Touch Driving Electrode Segmentation for LCD Touch Accuracy
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Solution Overview
Problem
Mutual-capacitive touch screens embedded in LCDs face accuracy issues in detecting finger touches due to deflections of liquid crystal molecules affecting capacitance values, making it difficult to distinguish between finger touches and molecular deflections.
Innovation Solution
Divide touch driving electrodes into N portions perpendicular to gate lines, reset pixels to a same grey scale value before touch driving, and synchronize touch driving and display scanning time periods to ensure all liquid crystal molecules are in a consistent deflection state, minimizing the impact of molecular deflections on capacitance measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If mutual-capacitive touch screen is embedded in LCD, then light transmissibility is improved and thickness is reduced, but touch detection accuracy deteriorates due to liquid crystal molecule deflections affecting capacitance values
Solution Approach 1:
The touch driving electrodes are divided into N portions, with each portion independently controlled. This segmentation allows different regions to be reset at different times, enabling the system to stabilize liquid crystal molecules in each region before performing capacitance measurements, thereby improving touch detection accuracy while maintaining the embedded LCD structure
Solution Approach 2:
The patent applies a reset signal to pixels before performing touch detection in each region. This preliminary action stabilizes the liquid crystal molecules and establishes a consistent baseline capacitance value, allowing the system to distinguish between baseline variations and actual touch-induced capacitance changes, thus improving measurement precision
2Measurement precision
If pixels are reset before touch driving, then liquid crystal molecules are stabilized and touch detection accuracy is improved, but display updating time increases
Solution Approach 1:
By dividing the display into N portions and processing them sequentially, the patent can perform reset operations and touch detection in an interleaved manner. While one portion is being reset, other portions can be updated for display, thereby distributing the time cost across multiple regions and minimizing the overall impact on display updating time
Solution Approach 2:
The patent implements periodic reset signals that are synchronized with the touch detection process. By periodically resetting pixels in a coordinated manner with display updates, the system ensures liquid crystal stability during measurement while maintaining efficient display refresh cycles, balancing accuracy improvement with time efficiency
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
Improves the accuracy of touch detection by stabilizing liquid crystal molecules, reducing errors caused by deflections, and maintaining display quality by minimizing the resetting time.
Implementation Method 1
capacitance values of the mutual capacitors are changed, i.e. dielectric coefficients of dielectrics between the touch driving electrodes and the touch sensing electrodes are changed when the liquid crystal molecules at a position are deflected
Data Source
AI summary
The present disclosure provides in some embodiments a display substrate having a touch function, a method for driving the display substrate and a display apparatus. The method includes steps of: dividing touch driving electrodes included in the display substrate and parallel to gate lines into N portions, wherein each portion of the touch driving electrodes is arranged in a direction perpendicular to the gate lines, and N is a positive integer greater than or equal to 2; and resetting pixels corresponding to an nth portion of the touch driving electrodes before a touch driving for the nth portion is started, so that the pixels have a same grey scale value, wherein n is a positive integer greater than or equal to 1 and less than or equal to N.