Flexible Display Substrate Groove Design for Crack Reduction
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Solution Overview
Problem
Display devices with flexible substrates face challenges in bending without cracking, due to stress accumulation and poor adherence between the substrate and protection layers, leading to potential cracking and detachment during bending.
Innovation Solution
A display device design featuring a substrate with a groove in the bending area, an insulating layer with through-holes aligned with the groove, and a protection layer with protrusions that penetrate the insulating layer and groove, enhancing stress relief and adherence, thereby reducing cracking and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible substrate is used to enable bending, then the display device can be deformed and dead space is reduced, but the substrate is prone to cracking and detachment during bending due to stress accumulation
Solution Approach 1:
The substrate is divided into a bending area and non-bending areas by forming grooves that segment the structure. This segmentation allows the bending area to flex independently while the non-bending areas maintain structural integrity, preventing stress-induced cracking during bending operations.
Solution Approach 2:
A protection layer is formed in advance over the bending area to cushion and distribute stress before bending occurs. This protection layer acts as a pre-established buffer that absorbs bending stresses and prevents them from reaching critical levels that would cause substrate cracking or layer detachment.
2Ease of operation
If the substrate is made flexible to reduce dead space, then easier deformation is achieved, but adherence between substrate and protection layers deteriorates leading to detachment
Solution Approach 1:
Different regions of the substrate are given different properties: the bending area is made more flexible through groove formation while the non-bending areas maintain strong adherence. The protection layer is selectively positioned and configured to provide enhanced local bonding in the bending area through protrusions that interlock with the groove structure, ensuring adherence is maintained where flexibility is needed.
Solution Approach 2:
The protection layer is nested within the groove structure of the substrate, with protrusions of the protection layer fitting into the grooves. This nested configuration creates an interlocking mechanism that maintains strong adherence between layers while allowing the overall structure to bend flexibly without detachment.
3Ease of manufacture
If the substrate structure is simplified to enable bending, then manufacturing is easier, but stress relief capability is reduced leading to cracking
Solution Approach 1:
The substrate is segmented into bending and non-bending areas using grooves, creating a structure that is relatively simple to manufacture while effectively relieving stress. The groove pattern provides clear stress relief pathways without requiring complex multi-layer or multi-component structures, maintaining ease of manufacture while improving reliability.
Data Source
AI summary
A display device according to some example embodiments includes: a substrate including a first area, a second area, and a bending area between the first area and the second area; a display unit overlapping the first area; and a protection layer overlapping the bending area, wherein the substrate includes a groove at the bending area, and the protection layer is formed in the groove.