Touch Panel Driving Modes for Fast, Low-Noise Touch Sensing
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Solution Overview
Problem
Existing touch panels face challenges in simultaneously achieving low noise interference and high touch report rates, which affect the accuracy and speed of touch detection.
Innovation Solution
A display device with a touch panel and driver that employs multiple driving modes and sensing periods to optimize touch detection, including self-sensing, touch sensing, and noise sensing, while reducing noise interference and increasing touch report rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the touch report rate is increased to improve response speed, then the response speed to touch is improved, but noise interference increases which decreases touch detection accuracy
Solution Approach 1:
The sensing period is divided into multiple sub-periods (first sensing period, second sensing period, third sensing period) with different driving schemes. During the first sensing period, touch driving signals are provided to all touch electrodes to detect touch events. During the second sensing period, touch driving signals are provided to only a subset of touch electrodes (e.g., every other electrode) to reduce noise while maintaining touch detection capability. This segmented approach allows the system to achieve high touch report rates while minimizing noise interference through selective electrode activation.
2Area of stationary object
If touch driving signals are provided to all touch electrodes simultaneously, then complete touch area coverage is achieved, but noise interference increases
Solution Approach 1:
The system employs periodic switching between different driving schemes. In the first sensing period, all touch electrodes are activated to ensure complete area coverage. In the second sensing period, only a subset of electrodes is activated to reduce noise. This periodic alternation between full-coverage mode and reduced-noise mode allows the system to maintain comprehensive touch area coverage while periodically minimizing noise interference through selective electrode deactivation.
3Measurement precision
If the sensing period is extended to improve touch detection accuracy, then measurement precision is improved, but the touch report rate decreases
Solution Approach 1:
The system dynamically adjusts the sensing scheme based on detected touch events. When a touch event is detected during the first sensing period, the system transitions to the second sensing period with reduced electrode activation to minimize noise during measurement. This dynamic adaptation allows the system to achieve high touch detection accuracy by extending the effective sensing time through multiple periods while maintaining high touch report rates through efficient use of touch-driving signals during each period.
Data Source
AI summary
A display device includes: a touch panel including a touch area including first touch electrodes and second touch electrodes; and a touch panel driver for providing touch driving signals to the first touch electrodes. The touch panel driver provides the touch driving signals to the first touch electrodes in a first touch sensing period of a first mode, operates in a second mode when the first touch is detected, and provides the touch driving signals to the first touch electrodes disposed in a first row area of the touch area in which the first touch is detected in a second touch sensing period of the second mode.