In-cell Touch Display Gate Line Driving Parasitic Capacitance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In-cell touch display devices face issues with parasitic capacitance, which increases the load of touch operations, lowers accuracy, and can make touch sensing impossible, particularly in in-cell display devices using capacitive touch sensing technology.
Innovation Solution
The implementation of a gate line driving system that includes a level shifter generating a load-free driving signal, a multiplexer inputting scanning voltage or load-free driving signals based on the driving mode, and a micro control unit managing timing signals to prevent parasitic capacitance without altering the design of existing components like the gate driver and power management integrated circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitive touch sensing technology is used in in-cell display devices, then touch sensing capability is provided, but parasitic capacitance increases the load of touch operations and lowers accuracy
Solution Approach 1:
The patent applies equipotentiality by setting the gate line voltage to match the touch electrode voltage during touch operations. This creates an equipotential condition between the gate lines and touch electrodes, eliminating voltage differences that would otherwise generate parasitic capacitance. The gate driver is configured to output a gate line voltage equal to the touch electrode voltage when touch mode is activated, thereby preventing parasitic capacitance formation while maintaining touch sensing accuracy and reducing operational load.
2Ease of operation
If gate driver outputs scanning signal to gate lines during touch mode, then gate lines are driven, but parasitic capacitance is generated between gate lines and touch electrodes
Solution Approach 1:
The patent applies dynamics by making the gate driver's output voltage dynamic and adaptive based on the operating mode. The gate driver automatically adjusts its output voltage level: during display mode, it outputs scanning signals with varying voltages to drive the display; during touch mode, it outputs a constant voltage equal to the touch electrode voltage to prevent parasitic capacitance. This dynamic adaptation allows the same gate driver to serve dual functions without generating harmful parasitic effects.
3Adaptability or versatility
If touch electrodes and data lines are integrated in in-cell technology, then in-cell display device is achieved, but parasitic capacitance makes touch sensing impossible in severe cases
Solution Approach 1:
The patent applies equipotentiality to the integrated structure by ensuring that the gate lines, which are closely coupled with touch electrodes in the in-cell configuration, are maintained at the same potential as the touch electrodes during touch operations. This eliminates the voltage differential that would create parasitic capacitance between the integrated components, thereby preserving touch sensing accuracy despite the close integration of data lines and touch electrodes in the in-cell architecture.
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 effectively prevents parasitic capacitance, ensuring accurate and reliable touch sensing in in-cell touch display devices by optimizing the gate line driving system, thereby enhancing the efficiency of touch operations without modifying existing hardware.
Implementation Method 1
undesirable parasitic capacitance is generated by other voltage lines or electrodes surrounding touch electrodes
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An in-cell touch display device (100). A panel (110) has a plurality of data lines (DL), a plurality of gate lines (GL) and a plurality of touch electrodes disposed thereon. A touch driving signal (TDS) is applied to the plurality of touch electrodes when a driving mode is a touch mode. A data driver (120) drives the plurality of data lines (DL). A gate driver (130) drives the plurality of gate lines (GL). The gate driver (130) sequentially outputs a scanning signal for driving the plurality of gate lines (GL) to the plurality of gate lines (GL) when the driving mode is a display mode, and outputs a load-free driving signal (LFDS_gate) corresponding to the touch driving signal (TDS) to at least one gate line (GL) when the driving mode is the touch mode. A level shifter (810) generates the load-free driving signal (LFDS_gate). A multiplexer (820) inputs a scanning voltage (VGH/VGL) or the load-free driving signal (LFDS_gate) to the gate driver (130) depending on the driving mode.