Touch Electrode Contact Pad Layout for Bendable Display Bonding
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Solution Overview
Problem
Current display panels, especially those with touch structures, face yield reduction due to the need for bonding with external circuits, which often leads to damage of inorganic and organic film layers, forming moisture-oxygen paths and causing film layers to fall off.
Innovation Solution
The display panel design includes a substrate with a bonding area and a bending area, featuring a gate driving circuit and a touch structure where the contact pad and touch electrode are in the same layer and made of the same material, with additional dummy contact pads and alignment marks to alleviate bonding stress, ensuring a segment difference of at least 0.5 μm, and strategically removing portions of the planarization and insulating layers to prevent film layer breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bonding is performed between the display panel and external circuit in the bonding area, then electrical connection is achieved, but the inorganic and organic film layers are damaged forming moisture-oxygen paths causing film layers to fall off
Solution Approach 1:
The bonding area is segmented from the display area by introducing a bending area with removed planarization and insulating layers. This segmentation isolates the bonding operation to a specific region, preventing damage propagation to the display area while maintaining electrical connection functionality.
Solution Approach 2:
The planarization layer and insulating layer are extracted (removed) from the bonding area to create a bending area. This extraction eliminates the vulnerable film layers from the bonding region, preventing their damage during bonding operations while preserving them in the display area.
2Device complexity
If the contact pad and touch electrode are in the same layer and made of the same material, then manufacturing complexity is reduced, but bonding stress concentration may occur
Solution Approach 1:
The contact pad is designed with local quality enhancement by extending beyond the touch electrode boundary and creating a larger bonding area. This local expansion distributes bonding stress over a wider area, preventing stress concentration while maintaining the same-layer same-material structure for manufacturing simplicity.
Solution Approach 2:
The contact pad structure extends in the planar dimension beyond the touch electrode, creating a dimensional transition from a confined pad-to-electrode relationship to an extended bonding interface. This dimensional expansion provides stress distribution pathways without adding vertical layer complexity.
3Manufacturing precision
If dummy contact pads and alignment marks are added to alleviate bonding stress, then film layer integrity is improved, but device complexity increases
Solution Approach 1:
Dummy contact pads and alignment marks are prepared in advance during the same manufacturing process as the functional contact pads. This preliminary action ensures precise alignment and stress distribution before bonding occurs, improving manufacturing precision without requiring additional complex steps.
Solution Approach 2:
The dummy contact pads serve multiple functions: they act as alignment references, stress distribution elements, and potential electrical test points. This multi-functionality reduces the need for separate alignment marks and stress relief structures, minimizing overall device complexity while achieving precision bonding.
Data Source
AI summary
The present disclosure provides a display panel and a display apparatus. The display panel includes: a substrate; and a touch structure located on a side, away from the substrate, of an organic light-emitting device and including a touch electrode and an insulating layer, a control chip connecting terminal is arranged in the bonding area at a position close to a bending area, the control chip connecting terminal is electrically connected with a gate driving circuit, a contact pad is arranged on a side, away from the bending area, of the control chip connecting terminal, the contact pad is configured to be capable of being bonded with a flexible printed circuit board, and at least part of the contact pad and at least part of the touch electrode are arranged in the same layer and made of the same material.