Flexible Display Panel Bending Area Stress Management
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Solution Overview
Problem
Existing flexible display panels face challenges in achieving a balance between flexibility and structural integrity, particularly in the bending area where signal leads and pattern layers are prone to breakage due to stress and thickness discrepancies.
Innovation Solution
The flexible display panel incorporates a flexible substrate with pixel driving circuits and a second organic material layer, along with a groove in the film layer, to manage stress and thickness variations. The ratio of the second organic material layer's thickness to the groove's distance from the substrate is optimized between 1:1 to 7:1, and the groove's design includes side surfaces with angles greater than or equal to 90 degrees or rounded angles with specific radii, to enhance bending resistance and reduce stress on signal leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the flexible display panel is made thinner and more flexible, then the flexibility and portability are improved, but the structural integrity and resistance to breakage in the bending area deteriorate
Solution Approach 1:
The patent introduces a groove structure specifically in the bending area of the flexible substrate, creating a local structural modification that allows controlled flexibility while maintaining overall structural integrity. The groove is positioned at the bending area to enable flexing without compromising the strength of other components like signal leads and pattern layers
Solution Approach 2:
The groove acts as an intermediary structure between the flexible substrate and the signal leads. It provides a stress-distributing interface that prevents direct stress concentration on the signal leads during bending, thereby maintaining both flexibility and structural integrity
2Reliability
If the thickness of the organic material layer is increased to improve bending resistance, then the reliability is improved, but the overall thickness and flexibility deteriorate
Solution Approach 1:
The patent optimizes the thickness parameter of the organic material layer in the bending area. By controlling the thickness to be within a specific range (1 μm to 10 μm), the patent achieves sufficient bending resistance while maintaining overall thinness and flexibility. This parameter optimization balances protection and flexibility requirements
3Reliability
If the groove is deeper to reduce stress on signal leads, then the reliability is improved, but the manufacturing precision requirements worsen
Solution Approach 1:
The patent specifies a controlled depth range for the groove (1 μm to 10 μm) to achieve effective stress distribution while maintaining manufacturability. This parameter specification balances the need for stress relief with practical manufacturing capabilities, avoiding excessive depth that would require ultra-precise fabrication
Data Source
AI summary
A flexible display panel has a display area, a bonding area, and a bending area located between the display area and the bonding area. A flexible substrate includes a first surface and a second surface. Signal leads electrically connected to pixel driving circuits pass through the bending area from the display area and extend to the bonding area. In the pixel driving circuits, at least one pattern layer made of an inorganic material and located between the signal leads and the flexible substrate passes through the bending area from the display area and extends to the bonding area. A second organic material layer is disposed on a side of the signal leads away from the first surface and located at the bending area. A groove is disposed in a film layer away from the signal leads, and is located between the display area and the bonding area.