Flexible Display Substrate Bending Region Structure
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Solution Overview
Problem
Flexible display devices face reliability issues when bent or curved due to moisture and contaminant ingress through cracks in the inorganic insulating layer, leading to degradation of light-emitting elements and reduced durability.
Innovation Solution
A flexible display device substrate with a stacked structure of a first resin layer, a first inorganic insulating layer, and a second resin layer, where the inorganic insulating layer and inorganic material layer are removed in the bending region to improve adhesion and prevent moisture ingress, and the second resin layer is thicker than the first resin layer to minimize gas desorption and peeling, enhancing bending resistance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inorganic insulating layer is used in the substrate structure, then moisture barrier performance is improved, but cracking occurs in the bending region leading to reduced reliability
Solution Approach 1:
The substrate structure transitions from uniform to non-uniform by removing the inorganic insulating layer specifically in the bending region while maintaining it in the display region. This local modification allows the bending region to have flexible, crack-resistant properties while the display region retains the moisture barrier benefits of the inorganic layer.
Solution Approach 2:
The substrate is divided into functionally distinct regions: a display region with complete protective layers for moisture barrier performance, and a bending region with removed inorganic layers for flexibility. This segmentation allows each region to be optimized for its specific function without compromising the other.
2Adaptability or versatility
If the substrate is made thinner to improve flexibility, then bendability is improved, but structural integrity and resistance to degradation worsen
Solution Approach 1:
Different thickness configurations are applied to different regions: the display region maintains a balanced multi-layer structure for structural integrity, while the bending region uses a thinner configuration without the inorganic insulating layer to maximize flexibility and prevent cracking during bending operations.
3Adaptability or versatility
If resin layers are used without inorganic insulating layer in bending region, then flexibility and adhesion are improved, but gas desorption and peeling may occur
Solution Approach 1:
The thickness of the resin layers is optimized to prevent gas desorption and peeling. Specifically, the first resin layer is set to 50-200 nm and the second resin layer to 200-500 nm, creating a configuration that provides sufficient mechanical stability and adhesion while maintaining the flexibility needed for the bending region.
Data Source
AI summary
The display device includes a substrate including a first resin layer, a second resin layer overlapping the first resin layer, and a first inorganic insulating layer between the first resin layer and the second resin layer, and having flexibility, a display region provided on the substrate, a terminal region arranged outside the display region on the substrate, and a bending region arranged between the display region and the terminal region. A thickness of the second resin layer is larger than a thickness of the first resin layer. The substrate includes a first region and a second region. The first resin layer, the first inorganic insulating layer, and the second resin layer are laminated in the first region. The first resin layer and the second resin layer are laminated in the second region and the first inorganic insulating layer is not laminated in the second region.