Touch Assistance Line for Display Edge Sensitivity
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Solution Overview
Problem
In display devices with integrated touch screens, edge touch electrodes experience reduced touch sensitivity and performance due to parasitic capacitance generated by nearby lines such as common voltage, high voltage, and ESD lines, which differ from center touch electrodes in signal characteristics.
Innovation Solution
A touch assistance line with the same phase and potential difference as the touch signal is disposed in a non-display area outside the display area, surrounding the touch electrodes, and supplies a touch assistance signal to gate and data lines during the touch sensing period, reducing parasitic capacitance and enhancing touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If touch electrodes are disposed at edge portions of the panel, then the display area is increased and user interface is improved, but parasitic capacitance is generated by nearby lines which reduces touch sensitivity
Solution Approach 1:
A touch assistance line is introduced as an intermediary element disposed between the edge touch electrode and the common voltage supply line/high voltage supply line/ESD line. This intermediary structure mediates the electromagnetic interaction by providing a shielding effect that reduces parasitic capacitance coupling between the touch electrode and nearby high-voltage lines, thereby improving touch sensitivity at edge portions without reducing display area.
Solution Approach 2:
The patent converts the harmful parasitic capacitance effect into a beneficial shielding mechanism. By disposing the touch assistance line near the edge touch electrode, the line acts as a shield that redirects electromagnetic fields, transforming the previously harmful parasitic capacitance into a protective shielding effect that enhances touch signal detection at panel edges.
2Measurement precision
If touch assistance signals are supplied to gate lines and data lines during touch sensing period, then touch sensitivity is enhanced by reducing parasitic capacitance, but signal interference may occur between display and touch functions
Solution Approach 1:
The patent implements periodic action by dividing operation into distinct display periods and touch sensing periods. During display periods, normal display signals are supplied to gate lines and data lines. During touch sensing periods, touch assistance signals are supplied instead. This periodic switching eliminates simultaneous signal conflicts, preventing interference while maintaining high touch sensitivity when touch measurement is performed.
Solution Approach 2:
The touch assistance signal is supplied in advance during the touch sensing period before actual touch detection occurs. This preliminary action prepares the electrical environment by establishing appropriate voltage levels on gate and data lines, thereby preemptively reducing parasitic capacitance effects before they can interfere with touch signal measurement, ensuring accurate touch sensitivity detection.
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 solution ensures equivalent signal characteristics for edge and center touch electrodes, improving touch sensitivity and performance by eliminating the influence of parasitic capacitance and allowing for consistent touch sensing across the display device.
Implementation Method 1
edge touch electrodes experience reduced touch sensitivity and performance due to parasitic capacitance generated by nearby lines
Data Source
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AI summary
Disclosed are a display device, in which a touch assistance line (800) to which a touch assistance signal (TAS) having the same phase and potential difference as those of a touch signal (TS) is supplied during a touch sensing period (T) is disposed in a panel (100), and a driving method thereof.