In-Cell Touch Display Driving Pulse Overdriving
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Solution Overview
Problem
In display devices with integrated in-cell type touch screens, the distance from the circuit unit affects the driving pulse delay, reducing the charging rate and leading to decreased touch signal levels and performance deviations in touch driving areas.
Innovation Solution
Applying overdriving and under-driving voltages to the driving pulse to reduce the time constant and enhance the charging rate, thereby improving touch performance by adjusting the voltage levels and application times for each driving electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driving pulse is applied to common electrodes corresponding to a touch driving area, then each common electrode can perform a function of a touch electrode, but as the distance becomes farther away from the circuit unit, the driving pulse is delayed, the time constant increases, and the charging rate is reduced
Solution Approach 1:
The patent applies different voltage levels (overdriving voltage for electrodes farther from the circuit unit, normal driving voltage for electrodes closer) to different locations of the driving electrodes. This local differentiation compensates for the distance-related signal degradation, ensuring consistent touch performance across all electrode regions.
Solution Approach 2:
The patent changes the voltage parameter of the driving pulse dynamically based on the electrode's distance from the circuit unit. By adjusting the voltage level (overdriving vs. normal driving voltage), the system compensates for the increased time constant and reduced charging rate in distant electrodes, maintaining uniform touch sensitivity across the display.
2Reliability
If the driving pulse time constant increases due to distance from the circuit unit, then the charging rate is reduced, but maintaining a consistent charging rate across all touch driving areas is necessary for uniform touch performance
Solution Approach 1:
The patent implements location-dependent voltage application where electrodes at different distances from the circuit unit receive different voltage levels. This local quality adjustment compensates for the distance-induced time delay, ensuring that all electrodes achieve consistent charging rates despite varying propagation distances.
Solution Approach 2:
The patent applies overdriving voltage as a preliminary compensatory measure to electrodes that will experience greater delay. By preemptively increasing the voltage for distant electrodes, the system counteracts the anticipated time constant increase and charging rate reduction, maintaining uniform touch performance.
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
The application of overdriving and under-driving voltages to the driving pulse in display devices with integrated touch screens enhances touch sensitivity and reduces performance deviations, improving overall touch performance by maintaining a consistent charging rate across the screen.
Implementation Method 1
a driving pulse, to which an overdriving voltage and an under-driving voltage are applied, is applied to a driving electrode, thereby enhancing a charging rate based on the driving pulse
Data Source
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AI summary
Disclosed is a display device with integrated touch screen (110). The display device includes a panel (100) configured to include a plurality of driving electrodes (112) and a plurality of sensing electrodes (114) and a display driver IC (200) configured to apply a common voltage to the plurality of driving electrodes (112) and the plurality of sensing electrodes (114) when the panel (100) operates in a display driving mode, and when the panel (100) operates in a touch driving mode, generate a driving pulse, which includes a maximum voltage with an overdriving voltage applied thereto and a minimum voltage with an under-driving voltage applied thereto, according to a timing pulse to apply the driving pulse to the plurality of driving electrodes (112), and respectively receive a plurality of sensing signals from the plurality of sensing electrodes (114).