Grooved Non-Display Area for OLED Encapsulation Stress Relief
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Solution Overview
Problem
Existing OLED display panels face encapsulation failure when bent due to concentrated stress at retaining walls, leading to cracks and compromised thin-film encapsulation performance, as organic acrylic materials used for retaining walls are not resistant to bending.
Innovation Solution
A display panel design featuring a substrate with a groove in the non-display area surrounding the display area, where a thin-film encapsulation layer with alternating inorganic and organic layers is applied, including a groove shape that reduces stress and prevents water and oxygen intrusion, using materials like silicon nitride and epoxy resin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retaining wall made of organic acrylic material is provided to prevent organic material overflow, then the lateral encapsulation effect is improved, but the bending resistance deteriorates due to stress concentration and crack generation
Solution Approach 1:
The patent removes the problematic retaining wall structure entirely and replaces it with a groove structure formed directly on the substrate. This extraction of the harmful element (retaining wall) eliminates the source of stress concentration while maintaining the encapsulation function through the groove's physical barrier effect.
Solution Approach 2:
The invention changes the structural parameter from a protruding retaining wall to a recessed groove. This parameter change fundamentally alters the stress distribution during bending, transforming the stress concentration problem into a stress distribution solution that maintains both encapsulation and bending resistance.
2Reliability
If a retaining wall is provided to prevent organic material from flowing out, then the encapsulation performance is improved, but crack propagation occurs which further deteriorates the thin-film encapsulation performance
Solution Approach 1:
By removing the retaining wall and replacing it with a groove, the patent eliminates the structural element that causes crack initiation and propagation. The groove provides a stress-relief geometry that prevents crack formation, thereby maintaining structural integrity while preserving encapsulation performance.
Solution Approach 2:
The groove structure acts as a pre-designed stress relief feature that cushions against bending stresses before cracks can form. This beforehand cushioning prevents the stress concentration that would otherwise lead to crack propagation and encapsulation failure.
3Ease of manufacture
If organic acrylic material is used for the retaining wall to prevent material overflow, then the manufacturing process is simplified, but the bending resistance is reduced due to material properties
Solution Approach 1:
The patent extracts the retaining wall concept and replaces it with a groove structure that can be formed using standard substrate processing techniques. This eliminates the need for separate retaining wall materials and simplifies manufacturing while improving bending resistance through the groove's geometric stress relief.
Solution Approach 2:
The invention changes the structural parameter from a added retaining wall layer to a substrate groove. This parameter change allows the use of the substrate's own material properties for stress resistance while maintaining the anti-overflow function, thereby improving bending resistance without complicating manufacturing.
Data Source
AI summary
The present application proposes a display panel including a substrate including a display area and a non-display area surrounding the display area; a light-emitting layer located in the display area of the substrate; a groove obtained by exposing and developing the substrate, and disposed in the non-display area of the substrate and surrounding the display area; a thin-film encapsulation layer covering the light-emitting layer, and including an inorganic layer and an organic layer which are disposed alternately, wherein the organic layer is located in a region surrounded by the groove. The display panel has better bending resistance.