Dam Structure Prevents Adhesive Overflow in Rollable Display
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Solution Overview
Problem
Rollable display devices face issues with conductive adhesive layer overflow and un-curing of micro seals, leading to substrate curling and flexible film tearing, which affect the reliability and functionality of the display panel.
Innovation Solution
A display device design that includes a dam at the end of the substrate to contain the conductive adhesive layer and a sealing layer to prevent un-curing of the micro seal, thereby suppressing the curling of the polyimide substrate and tearing of the flexible film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the conductive adhesive layer is applied without a dam structure, then the adhesive can properly bond the flexible film to the substrate, but the adhesive overflows at the end of the substrate causing reliability issues
Solution Approach 1:
The invention introduces a dam structure that segments the substrate surface into a bonding region and a non-bonding region. The dam is formed by removing the organic EL layer and encapsulation layer at the end portion of the substrate, creating a physical barrier that prevents adhesive overflow while maintaining bonding functionality in the designated area.
Solution Approach 2:
The dam structure acts as an intermediary element between the conductive adhesive layer and the substrate end. This intermediary structure controls the spread of the adhesive, allowing it to bond effectively within the bounded region while preventing harmful overflow beyond the dam structure.
2Reliability
If the micro seal is applied without a dam structure, then the seal can cover the end of the substrate, but the seal remains un-cured causing substrate curling and flexible film tearing
Solution Approach 1:
The dam structure segments the substrate into cured and un-cured regions. By creating a bounded area with the dam, the micro seal can be properly contained and cured within this region, preventing un-cured seal material from causing substrate curling while maintaining sealing coverage.
Solution Approach 2:
The dam structure serves as an intermediary that enables proper curing of the micro seal. The bounded region created by the dam allows UV light to effectively cure the seal material, preventing the un-cured state that would otherwise cause substrate deformation and flexible film damage.
3Reliability
If a dam structure is added to prevent adhesive overflow and ensure seal curing, then reliability improves, but the device structure becomes more complex
Solution Approach 1:
The dam structure is created by selectively removing existing layers (organic EL layer and encapsulation layer) rather than adding entirely new components. This approach increases reliability through proper adhesive containment and seal curing while minimizing the increase in structural complexity by utilizing the existing layer structure.
Data Source
AI summary
According to an exemplary embodiment of the present disclosure, a display device includes a display panel having a substrate, a back cover which supports the display panel on one surface of the display panel, a flexible film which is electrically connected to a pad unit of the display panel, a sealing layer which covers one ends of the pad unit and the flexible film and a dam which is disposed at an end of the display panel in which the flexible film is located and is in contact with a rear surface of the flexible film. Therefore, according to the present disclosure, the overflowing of the conductive adhesive layer at the end of the substrate is suppressed and the un-curing of the micro seal is suppressed to suppress the curling of the polyimide substrate and the tearing of the flexible film.