Flexible Display Touch Lead Impedance Reduction via Protrusion
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Solution Overview
Problem
Flexible display devices with integrated touch functions face challenges due to the increased number of driving lines, which complicates the design of thinner foldable screens and requires more complex driving circuits, necessitating a solution to enhance the structural integrity and efficiency of the touch sensing units while maintaining flexibility.
Innovation Solution
The display device incorporates a substrate with a driving circuit layer, a light-emitting device layer, a thin film encapsulation layer, and a touch sensing unit, featuring a specific arrangement of inorganic and organic encapsulation layers, a touch insulation layer, and a second touch metal layer, along with a first dam and protrusions to optimize the touch lead structure, reducing impedance and allowing for a narrower bezel design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch function is integrated on a thin film encapsulation layer, then the display device achieves multi-functionality, but the number of driving lines is greatly increased
Solution Approach 1:
The patent divides the encapsulation structure into multiple functional layers (first inorganic encapsulation layer, organic encapsulation layer, second inorganic encapsulation layer) and separates the touch sensing unit from the display structure. This segmentation allows independent optimization of each layer, reducing the complexity of driving lines while maintaining multi-functionality.
Solution Approach 2:
The patent introduces a vertical stacking dimension by arranging encapsulation layers and touch sensing units in multiple layers above the substrate. This vertical arrangement reduces the horizontal space required for driving lines, thereby reducing overall device complexity while preserving touch functionality.
2Adaptability or versatility
If the number of driving lines is increased, then the touch sensing unit becomes more functional, but the foldable screen thickness increases
Solution Approach 1:
The patent implements a nested structure where the touch sensing unit is integrated within the encapsulation layers. The first inorganic encapsulation layer, organic encapsulation layer, and second inorganic encapsulation layer are arranged concentrically, with the touch sensing unit nested within this multi-layer structure. This nesting approach minimizes the overall thickness while maintaining full touch sensing functionality.
Solution Approach 2:
The patent employs thin film encapsulation layers (first inorganic encapsulation layer, organic encapsulation layer, second inorganic encapsulation layer) that provide both protection and flexibility. These thin films enable the integration of touch sensing functionality without significantly increasing the overall screen thickness, maintaining the flexibility required for foldable displays.
3Reliability
If the driving circuits are made more complex, then the touch sensing unit achieves better performance, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent segments the encapsulation and sensing functions into distinct layers (first inorganic encapsulation layer, organic encapsulation layer, second inorganic encapsulation layer, touch insulation layer, second touch metal layer). This segmentation allows each layer to be manufactured using optimized, simplified processes while achieving high overall performance.
Solution Approach 2:
The patent uses composite material structures combining different inorganic and organic layers. This composite approach leverages the advantages of each material type, enabling high-performance touch sensing with manufacturing processes that are simpler than using单一 complex materials.
4Area of stationary object
If the bezel width is reduced, then the display area increases, but the touch lead structure becomes more constrained
Solution Approach 1:
The patent transitions the touch lead structure from a primarily horizontal arrangement to a vertical arrangement by stacking sensing layers above the substrate. This vertical arrangement in another dimension allows for narrower bezels while providing sufficient space for touch lead connections without increasing horizontal constraints.
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 configuration enhances the flexibility and reliability of the touch sensing unit, reduces impedance, and facilitates a narrower bezel design by optimizing the touch lead structure, thereby improving the overall performance and usability of flexible display devices.
Implementation Method 1
an organic light-emitting diode including a first electrode, a light-emitting layer and a second electrode arranged on the driving circuit layer
Data Source
AI summary
The present disclosure provides a display device, including: an organic encapsulation layer, an area enclosed by a boundary of the organic encapsulation layer being a first area; and a first dam surrounding the display area, a second area being arranged between the first area and the first dam. A first touch lead is arranged in the second area, and a first protrusion is arranged between the first touch lead and the substrate. For the display device provided by the present disclosure, an actual width of the first touch lead is larger than a width of its projection onto the substrate. In a case of occupying a same bottom area, a resistance of the first touch lead in the present disclosure is greatly reduced, which greatly improves driving ability of the IC.