Touch Sensor Routing Structure for Narrow-Bezel Display Panels
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Solution Overview
Problem
Existing display devices face challenges in reducing bezel size while maintaining high touch sensitivity and minimizing noise between sensor electrodes.
Innovation Solution
A display device and panel design featuring a touch sensor structure with multiple sensor electrodes and routing lines in different metal layers, allowing for a narrow bezel and improved touch sensitivity, with internal touch routing lines that do not pass through the non-display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the bezel size is reduced, then the display area ratio is improved, but the touch sensitivity and signal stability deteriorate due to limited space for sensor electrodes and routing lines
Solution Approach 1:
The patent transitions from planar routing to three-dimensional vertical stacking by placing sensor electrodes and routing lines in multiple metal layers (first, second, and third metal layers). This vertical dimension allows the touch sensor structure to accommodate more components without increasing the horizontal bezel size, thereby maintaining touch sensitivity while reducing the bezel area ratio.
Solution Approach 2:
The sensor electrode is divided into multiple sub-sensor electrodes (first sub-sensor electrode, second sub-sensor electrode, etc.) that are electrically connected through bridges. This segmentation allows the sensor electrode to extend across a larger effective area while being routed through multiple layers, maintaining signal strength and touch sensitivity despite the reduced bezel size.
2Ease of manufacture
If routing lines pass through the non-display area, then the connection is simplified, but the noise between sensor electrodes increases
Solution Approach 1:
The routing lines are distributed across multiple metal layers (first, second, and third metal layers) rather than being confined to a single plane. This vertical separation reduces electromagnetic coupling and noise between adjacent routing lines and sensor electrodes, while still achieving simple connections through the non-display area.
Solution Approach 2:
The bridges serve as intermediary connection elements that electrically connect sub-sensor electrodes while being positioned in specific metal layers. These bridges act as controlled impedance pathways that minimize noise coupling between different sensor electrode segments while maintaining electrical continuity.
3Reliability
If multiple sensor electrodes are added to improve touch sensitivity, then the touch response is enhanced, but the device complexity increases
Solution Approach 1:
Multiple sensor electrodes and their corresponding routing lines are stacked vertically across different metal layers. This three-dimensional arrangement allows multiple sensor elements to be integrated without proportionally increasing the horizontal footprint or planar complexity, as the additional elements are arranged in the vertical dimension.
Solution Approach 2:
The metal layers serve multiple functions: the first metal layer contains sensor electrodes and routing lines, the second metal layer contains bridges and additional routing lines, and the third metal layer contains further routing lines. This multi-functional layering reduces the overall structural complexity by consolidating multiple components into shared structural elements.
Data Source
AI summary
A display device can include a display area and a non-display area, a plurality of first sensor electrodes disposed in the display area, a plurality of second sensor electrodes disposed in the display area, a plurality of first pads disposed in the non-display area, a plurality of second pads disposed in the non-display area, a plurality of first touch routing lines electrically connecting the plurality of first sensor electrodes with the plurality of first pads, and a plurality of second touch routing lines electrically connecting the plurality of second sensor electrodes with the plurality of second pads. Also, one of the plurality of first touch routing lines electrically connected to at least one of the plurality of first sensor electrodes overlaps with at least another one of the plurality of first sensor electrodes that is electrically connected to another first touch routing line.