Organic Light-Emitting Display Bank Metal Pattern for Lateral Current Leakage
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Solution Overview
Problem
Conventional organic light-emitting display devices suffer from lateral current leakage due to the continuous formation of organic layers across sub-pixels, leading to color purity deterioration and unintended illumination, especially in low-gradation displays.
Innovation Solution
Incorporating a metal pattern on the bank to electrically separate the common organic layer by applying current or a constant voltage, thereby preventing lateral current leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If organic layers are continuously formed across sub-pixels without shadow mask, then manufacturing complexity is reduced and productivity is improved, but lateral current leakage occurs causing color purity deterioration
Solution Approach 1:
The patent introduces a bank structure with a metal pattern that divides the continuous organic layer into separate regions for different sub-pixels. The metal pattern creates physical and electrical separation between adjacent sub-pixels, preventing lateral current leakage while allowing continuous formation of organic layers. This segmentation approach maintains manufacturing efficiency while restoring color purity by isolating current paths to vertical directions only.
Solution Approach 2:
The bank with metal pattern serves as an intermediary structure between adjacent sub-pixels. It acts as a barrier that blocks lateral current flow through the common organic layer while allowing vertical current flow within each sub-pixel. The metal pattern in the bank structure functions as an electrical isolator that prevents harmful lateral current leakage without interfering with the normal operation of individual sub-pixels.
2Manufacturing precision
If shadow mask is used to form organic light-emitting layer, then color purity is maintained, but device complexity increases and productivity decreases due to mask droop and yield rate deterioration
Solution Approach 1:
The patent removes the shadow mask from the manufacturing process entirely. Instead of using a shadow mask to define sub-pixel boundaries during organic layer formation, the design extracts the boundary-defining function to the bank structure with metal pattern. This allows continuous deposition of organic layers without masks, eliminating mask-related complexity and productivity issues while maintaining precise sub-pixel separation through the bank structure.
Solution Approach 2:
The bank structure with metal pattern is formed beforehand, before the continuous deposition of organic layers. This preliminary action creates the separation boundaries in advance, allowing subsequent organic layers to be deposited continuously without requiring mask intervention. The pre-formed bank structure ensures that even though organic layers are deposited continuously, they will be electrically separated by the pre-positioned metal pattern in the bank.
3Ease of manufacture
If common organic layer is formed across sub-pixels, then ease of manufacture is improved, but harmful lateral current flow occurs between adjacent sub-pixels
Solution Approach 1:
The patent converts the potentially harmful continuous organic layer into a beneficial structure by introducing the metal pattern in the bank. The continuous organic layer, which would normally cause lateral current leakage, is transformed into a useful common layer for electrical isolation when combined with the metal pattern. The metal pattern modifies the electrical properties of the continuous organic layer, turning it from a source of harmful lateral current into a structure that facilitates vertical current flow while blocking lateral flow.
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
The solution effectively reduces lateral current leakage, maintaining color purity and preventing unintended illumination between sub-pixels, even when highly conductive organic layers are deposited, without altering the bank's structure or increasing mask usage.
Implementation Method 1
Incorporating a metal pattern on the bank to electrically separate the common organic layer by applying current or a constant voltage, thereby preventing lateral current leakage
Data Source
Figure 1
Figure 2
Figure 3~4A
AI summary
Disclosed are an organic light-emitting display device and a method of manufacturing the same, which prevent lateral current leakage by providing a bank (120, 220, 230, 320, 330) with a metal pattern (132, 232, 332) so as to realize electrical separation of a common layer (135a, 240, 340) formed thereon.