Touch Sensor Electrode Frequency Control for Display Noise
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Solution Overview
Problem
Conventional touch sensors face interference from display functions, disrupting touch position recognition in display panels used in smart devices.
Innovation Solution
A touch sensor system comprising electrically separated sensing electrodes and a touch controller that adjusts driving signal frequencies based on predetermined conditions, allowing for independent operation of touch position recognition without interfering with display functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If sensing electrodes share common electrical connection with display pixels, then device complexity is reduced, but touch position recognition is disturbed by display function interference
Solution Approach 1:
The sensing electrodes are electrically separated into independent groups (first sensing electrode group and second sensing electrode group) with separate driving signal lines and sensing signal lines. This segmentation allows independent control and sensing for each electrode group, preventing interference from display functions while maintaining structural organization.
Solution Approach 2:
The sensing function is extracted from the display pixel structure by providing separate driving signal lines and sensing signal lines for sensing electrodes. This extraction removes the harmful coupling between display and touch functions, allowing each function to operate independently without mutual interference.
2Ease of operation
If uniform driving frequency is applied to all sensing electrodes, then control simplicity is maintained, but momentary noise from display operations interferes with touch sensing
Solution Approach 1:
Different driving frequencies are applied to different sensing electrode groups based on their local requirements. The first sensing electrode group receives driving signals at a first frequency while the second sensing electrode group receives driving signals at a second frequency, allowing optimization for local noise conditions and improving overall noise immunity.
Solution Approach 2:
The driving frequency for sensing electrodes is made dynamic rather than uniform. The system can adjust frequencies differently for different electrode groups based on display operation conditions, enabling adaptive noise reduction while maintaining control flexibility.
3Measurement precision
If high driving frequency is applied to all sensing electrodes continuously, then touch sensing accuracy is improved, but power consumption increases
Solution Approach 1:
Driving signals are applied periodically to sensing electrodes rather than continuously, with different frequencies for different electrode groups. This periodic action maintains touch sensing capability while reducing overall power consumption compared to continuous high-frequency driving of all electrodes.
Solution Approach 2:
The driving frequency parameter is changed and optimized for different sensing electrode groups based on their specific requirements. By adjusting frequencies rather than using a uniform high frequency for all electrodes, the system achieves adequate sensing accuracy with reduced power consumption.
Data Source
AI summary
A touch sensor includes sensing electrodes and a touch controller. The sensing electrodes are electrically separated from each other, the sensing electrodes including a first sensing electrode and a second sensing electrode. The touch controller is configured to provide driving signals to the sensing electrodes, to receive sensing signals from the sensing electrodes, and to determine a touch position based on the sensing signals. The touch controller is further configured to, in response to reception of a frequency increase signal including information about the first sensing electrode, set a frequency of a driving signal provided to the first sensing electrode as a first frequency, and to set a frequency of a driving signal provided to the second sensing electrode as a second frequency different than the first frequency.