical contact and reduce manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If vacuum thermal evaporation process with fine metal mask is used to form light-emitting layers, then manufacturing precision of sub-pixels is improved, but manufacturing cost increases and device size is limited
Solution Approach 1:
The patent extracts the fine metal mask from the manufacturing process entirely, replacing it with a self-aligned patterning method using sol-gel processing and thermal decomposition. This eliminates the need for expensive mask preparation while maintaining sub-pixel formation precision, directly resolving the contradiction between manufacturing precision and ease of manufacture.
Solution Approach 2:
The patent replaces the mechanical vacuum thermal evaporation process with a chemical solution-based sol-gel process followed by thermal decomposition. This substitution eliminates the need for vacuum equipment and fine metal masks, enabling large-scale manufacturing while maintaining precise sub-pixel patterning through chemical self-organization.
2Manufacturing precision
If fine metal mask is used in vacuum thermal evaporation, then light-emitting layer deposition precision is improved, but mask sagging and shadow effects occur
Solution Approach 1:
The patent removes the fine metal mask from the deposition process entirely. Instead, it uses a spin-coated sol-gel solution that is thermally decomposed to form the light-emitting layer, eliminating mask-related defects such as sagging and shadow effects while maintaining deposition precision through controlled chemical processes.
Solution Approach 2:
The patent replaces the mechanical mask-based physical vapor deposition with a chemical solution process. The sol-gel solution is applied by spin-coating and then thermally decomposed to form the light-emitting layer, eliminating all mechanical mask-related issues while achieving precise patterning through chemical self-organization and controlled decomposition.
3Device complexity
If connection pattern and second electrode are directly connected, then device structure is simplified, but contact resistance increases and current concentration occurs
Solution Approach 1:
The patent introduces an auxiliary pattern as an intermediary layer between the connection pattern and the second electrode. This auxiliary pattern, formed from the same sol-gel solution, provides improved electrical contact and current distribution, reducing contact resistance and preventing current concentration while adding minimal structural complexity.
Solution Approach 2:
The patent uses a composite structure where the auxiliary pattern is formed from the same sol-gel material as the light-emitting layer but with different thermal decomposition conditions. This creates a material composition gradient that optimizes both electrical contact properties and structural integration, improving reliability without significantly increasing device complexity.
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 enhances the display's ability to achieve large size and high definition while reducing manufacturing costs and improving luminance and power efficiency by minimizing contact resistance and preventing current concentration phenomena.
Implementation Method 1
an auxiliary pattern between the connection pattern and the second electrode, the auxiliary pattern including one or more of: a metal oxide, conductive nanoparticles, and a work function-modifying polymer
Implementation Method 2
a light-emitting layer on the first electrode
Data Source
AI summary
An electroluminescent display device includes: a substrate, a first electrode on the substrate, a connection pattern on the substrate, the connection pattern including a same material as the first electrode, a bank covering edges of the first electrode and the connection pattern, a light-emitting layer on the first electrode, a second electrode on the light-emitting layer, the bank, and the connection pattern, and an auxiliary pattern between the connection pattern and the second electrode, the auxiliary pattern including one or more of: a metal oxide, conductive nanoparticles, and a work function-modifying polymer.