Flexible Display Pixel Trench and Partition Wall Stress Management
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Solution Overview
Problem
Flexible display devices face challenges in maintaining image quality and durability due to stress from deformation, such as folding or bending, which can lead to peeling and cracking of light-emitting elements and transistors, and crosstalk between adjacent pixels.
Innovation Solution
The implementation of a trench structure between pixels, where the EL layer is in contact with the interlayer insulating film via the trench, and a partition wall covering the edge of the first electrode, helps distribute deformation stress and reduces crosstalk by increasing the resistance of the EL layer in the lateral direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible display device is designed to be bendable, then adaptability is improved, but stress concentration occurs at pixel boundaries causing peeling and cracking
Solution Approach 1:
The pixel structure is divided into multiple sub-pixels with partition walls between them. The partition walls create separate regions that can independently accommodate deformation, preventing stress concentration at pixel boundaries and reducing peeling and cracking during bending.
Solution Approach 2:
The EL layer is configured to extend beyond the pixel electrode area, creating different structural zones within the pixel. This local variation in layer configuration allows certain regions to better accommodate stress during deformation while maintaining display functionality in the active area.
2Ease of manufacture
If the EL layer is extended beyond the pixel electrode area, then manufacturing is simplified, but crosstalk between adjacent pixels increases
Solution Approach 1:
Partition walls are introduced to segment the EL layer into distinct regions corresponding to different sub-pixels. This segmentation allows the EL layer to extend beyond electrode areas for manufacturing simplicity while preventing lateral current flow and crosstalk between adjacent pixels through the insulating partition walls.
Solution Approach 2:
The partition walls act as intermediary insulating structures between adjacent EL layer regions. These partition walls provide electrical isolation that prevents crosstalk while allowing the EL layer to maintain a continuous, extended structure that simplifies the deposition process.
3Object-generated harmful factors
If partition walls are introduced between pixels, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
The partition walls are formed as part of the insulating film structure that already exists in the device architecture. By combining the partition wall formation with existing insulating layer deposition processes, the structural complexity increase is minimized while still achieving effective crosstalk prevention.
Data Source
AI summary
Provided is a display device including a first sub-pixel, a second sub-pixel adjacent to the first sub-pixel. The first sub-pixel and the second sub-pixel each include a semiconductor film, a gate electrode, a gate insulating film, an interlayer insulating film, and a leveling film and further possesses a light-emitting element located over the leveling film. The display device has a partition wall located between the first sub-pixel and the second sub-pixel and a trench passing through the leveling film.