In-Cell Touch Panel Driving Method for Visual Jitter Elimination
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Solution Overview
Problem
In-cell capacitive touch panels experience optical characteristic changes before and after touch operations, leading to visual jitters and afterimages, which deteriorate display quality due to the influence of touch scan signals on the common voltage and electric field.
Innovation Solution
A driving method and device that input touch scan signals of opposite polarity during two touch periods before and after the display period, ensuring these signals are symmetric with respect to the common voltage, thereby canceling their influence on the common voltage and electric field, eliminating extra liquid crystal deflection and visual issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch scan signals are input during touch periods, then touch detection function is enabled, but optical characteristic changes occur leading to visual jitters and afterimages
Solution Approach 1:
The patent applies preliminary anti-action by inputting a first touch scan signal during a first touch period before the display period, and then inputting a second touch scan signal with opposite polarity during a second touch period after the display period. This pre-compensation approach counteracts the influence of touch scan signals on the common voltage signal and electric field before they can cause visual jitters and afterimages during the display period, thereby eliminating extra liquid crystal deflection while maintaining touch detection functionality
Solution Approach 2:
The patent converts the harmful influence of touch scan signals on the common voltage and electric field into a beneficial effect by using opposite polarity signals. The second touch scan signal with opposite polarity compensates for the voltage changes caused by the first touch scan signal, transforming the potential harm (visual jitters) into a benefit (stable display quality) while preserving touch detection capability
2Ease of operation
If touch scan signals influence common voltage and electric field, then touch detection is achieved, but display quality deteriorates due to extra liquid crystal deflection
Solution Approach 1:
The patent implements preliminary anti-action by applying compensation signals before the display period. The first touch scan signal is input during a first touch period before the display period, and the second touch scan signal with opposite polarity is input during a second touch period after the display period. This pre-compensation eliminates the influence of touch scan signals on the common voltage signal and electric field during the display period, preventing extra liquid crystal deflection and maintaining high display quality while enabling touch detection
Solution Approach 2:
The patent applies parameter changes by varying the polarity of touch scan signals. The first touch scan signal and the second touch scan signal have opposite polarities, which changes the electrical parameters (voltage polarity) to compensate for the influence on the common voltage signal and electric field. This parameter variation allows touch detection to function while maintaining stable display characteristics by canceling out unwanted electrical influences
Data Source
AI summary
A driving method and a driving device for a touch panel are disclosed. The driving method of a touch panel comprises: inputting a first touch scan signal to a touch electrode during a first touch period before a display period; and inputting a second touch scan signal to the touch electrode during a second touch period after the display period, the first touch scan signal and the second touch scan signal being opposite in polarity.