Display Panel Insulation Groove Layout for Pad Crack Prevention
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Solution Overview
Problem
Flexible display devices face stress-induced damage during bending and manufacturing, particularly due to delamination between the touch insulation layer and interlayer insulation film, leading to short-circuits and cracks around pads on the display panel.
Innovation Solution
A display apparatus with a groove pattern defined in the touch insulation layer prevents delamination between the touch insulation layer and interlayer insulation film, distributing stress and reducing the likelihood of cracks by not overlapping certain output pads, thereby enhancing the durability and reliability of the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch insulation layer is made continuous to ensure structural integrity, then the display panel maintains good mechanical strength, but delamination occurs between the touch insulation layer and interlayer insulation film under stress causing short-circuits
Solution Approach 1:
The touch insulation layer is segmented by introducing groove patterns that divide the continuous insulation layer into multiple sections. These grooves prevent delamination by creating separation lines that stop crack propagation and electrical short-circuits while maintaining overall structural integrity through the remaining insulation material.
Solution Approach 2:
The groove patterns are strategically positioned in specific locations where stress concentration is most likely to occur. By locally modifying the insulation layer structure at critical points rather than uniformly throughout, the design prevents delamination at stress-prone areas while maintaining good mechanical strength in other regions.
2Reliability
If the groove pattern is extended to cover the entire non-display area, then delamination prevention is maximized, but stress concentration occurs around outer pads causing cracks in the display panel
Solution Approach 1:
The groove pattern is selectively positioned to avoid overlapping with outer output pads while still providing delamination prevention in critical areas. This localized approach ensures that stress concentration around outer pads does not lead to cracks, while maintaining insulation reliability where needed.
Solution Approach 2:
Instead of extending grooves everywhere to maximize delamination prevention, the design inverts the approach by deliberately leaving gaps around outer pads. This inversion prevents the grooves from becoming stress concentration points that would cause cracks, while still providing adequate protection in other regions.
3Area of stationary object
If outer output pads are positioned at the edge of the display panel to maximize display area, then the display area is maximized, but stress concentration occurs around these pads during manufacturing and bending causing cracks
Solution Approach 1:
The groove pattern is strategically designed to avoid overlapping with outer output pads located at the edges of the display panel. This allows the pads to be positioned at the maximum edge location for optimal display area while the groove pattern provides stress distribution in other critical regions, preventing crack formation.
Solution Approach 2:
By segmenting the insulation layer with grooves that are strategically positioned away from outer pads, the design creates stress distribution pathways that prevent stress concentration at pad locations. This segmentation approach allows edge-positioned pads to maintain both display area maximization and stress resistance.
Data Source
AI summary
A display apparatus includes a substrate including a display area and a non-display area, a display element layer, a pad group, a touch electrode layer, and a touch insulation layer. The display element layer includes display elements disposed in the display area. The pad group is disposed on the substrate and includes output pads disposed in the non-display area. The output pads include central output pads and outer output pads disposed outside the central output pads in a first direction. The touch electrode layer is disposed on the display element layer. The touch insulation layer is disposed on the display element layer and contacts the touch electrode layer. A groove pattern is defined in the touch insulation layer overlapping the non-display area, and does not overlap at least a predetermined number of the outer output pads in a second direction.