Touch Display Panel Common Electrode Shielding
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Solution Overview
Problem
Existing touch display devices face challenges in performing touch sensing independently of display driving, as display driving can degrade touch sensing performance and introduce noise in touch sensing signals, and this is often accompanied by an increase in the number of masks and load on touch lines.
Innovation Solution
A touch display panel and device design that includes a plurality of data lines, touch lines, common electrodes, and a touch load reducing layer, where the common electrode overlaps both the touch line and data line to shield the touch line from display driving signals, and a touch load reducing layer is used to minimize the load on touch lines, while preventing parasitic capacitance and display noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If touch sensing and display driving are performed simultaneously using the same display panel, then touch sensing can be performed independently, but noise in touch sensing signals is induced by display driving signals
Solution Approach 1:
A common electrode is introduced as an intermediary component between the touch line and data line. This common electrode acts as a shield that blocks electromagnetic interference from the data line, allowing touch sensing to operate independently without noise contamination from display driving signals.
Solution Approach 2:
The patent utilizes the electromagnetic field generated by display driving signals and converts it into a beneficial shielding effect. By positioning the common electrode to overlap with both the touch line and data line, the electromagnetic field from the data line creates a shielding effect that protects the touch line from external interference, turning potential harm into a protective mechanism.
2Object-affected harmful factors
If a shielding structure is added between touch line and data line, then noise is reduced, but the number of masks increases
Solution Approach 1:
The common electrode serves multiple functions simultaneously: it acts as a shield against electromagnetic interference, maintains electrical potential for touch sensing operation, and reduces parasitic capacitance between touch and display lines. This multi-functionality achieves noise reduction without requiring additional separate shielding structures or masks.
Solution Approach 2:
The patent merges the shielding function with the existing common electrode structure used in display panels. Instead of adding a separate shielding layer, the common electrode is configured to perform both its traditional role and the new shielding function, thereby reducing noise without increasing the number of masks.
3Adaptability or versatility
If touch electrodes are disposed on or embedded in the display panel, then touch sensing function is integrated, but display driving performance is degraded by touch sensing structure
Solution Approach 1:
The common electrode serves as an intermediary that electrically connects the touch line to the pixel electrode while maintaining proper isolation. This intermediary structure allows touch sensing signals to be transmitted without degrading display driving performance, as it provides a controlled electrical pathway that minimizes interference between touch and display functions.
Solution Approach 2:
The patent applies different electrical characteristics to different regions of the common electrode. In regions where the common electrode overlaps with the pixel electrode, it maintains display driving characteristics, while in regions where it overlaps with the touch line, it provides touch sensing characteristics with reduced parasitic capacitance. This local differentiation allows both functions to coexist without performance degradation.
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 design allows for simultaneous display driving and touch sensing, reduces noise in touch sensing signals, minimizes the increase in the number of masks, and protects display driving performance by reducing the load on touch lines, thereby enhancing overall touch sensing performance.
Implementation Method 1
a common electrode between the touch line and the data line such that the common electrode overlaps both the touch line and the data line
Implementation Method 2
prevent parasitic capacitance and display noise
Implementation Method 3
a touch load reducing layer between the touch line and the common electrode; wherein the touch line overlaps the touch load reducing layer and a width of the touch load reducing layer is wider than a widest width of the touch line
Data Source
AI summary
A touch display panel and device. A common electrode is provided between a display driving signal line and a touch line. The common electrode functions as a shielding pattern that prevents display noise of a touch sensing signal without increasing the number of masks used to form the touch display device. A touch load reducing layer is disposed in a region between the touch line and the common electrode, except for a region in which the common electrode and pixel electrodes overlap. This reduces the load of the touch line and improves touch sensing performance without having an adverse effect on display driving.