Buried Touch Line Layout for Narrow-Bezel Display Panels
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Solution Overview
Problem
The increase in the size of the outer area due to the lines connected to touch sensing electrodes in display devices is undesirable, affecting the bezel formation and image display efficiency.
Innovation Solution
The arrangement of touch signal lines is changed by forming them beneath planarization and bank layers, with touch electrodes connected through contact holes, allowing the lines to overlap the electrodes and extend from the display area to the non-display area, using the same metal material as the display pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch signal lines are disposed in the outer area (bezel area) to connect touch sensing electrodes, then the touch sensing function can be implemented, but the outer area size increases which is undesirable
Solution Approach 1:
The touch signal lines are moved from the planar outer area to the vertical dimension by disposing them beneath the planarization and bank layers. This allows the lines to overlap the touch electrodes in the thickness direction, effectively utilizing the Z-axis dimension to resolve the area conflict in the X-Y plane.
Solution Approach 2:
The touch signal lines are nested within the layered structure of the display panel, specifically positioned beneath the planarization layer and bank layer. This nesting approach allows the signal lines to occupy space within the existing layered architecture rather than requiring additional lateral space.
2Reliability
If touch signal lines are arranged in the outer area, then electrical connection to touch electrodes is achieved, but the bezel formation area increases
Solution Approach 1:
The signal lines transition from a lateral arrangement in the outer area to a vertical arrangement beneath the planarization and bank layers, maintaining electrical connectivity while eliminating the need for additional bezel formation area.
Solution Approach 2:
The touch signal lines are formed using the same metal material and process layer as the pixel electrodes, creating a consistent electrical connection structure that maintains reliability while optimizing space utilization.
3Adaptability or versatility
If touch signal lines are formed on a separate layer or with different material, then touch functionality is achieved, but device complexity increases
Solution Approach 1:
The metal process layer is designed to serve dual functions: forming both the pixel electrodes for display and the touch signal lines for touch sensing. This multi-functionality reduces device complexity by eliminating the need for separate dedicated touch signal line layers.
Solution Approach 2:
The touch signal lines are formed using the same metal material and fabrication process as the pixel electrodes, creating a homogeneous structure that simplifies manufacturing and reduces structural complexity compared to using different materials or processes.
Data Source
AI summary
A display device includes a display panel having a plurality of pixels disposed in a display area, a touch sensing unit having a plurality of touch electrodes arranged on a front surface of the display panel, and a touch driving circuit supplying driving signals to the touch electrodes through touch lines and detecting coordinates of a touch position of the touch sensing unit. The touch lines are formed and disposed in a rear surface direction of at least one touch electrode so as to overlap the at least one touch electrode of the touch electrodes. The touch electrodes are respectively connected to the touch lines through at least one touch contact hole, and the touch lines are formed of a same metal material on a same process layer as at least one electrode included in the plurality of pixels formed in the display area.