OLED Dam Overflow Prevention via Differential Film Spread Rates
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Solution Overview
Problem
The conventional dam design in OLED display structures risks organic material overflow, leading to encapsulation failure and reduced bendability due to incomplete coverage by the inorganic layer, which fails to effectively isolate moisture and oxygen.
Innovation Solution
A display structure with different spread rates for the organic film layer on first and second inorganic film layers, slowing the spread rate near the dam area to prevent overflow and reduce the thickness of the encapsulation structure, thereby enhancing encapsulation reliability and bending resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dam structure is formed at the bezel to prevent organic material overflow, then encapsulation reliability is improved, but the total thickness of the film encapsulation increases, affecting bendability
Solution Approach 1:
The patent applies local quality by creating different surface energy characteristics at different locations. The first inorganic film layer has higher surface energy than the second inorganic film layer, causing the organic material to spread differently across the encapsulation area. This localized difference in surface energy prevents overflow at the dam while maintaining thin overall structure.
Solution Approach 2:
The patent changes the surface energy parameter of the inorganic film layers by using different materials or different deposition conditions for the first and second inorganic film layers. This parameter change controls the spread rate of organic material, allowing it to slow down near the dam area without increasing the overall thickness of the encapsulation structure.
2Length of stationary object
If the organic film layer spreads quickly on the inorganic film layer to reduce thickness, then bendability is improved, but the risk of organic material overflowing at the dam area increases
Solution Approach 1:
The patent creates a gradient in surface energy across the inorganic film layers. The first inorganic film layer (with higher surface energy) is positioned where quick spreading is needed to reduce thickness, while the second inorganic film layer (with lower surface energy) is positioned near the dam to slow spreading and prevent overflow. This spatial variation in surface energy resolves the contradiction between thickness reduction and overflow prevention.
Solution Approach 2:
The inorganic film layers act as intermediaries that mediate between the substrate and the organic material. By controlling the surface energy of these intermediary layers, the patent regulates the spread rate of organic material, enabling it to spread quickly in some areas (reducing thickness) while slowing down in other areas (preventing overflow).
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 the risk of organic material overflow, improves encapsulation reliability, and decreases the total thickness of the film encapsulation structure, enhancing the OLED display's bendability and moisture/oxygen isolation capabilities.
Implementation Method 1
the spread rates of an organic film layer on the first and second inorganic film layers are different, so as to slow the spread rate of the organic film layer near a dam area
Data Source
AI summary
A display structure is provided. The display structure includes a substrate, a dam, a first film layer, a second film layer, and a third film layer. The third film layer has a first spread rate for the first film layer, the third film layer has a second spread rate for the second film layer, and the first spread rate is less than the second spread rate. The spread rates of the third film layer on the first and second film layers are different, so as to slow the spread rate of the third film layer near an area of the dam, thereby reducing the risk that the third film layer overflows the dam, so that the encapsulation reliability of the display structure can be improved.