In-Cell Display Touch Driving Method for Stray Capacitance
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Solution Overview
Problem
In in-cell display modules, the touch electrode's reuse as a common electrode leads to stray capacitance between the touch electrode and the gate and data lines, limiting touch sensitivity due to signal-to-noise ratio issues, and increasing the active level of the uplink signal for better signal transmission results in higher power consumption and potential negative effects on refresh frequency.
Innovation Solution
The method involves providing a touch signal with a higher active level uplink signal in the first touch sub-stage and a lower active level touch driving signal in the second touch sub-stage, using a modulation signal to independently control these signals, and applying signals with the same waveform to the gate and data lines to reduce stray capacitance effects, thereby improving touch sensitivity and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the active level of the uplink signal is increased to improve signal transmission quality, then the signal-to-noise ratio is improved, but the power consumption increases
Solution Approach 1:
The touch stage is divided into two sub-stages: a first touch sub-stage for providing the uplink signal with higher active level to improve signal-to-noise ratio, and a second touch sub-stage for providing the touch driving signal with lower active level to reduce power consumption. This temporal segmentation allows the system to achieve both high signal quality and low power consumption by using high power only when necessary for uplink transmission.
2Device complexity
If the touch electrode is reused as a common electrode to integrate touch and display functions, then the device complexity is reduced, but the touch sensitivity is limited due to stray capacitance
Solution Approach 1:
Before providing the touch driving signal in the second touch sub-stage, the method applies signals with the same waveform as the touch signal to the gate lines and data lines in advance. This preliminary action compensates for the stray capacitance effects between the touch electrode and the gate/data lines, thereby improving touch sensitivity while maintaining the integrated electrode structure.
Solution Approach 2:
The method changes the waveform parameters of signals applied to gate lines and data lines during the touch stage, making them match the touch signal waveform. This parameter change helps to cancel out the stray capacitance effects and improve touch sensitivity without requiring separate touch and common electrodes.
3Measurement precision
If signals are applied to gate lines and data lines during touch stage to reduce stray capacitance effects, then the touch sensitivity is improved, but the device complexity increases
Solution Approach 1:
The method merges the touch signal processing with the existing display signal pathways by applying the same waveform signals to gate lines and data lines that are already part of the display driving circuitry. This combining approach improves touch sensitivity without requiring separate dedicated circuits, thereby limiting the increase in device complexity.
Data Source
AI summary
The present disclosure provides a method for driving a display panel, a display module and a display device. The display panel includes a touch electrode. The method includes: in a touch stage, providing a touch signal to the touch electrode. The touch stage includes: a first touch sub-stage and a second touch sub-stage spaced from each other; the touch signal includes: an uplink signal and a touch driving signal, and an active level of the uplink signal is higher than an active level of the touch driving signal. In the first touch sub-stage, the uplink signal is provided to the touch electrode; and in the second touch sub-stage, the touch driving signal is provided to the touch electrode.