Display Device Passivation Layer Omission for Crack Prevention
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Solution Overview
Problem
Display devices with curved parts face challenges in preventing cracks during the bending process, particularly due to the stress concentrations at varying curvatures, which can lead to structural integrity issues and reduced reliability.
Innovation Solution
The implementation of a display device design where the passivation layer is strategically omitted from the minimum curved parts of the display panel, allowing for reduced thickness and stress distribution, while maintaining protection on the flat and peripheral areas, thereby preventing cracks during the formation of curved parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a passivation layer is formed on the entire display unit including curved parts, then protection of the sensing unit is improved, but cracks are generated during the bending process
Solution Approach 1:
The passivation layer is segmented into different regions: it is formed on the flat part and peripheral areas of the display unit, but intentionally omitted from the curved parts. This segmentation allows the structure to maintain protection where needed while avoiding stress concentration in bending regions, thereby preventing cracks during the bending process.
Solution Approach 2:
Different regions of the display unit are treated differently regarding passivation layer formation. The flat part receives full passivation protection, while the curved parts are left without passivation layer to accommodate bending stresses. This local differentiation optimizes both protection and structural integrity in respective regions.
2Stress or pressure
If the passivation layer is made thinner in curved parts, then stress distribution is improved, but protection capability is reduced
Solution Approach 1:
The passivation layer is completely removed (taken out) from the curved parts of the display unit, rather than merely thinning it. This extraction eliminates the source of stress concentration in bending regions while maintaining full protection capability in the flat and peripheral areas where the passivation layer remains intact.
3Strength
If the passivation layer is omitted from curved parts, then cracks are prevented during bending, but protection of the sensing unit is reduced
Solution Approach 1:
The passivation layer is segmented to cover only the flat part and peripheral areas, while being omitted from curved parts. This segmentation strategy prevents cracks in bending regions while maintaining adequate protection of the sensing unit in areas where the passivation layer is present.
Solution Approach 2:
The display unit structure is designed with local quality differentiation: highly protected regions (flat and peripheral areas with passivation layer) and flexible regions (curved parts without passivation layer). This allows the sensing unit to be protected where structurally safe while accommodating bending stresses where necessary.
Data Source
AI summary
A display device includes: a display unit including a flat part and a curved part which is formed to be bent from sides of the flat part; a sensing unit on the display unit to overlap with the flat part and the curved part; and a passivation layer on the sensing unit, wherein the passivation layer overlaps with the flat part and the passivation layer does not overlap the curved part.