Passivation Layer Layout for Foldable Display Bending Stress
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Solution Overview
Problem
Flexible display devices face issues with stress concentration and defects in bending areas, as well as the inflow of external static electricity, which can lead to cracks and other damage.
Innovation Solution
Incorporating a passivation layer and an organic insulating layer with specific spacing to reduce stress and block external static electricity, along with a polarization layer and touch electrodes, to protect the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible display panel is bent to reduce dead space, then the display device can be folded and transformed, but stress concentration occurs in the bending area leading to cracks and defects
Solution Approach 1:
The patent applies a passivation layer and organic insulating layer as flexible protective films that can accommodate bending without cracking. These thin film layers are specifically designed to follow the contour of the bent display panel while providing continuous protection against stress concentration and environmental damage in the bending area.
Solution Approach 2:
The passivation layer and organic insulating layer are formed beforehand in the bending area to cushion and distribute mechanical stress before bending occurs. This pre-established protective structure prevents stress concentration and crack initiation during subsequent folding operations.
2Adaptability or versatility
If the display panel is made flexible for transformation, then it can be folded and unfolded, but external static electricity can infiltrate and cause defects
Solution Approach 1:
The organic insulating layer acts as a flexible barrier film that maintains electrical isolation between the display panel and external environment during folding. This continuous insulating film prevents static electricity infiltration while accommodating the flexible transformation of the display device.
Solution Approach 2:
The passivation layer and organic insulating layer serve as intermediary protective barriers between the vulnerable display panel and external static electricity. These intermediate layers block harmful electrical charges while allowing the flexible structure to maintain its transformability.
3Length of stationary object
If layers are placed close together to reduce device thickness, then the structure is more compact, but stress concentration increases in bending areas
Solution Approach 1:
The patent applies different layer configurations at different locations: in the bending area, the passivation layer and organic insulating layer are formed with specific thicknesses and spacing to reduce stress concentration, while in non-bending areas, the structure can be more compact. This local differentiation allows stress management in critical areas without compromising overall device thinness.
Data Source
AI summary
A display device includes a display panel including a first area, a second area, and a bending area between the first area and the second area, a passivation layer at the bending area, and at a part of the first area adjacent to the bending area, a polarization layer at the first area, and spaced apart from the passivation layer, and an organic insulating layer between the polarization layer and the display panel, having an end portion at the first area of the display panel, and including a first part that overlaps the polarization layer, a second part that overlaps the passivation layer at the first area, and a third part between the first part and the second part, and overlapping an entirety of a spacing area between the polarization layer and the passivation layer.