In-Cell Touch Driving Detection Against Ghost Touches
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Solution Overview
Problem
Display devices with touch functionality are prone to noise interference, such as static electricity, leading to ghost touches and touch insensitivity due to missed touch sensing signals, which affect touch recognition and operation reliability.
Innovation Solution
A touch driving device with a controller that allocates detection periods within dummy periods to detect abnormal signals like static electricity, ignoring or resetting touch sensing signals during these periods to prevent malfunction and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the controller continuously monitors touch sensing signals during data periods, then touch recognition accuracy is improved, but the system becomes vulnerable to noise such as static electricity that can be misinterpreted as touch signals
Solution Approach 1:
The patent divides the monitoring period into distinct segments: a detection period specifically for detecting abnormal signals like static electricity, and a data period for collecting touch sensing signals. This segmentation allows the system to differentiate between normal touch signals and noise, preventing misinterpretation while maintaining touch recognition accuracy.
Solution Approach 2:
The system performs preliminary detection of abnormal signals during the detection period before the data period begins. By detecting static electricity or other noise in advance, the controller can prevent these abnormal signals from being misinterpreted as touch inputs during subsequent data collection, thereby improving measurement precision while reducing noise vulnerability.
2Productivity
If the controller waits until the next data period to detect an abnormal signal, then touch sensing can continue uninterrupted, but touch sensing signals become mixed between periods causing ghost touches or touch insensitivity
Solution Approach 1:
The patent segments the operational cycle into a detection period followed by a data period. This segmentation allows the system to detect abnormal signals when the panel is in a known safe state (during detection period) and then use this information to filter touch sensing signals during the subsequent data period, preventing signal mixing while maintaining continuous operation.
Solution Approach 2:
The controller uses feedback from the detection period to influence data processing during the data period. When an abnormal signal is detected during the detection period, the controller adjusts its behavior during the following data period (e.g., by ignoring certain signals or resetting the touch driving device), thereby maintaining reliability without interrupting continuous touch sensing productivity.
3Reliability
If the controller ignores all touch sensing signals during a detected abnormal period, then noise interference is eliminated, but legitimate touch inputs may be lost
Solution Approach 1:
The patent segments the time period into a detection period (when the panel is vulnerable to noise) and a data period (when touch sensing occurs). By restricting abnormal signal detection to the detection period and using this information to filter only the affected data period, the system achieves reliable noise filtering while minimizing loss of legitimate touch inputs that occur during normal data collection periods.
Data Source
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AI summary
The touch driving device can include a controller that detects an abnormal signal on a panel during a detection period. The touch driving device can be driven in time division using an in-cell touch method. When allocating dummy periods and data period to be located alternately, the detection period can be allocated within the dummy period. Not only can touch malfunctions be prevented through detection of the abnormal signal, but the occurrence of ghost touches or touch insensitivity phenomenon can be fundamentally blocked, thereby improving product reliability.