Rollable Display Back Cover Buffer Zone Against Panel Cracking
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Solution Overview
Problem
Rollable display devices face issues with cracks due to pressure from cover plates and sealant overflow when rolled, particularly when using polyimide substrates, which can lead to driving failure and reliability concerns.
Innovation Solution
The implementation of a buffer zone outside the sealing layer, where the cover plate is positioned, to absorb stress and prevent cracks, combined with extending key elements like the substrate, buffer layer, and adhesive layers to eliminate level differences and overflow issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the display panel is pressed by a cover plate during rolling, then the display panel is secured and protected, but cracks occur in the display panel due to excessive pressure
Solution Approach 1:
A buffer layer is introduced between the cover plate and the display panel to provide beforehand cushioning. This buffer layer absorbs excessive pressure during rolling operations, preventing cracks in the display panel while still providing necessary support and security.
Solution Approach 2:
The buffer layer serves as an intermediary element between the cover plate and the display panel. It mediates the interaction by distributing pressure evenly and preventing direct concentrated forces from reaching the display panel, thus avoiding cracks while maintaining structural integrity.
2Adaptability or versatility
If glass under the polyimide substrate is removed, then flexibility is improved for rolling, but sealant overflows and causes driving failure
Solution Approach 1:
The buffer layer provides beforehand cushioning that prevents sealant overflow by absorbing excess sealant before it can reach areas that would cause driving failure. This allows the glass to be removed for flexibility while maintaining reliability through the protective buffer layer.
Solution Approach 2:
The buffer layer acts as an intermediary that controls sealant distribution. It prevents sealant from overflowing into areas that would cause driving failure, thus enabling the removal of glass for flexibility while maintaining reliable operation.
3Adaptability or versatility
If the display panel is made flexible for rolling, then rollable functionality is achieved, but cracks occur due to lack of structural support
Solution Approach 1:
The display structure uses composite materials including the polyimide substrate combined with the buffer layer. This composite structure provides both the flexibility needed for rolling and the structural support to prevent cracks, achieving rollable functionality without sacrificing strength.
Solution Approach 2:
The buffer layer provides beforehand cushioning that prevents cracks during rolling operations. This allows the display panel to be made flexible for rollable functionality while maintaining structural support through the protective buffer layer.
Data Source
AI summary
A display device includes a display panel; a back cover supporting the display panel on a rear surface of the display panel; a roller disposed on a rear surface of the back cover, wherein the display panel and the back cover are wound around or unwound from the roller; a flexible film electrically connected to a pad area of the display panel; and a sealing layer disposed to cover an end of the flexible film. At least some of elements of the display panel including a substrate may be extended beyond the sealing layer. Accordingly, it is possible to prevent cracks in the display panel due to the pressing by the cover plate and the overflow of the sealant, thereby solving the issues of driving failure and reliability of the display panel.