Flexible Display Cathode Curvature Stress Relief
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Solution Overview
Problem
Flexible displays face issues with cathode breakage due to stress during bending, affecting display quality due to the plate-shaped metal cathode's lack of flexibility.
Innovation Solution
A flexible display design featuring a pixel defining layer with arc-shaped protrusions and grooves, where the cathode conforms to these shapes, reducing stress concentration and allowing for stress release during bending, preventing cathode breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a plate-shaped metal cathode is used in the flexible display, then the display structure is simple and manufacturing is easy, but the cathode breaks when bent due to stress during the bending process
Solution Approach 1:
The cathode is designed with a curved surface that conforms to the arc-shaped protrusions and grooves on the pixel defining layer. This curvature allows the cathode to flex and deform elastically during bending without breaking, resolving the contradiction between ease of manufacture and reliability by maintaining structural integrity while enabling flexibility.
Solution Approach 2:
The cathode's shape parameters are changed from a flat plate to a curved surface with specific arc profiles. These parameter changes enable the cathode to accommodate stress during bending through elastic deformation, preventing breakage while maintaining manufacturing feasibility through conformal deposition processes.
2Reliability
If the cathode is made flexible to prevent breakage during bending, then reliability is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The cathode is implemented as a thin film structure that can be deposited conformally on the curved pixel defining layer. This thin film approach provides the necessary flexibility and elasticity to prevent breakage during bending, while the conformal deposition process keeps manufacturing complexity manageable by following the existing substrate geometry.
Solution Approach 2:
The curved surface design of the cathode, conforming to arc-shaped protrusions and grooves, inherently provides flexibility and stress relief during bending. This geometric design achieves reliability improvement without requiring additional complex flexible support structures, thus limiting the increase in device complexity.
3Reliability
If the cathode is designed with curve shapes to release stress during bending, then flexibility and reliability are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The pixel defining layer is first formed with predetermined arc-shaped protrusions and grooves that define the desired cathode curvature. This preliminary action establishes the stress-release geometry before cathode deposition, allowing the cathode to be deposited conformally with standard precision requirements rather than requiring post-deposition shaping operations.
Solution Approach 2:
The cathode's geometric parameters are predetermined by the pixel defining layer's arc-shaped features. By transferring the curvature definition to the supporting pixel defining layer, the manufacturing precision requirement for the cathode itself is reduced, as the cathode simply needs to conform to the pre-established geometry through standard deposition processes.
Data Source
AI summary
Disclosed are a flexible display and a manufacturing method thereof. The flexible display includes a first flexible substrate, a pixel defining layer and a cathode. The pixel defining layer includes a plurality of first separation walls and a plurality of second separation walls. The first separation wall has protrusions and a first groove with openings far away from the first flexible substrate and extending in the length direction of the first separation wall; and the second separation wall has protrusions and a second groove with an opening far away from the first flexible substrate and extending in the length direction of the second separation wall. A part of the cathode that faces against the first separation wall has a curve shape conforming to the first groove, and a part of the cathode that faces against the second separation wall has a curve shape conforming to the second groove.