OLED Display Protective Film Stack for Trench Short-Circuit Isolation
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Solution Overview
Problem
In organic EL displays, a short circuit can occur between display wires and the second electrode due to the exposure of the protective film during the formation of a trench in the flattening films, leading to potential electrical failures.
Innovation Solution
The display device incorporates a protective film stack comprising a silicon oxide film, a silicon nitride film, and another silicon oxide film, which are sequentially layered to cover the display wires, preventing short circuits where the wires overlap with trenches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trench is provided in the first flattening film to prevent moisture ingress, then moisture protection is improved, but the protective film is partly removed during wet etching, causing short circuit risk
Solution Approach 1:
The patent applies preliminary action by forming the protective film on the display wire before forming the trench. This ensures that the protective film is already in place to prevent short circuits during subsequent wet etching processes, while still allowing the trench to be formed for moisture protection.
Solution Approach 2:
The patent segments the protective film formation and trench formation into separate sequential steps. The protective film is formed first, then the trench is formed through wet etching. This segmentation allows each process to be optimized independently while maintaining the protective function throughout.
2Ease of manufacture
If wet etching is used to form the metal wire layer, then manufacturing ease is improved, but the protective film is partly removed, establishing short circuit between display wire and second electrode
Solution Approach 1:
The protective film is formed preliminarily before the wet etching process. This preliminary formation ensures that when wet etching is performed to create the metal wire layer, the protective film remains intact and prevents any potential short circuits, thereby maintaining both manufacturing ease and protective film integrity.
3Reliability
If the display wire extends to the frame region adjacent to terminal section, then electrical connection is improved, but the wire overlaps with the trench, increasing short circuit risk
Solution Approach 1:
The protective film is formed on the display wire before the trench is formed. This preliminary protection ensures that even when the display wire overlaps with the trench in the frame region, the protective film prevents short circuits while maintaining electrical connection reliability.
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 protective film stack effectively prevents short circuits between display wires and the second electrode, ensuring reliable electrical connections and reducing the risk of electrical failures.
Implementation Method 1
the protective film includes a first protective film, a second protective film, and a third protective film sequentially stacked on the plurality of display wires... effectively prevents short circuits between display wires and the second electrode
Implementation Method 2
enhancing the reliability and durability of the organic EL display by maintaining electrical insulation and regulating stress
Data Source
AI summary
A TFT layer is provided that includes a stack of, in sequence, display wires, a protective film, a first flattening film, a metal wire layer and a second flattening film; further, a frame region has a first trench and a second trench respectively provided in the first flattening film and the second flattening film and overlapping the display wires; further, a second electrode is provided to cover the first trench and the second trench; further the protective film includes a first protective film and a third protective film formed of a silicon oxide film, and a second protective film formed of a silicon nitride film.