In-Cell Touch Display Driving Method for Uniform TFT Ageing
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Solution Overview
Problem
In in-cell type touch display panels, the existing driving methods cause uneven voltage stress on TFTs across GOA units, leading to abnormal displays and premature ageing due to differences in voltage holding time and electricity leakage.
Innovation Solution
A driving method that adjusts the timing of the touch scan signal to turn on during different frames, ensuring that GOA units finish outputting scan driver signals at varying stages, thereby distributing voltage stress uniformly across all stages, preventing excessive ageing and abnormal displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the touch scan signal is turned on at a fixed stage (n-th stage) in every frame, then the touch sensing operation is stable and simple to control, but the TFTs in different GOA units experience uneven voltage stress and ageing
Solution Approach 1:
The patent applies periodic action by alternating the touch scan signal activation stage between different frames. In even frames, the touch scan signal is activated at the n-th stage, while in odd frames, it is activated at a different stage. This periodic variation distributes the voltage stress uniformly across all GOA units over time, preventing localized ageing while maintaining overall system reliability.
2Duration of action of stationary object
If the touch scan signal is turned on at different stages in different frames, then the voltage stress is distributed uniformly across GOA units, but the control complexity increases
Solution Approach 1:
The patent implements periodic action by systematically alternating the touch scan signal activation between different stages in different frames. This regular pattern extends the lifespan of GOA units by distributing voltage stress uniformly, while the predictable alternation keeps the control method relatively simple and easy to implement.
3Reliability
If the first node voltage is held at high level for extended periods, then the scan driver signal can be maintained, but excessive voltage stress causes TFT ageing and abnormal displays
Solution Approach 1:
The patent applies periodic action by varying the touch scan signal activation stage across different frames, which periodically changes the voltage holding duration for different GOA units. This prevents any single unit from experiencing excessive continuous voltage stress, thereby maintaining display normality and preventing abnormal displays caused by TFT ageing.
Data Source
AI summary
The invention provides a driving method for in-cell type touch display panel, by setting the touch scan signal (TP SCAN) turns on when n-th stage GOA unit finishing outputting a scan driver signal (G(n)) during displaying m-th frame, and during displaying (m+1)-th frame, setting the touch scan signal (TP SCAN) turns on when any stage GOA unit other than the n-th stage finishing outputting a scan driver signal (G(n)). The driving method makes the TFTs in GOA unit of each stage withstanding the voltage stress time and the ageing extent uniform to avoid any single stage ageing faster than the remaining to cause abnormal display in the known technologies.