Touch Sensor Driving in Display Panels With Constant Report Rate
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Solution Overview
Problem
Existing display apparatuses face challenges in optimizing touch-sensing performance, particularly in balancing display modes to maintain consistent touch report rates and efficient power consumption.
Innovation Solution
The display apparatus incorporates a touch sensor with first and second touch electrodes, driven by a display driver and a touch sensor driver, utilizing distinct driving signals with varying voltages, frequencies, and waveforms in different display modes to optimize touch-sensing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the display apparatus uses a single driving signal for the touch sensor across all display modes, then the device complexity is reduced, but the touch-sensing performance and power efficiency deteriorate
Solution Approach 1:
The patent implements dynamic switching between different driving signals (first, second, and third driving signals) based on the display mode. The touch sensor driver selectively applies different driving voltages and sampling configurations depending on whether the display is in first or second mode, allowing the system to adapt to varying performance requirements while maintaining optimal touch sensing accuracy and power efficiency
Solution Approach 2:
The patent changes multiple parameters of the driving signal including voltage levels (first driving voltage, second driving voltage, third driving voltage), sampling rates, and waveform characteristics. By adjusting these parameters according to display mode, the system optimizes touch sensing performance for different operational conditions without requiring complete hardware redesign
2Measurement precision
If the touch sensor driver increases sampling number during second scan periods, then the touch-sensing accuracy is improved, but the power consumption increases
Solution Approach 1:
The patent applies partial action by increasing the sampling number only during specific second scan periods when high touch sensing accuracy is required, rather than continuously maximizing sampling throughout all periods. This selective approach maintains measurement precision when needed while avoiding unnecessary power consumption during periods where reduced sampling is acceptable
Solution Approach 2:
The patent implements periodic variation in sampling number, alternating between higher sampling during second scan periods and lower sampling during first scan periods. This periodic modulation of sampling intensity allows the system to achieve adequate touch sensing accuracy over time while significantly reducing average power consumption compared to continuous high-rate sampling
3Productivity
If the display apparatus maintains consistent touch report rate across different display modes, then the touch responsiveness is improved, but the device complexity increases
Solution Approach 1:
The patent employs feedback mechanisms where the touch sensor driver continuously monitors the current display mode and dynamically adjusts driving signal parameters to maintain consistent touch report rate. The system receives feedback about display mode changes and automatically compensates by modifying sampling numbers and driving voltages, ensuring stable touch responsiveness without manual intervention
Solution Approach 2:
The patent creates a universal touch sensing framework that operates consistently across multiple display modes through a single integrated driving signal configuration. The touch sensor driver is designed to handle both first and second display modes using the same hardware infrastructure, selectively applying different signal parameters to achieve mode-independent touch report rate consistency
Data Source
AI summary
Provided is a display apparatus including pixels, a touch sensor above the pixels, and including first touch electrodes and second touch electrodes, a display driver configured to drive the pixels in a first display mode in which a frame includes a first scan period, or in a second display mode in which another frame includes the first scan period and one or more second scan periods, and a touch sensor driver configured to supply a first driving signal to the touch sensor in the first display mode, and supply a second driving signal to the touch sensor during the first scan period, and supply a third driving signal to the touch sensor during the one or more second scan periods, in the second display mode, wherein a touch report rate of the touch sensor driver is the same in the first display mode and in the second display mode.