Pixel Array Touch Crosstalk Mitigation via Luminance Compensation
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Solution Overview
Problem
Integrated display and touch subsystems in electronic devices experience crosstalk issues, such as Impedance-based Display-Touch Crosstalk (Impedance DTX) and Switching-based Display-Touch Crosstalk (Switching DTX), leading to inaccurate touch sensing and inefficient resource allocation.
Innovation Solution
The systems and methods mitigate crosstalk by determining cathode impedance during touch scans and using image processing systems to calculate pixel luminance values and global brightness values to estimate cathode current, and by compensating for Switching DTX through gate clock and data line toggling information, allowing for the cancellation of undesired crosstalk components in touch sensing signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If display and touch subsystems are integrated in the same panel, then device complexity is reduced and manufacturing is simplified, but crosstalk between the subsystems occurs leading to inaccurate touch sensing
Solution Approach 1:
The patent segments the touch sensing process into multiple phases: a first touch scan phase during which display image data is presented, and a second touch scan phase during which a reference touch sensing signal is generated. By separating the measurement of touch signals from the display operation in time, the patent eliminates crosstalk while maintaining integration. The controller selectively generates touch sensing signals during intervals when display signals are not actively driving pixels, thus preventing impedance interference.
Solution Approach 2:
The patent performs preliminary characterization of the display subsystem's impedance characteristics before conducting accurate touch sensing. The system measures impedance values at multiple gray level settings and stores this calibration data. During operation, the system uses this pre-characterized impedance information to compensate for or eliminate crosstalk effects, enabling accurate touch sensing even in the presence of an integrated display subsystem.
2Productivity
If touch sensing scans are performed at high frequency, then touch responsiveness is improved, but power consumption increases due to repeated impedance variations
Solution Approach 1:
The patent implements periodic touch scanning with variable duty cycles. Instead of continuous high-frequency scanning, the system performs touch scans at optimized intervals and adjusts the scanning duty cycle based on operational needs. The controller can reduce touch scan frequency during periods of low user interaction while maintaining high-frequency capability when responsiveness is critical, thus balancing power consumption with touch responsiveness requirements.
Solution Approach 2:
The patent dynamically adjusts touch sensing parameters including scan frequency, signal amplitude, and integration time based on display content and operational context. When the display is showing static content or during low-activity periods, the system reduces touch scan frequency to save power. When dynamic content is displayed or user interaction is detected, the system increases scan frequency to maintain responsiveness, optimizing the balance between power consumption and 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
This approach improves touch processing performance, reduces power consumption, and enables higher touch frequency operations by accurately compensating for crosstalk, enhancing user experience and device performance across various electronic devices.
Implementation Method 1
a parasitic coupling path may form between a pixel layer and a touch sensing electrode layer
Data Source
AI summary
Systems, methods, and devices are described that may mitigate pixel and touch crosstalk noise. A touch processing system may compensate touch scan data to reduce the noise based on a luminance value. An image processing system may determine the luminance value based on image data and a display brightness value of an electronic display. Using the compensated touch scan data, the touch processing system may determine a proximity of a capacitive object to at least one touch sense region of the electronic display.