OLED Display Panel Sidewall Layout for Stable Cathode Overlap
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Solution Overview
Problem
The evaporation process for forming a cathode in an OLED display device can lead to poor overlapping between the cathode and the isolation structure, posing a risk of electrical connectivity issues.
Innovation Solution
A display panel design with a pixel defining layer and sub-pixel units, where the isolation structure's sidewall includes a conductive portion and a shielding structure, with specific distance and orientation configurations to enhance conductive overlap stability between the cathode and the isolation structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cathode is formed through an evaporation process without using fine metal mask, then the manufacturing cost is reduced, but the overlapping between the cathode and the isolation structure becomes poor
Solution Approach 1:
The isolation structure is designed with asymmetric distance relationships: the distance from the first sidewall to the sub-pixel edge is smaller than the distance from the second sidewall to the sub-pixel edge. This asymmetric configuration compensates for the evaporation source's directional deposition characteristics, ensuring that the cathode material overlaps properly with the conductive portion despite the simplified evaporation process without fine metal mask.
Solution Approach 2:
The isolation structure's conductive portion is selectively positioned and dimensioned to create different local properties: the first conductive region has different overlapping characteristics compared to the second conductive region. This local differentiation ensures that each area provides appropriate electrical connection and shielding based on its specific functional requirements, thereby improving overall overlapping stability.
2Reliability
If the shielding structure extends beyond the conductive portion, then the electrical connection stability is improved, but the device complexity increases
Solution Approach 1:
The shielding structure and the isolation structure are merged into a single integrated component. The conductive portion is formed as an integral part of the isolation structure's sidewall, eliminating the need for separate shielding components. This merging approach maintains reliable electrical connection and shielding functionality while avoiding the increased complexity that would result from adding distinct separate structures.
3Reliability
If the second distance is greater than the first distance in the sidewall configuration, then the conductive overlap stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The isolation structure is pre-configured with predetermined asymmetric distances before the cathode evaporation process. The first and second distances are carefully designed in advance to account for the evaporation source's deposition characteristics. This preliminary configuration ensures that even with variations in the evaporation process, the cathode will overlap stably with the conductive portion, thereby improving reliability while managing manufacturing precision requirements through proactive design.
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 ensures stable electrical connection between the cathode and the isolation structure, improving the conductive overlap stability and reducing the risk of pixel crosstalk.
Implementation Method 1
A light-emitting layer and a cathode of the sub-pixel may be sequentially evaporated on the corresponding one of the plurality of pixel openings through an evaporation source
Data Source
AI summary
A display panel and a display device are provided. Each sub-pixel unit includes a sub-pixel and an isolation structure. A sidewall of the isolation structure includes a conductive portion and a shielding structure. The sidewall includes a first sidewall and a second sidewall. In the first sidewall, a distance between an edge of the shielding structure and an adjacent edge of the conductive portion is a first distance. In the second sidewall, a distance between an edge of the shielding structure and an adjacent edge of the conductive portion is a second distance. Within each sub-pixel unit, the second distance is greater than the first distance. Alternatively, in a planar direction substantially parallel to a pixel defining layer, an edge of the sub-pixel extending in a length direction of the evaporation source and an adjacent edge of the sidewall are obliquely disposed to each other.