Touch Electrode Width Compensation in Display Panel Edge Regions
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Solution Overview
Problem
Conventional display panels suffer from low touch sensitivity at positions close to the boundary of the display region due to the coffee-ring effect during inkjet printing of the organic packaging layer, leading to significant reduction in the width of the touch-control electrode metal lines.
Innovation Solution
The display panel is divided into regions with different thicknesses of the organic packaging layer, with the touch-control electrode metal lines in affected regions undergoing width compensation to maintain the designated width, reducing the absolute difference between the average widths in these regions to 0 to 0.32 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If inkjet printing is used to form the organic packaging layer, then the packaging layer can be formed with good coverage, but the coffee-ring effect causes significant width reduction of metal lines near the boundary region
Solution Approach 1:
The patent applies preliminary action by pre-compensating the metal line width in the boundary region before the coffee-ring effect occurs. The manufacturing process is adjusted in advance to create wider metal lines (by 0.1-0.5 μm) in the boundary region, so that after the organic packaging layer is printed and the coffee-ring effect reduces the width, the final width matches the design specification. This proactive compensation resolves the contradiction by preventing the harmful effect from causing precision loss.
Solution Approach 2:
The patent changes the parameter of metal line width differently in different regions. The boundary region uses a compensated width parameter (wider by 0.1-0.5 μm) while the center region uses the standard design parameter. This parameter differentiation accounts for the regional variation in coffee-ring effect intensity, maintaining manufacturing precision across the entire display region despite the harmful effect.
2Ease of manufacture
If the organic packaging layer is printed with uniform thickness, then the manufacturing process is simple, but the coffee-ring effect causes non-uniform thickness and metal line width variation
Solution Approach 1:
The patent applies local quality by implementing different metal line width specifications for different regions of the display panel. The boundary region (within 100-500 μm of the edge) receives compensated wider lines, while the center region maintains standard width. This localized differentiation addresses the regional variation in coffee-ring effect without complicating the overall manufacturing process, as it only requires modifying the patterning parameters for specific zones.
3Reliability
If metal line width is increased in the boundary region to compensate for coffee-ring effect, then touch sensitivity is improved, but the absolute difference in width between regions increases
Solution Approach 1:
The patent applies partial compensation by increasing the metal line width in the boundary region by a controlled amount (0.1-0.5 μm), not a full compensation that would make boundary lines much wider. This partial excessive action is sufficient to counteract the coffee-ring effect and maintain touch sensitivity, while minimizing the absolute width difference between regions. The compensated width is carefully chosen to be just enough to achieve reliability without excessive non-uniformity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves touch-control sensitivity at the boundary of the display region by ensuring the metal lines are closer to the designated width, enhancing the robustness and performance of the display panel.
Implementation Method 1
the coffee-ring effect during inkjet printing of the organic packaging layer, leading to significant reduction in the width of the touch-control electrode metal lines
Data Source
AI summary
A display panel, a method for manufacturing the same, and a display device. The display panel includes a substrate; a packaging layer at a side of the substrate, including an organic packaging layer comprising a first packaging portion and a second packaging portion different in thickness, a display region of the display panel including a first region and a second region in which the first packaging portion and the second packaging portion are disposed, respectively; a touch-control electrode at a side of the packaging layer away from the substrate, being a mesh electrode including first metal lines, an absolute difference between an average width of the first metal lines in the first region and an average width of the multiple first metal lines in the second region ranges from 0 to 32 μm, and the first metal lines in the second region being subject to width compensation.