Shift Register Potential Hold Circuit for Touch Display Noise Reduction
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Solution Overview
Problem
In touch display panels, the potential of the pulling-up node in shift registers can be attenuated due to longer time durations of touch control periods, leading to attenuation of the gate-on signal and abnormal display issues.
Innovation Solution
A shift register design incorporating a first inputting circuit, a second inputting circuit, an outputting circuit, a node controlling circuit, a potential hold circuit, and an output-noise reduction circuit, which includes transistors and capacitors to maintain stable potential and reduce noise, ensuring continuous charging of the pulling-up node and noise reduction during touch control periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch control period is inserted between gate-on signal output from adjacent shift registers, then touch control function is enabled, but the potential of the pulling-up node is attenuated due to leakage current during the longer time duration
Solution Approach 1:
The patent applies preliminary action by proactively compensating for potential attenuation before it affects the gate-on signal output. The shift register circuit is designed to predict and counteract the leakage current effect during the touch control period, ensuring the pulling-up node potential remains sufficient to drive the next gate-on signal without degradation.
Solution Approach 2:
The patent changes the electrical parameters of the shift register circuit, specifically adjusting the charging capacity and voltage levels to account for the extended touch control period. By modifying these parameters, the circuit maintains adequate potential at the pulling-up node despite the increased time duration and associated leakage current.
2Measurement precision
If the time duration of touch control period is increased, then touch control precision is improved, but leakage current increases causing potential attenuation at the pulling-up node
Solution Approach 1:
The patent implements beforehand cushioning by designing the shift register with sufficient charging capacity and voltage headroom to compensate for the cumulative leakage current over the extended touch control period. This cushioning effect ensures that even with increased time duration for higher precision touch control, the potential attenuation is prevented.
3Reliability
If the potential of the pulling-up node is attenuated, then the gate-on signal output is weakened, but TFTs may fail to turn on causing display abnormalities
Solution Approach 1:
The shift register circuit performs self-service by automatically compensating for its own potential attenuation through integrated charging and voltage maintenance mechanisms. The circuit monitors and adjusts its internal state to ensure the pulling-up node maintains sufficient potential, eliminating the need for external intervention or additional complex control circuits.
Data Source
AI summary
A shift register, a gate driving circuit and a display device are disclosed. The shift register includes a first inputting circuit, a second inputting circuit, an outputting circuit, a node controlling circuit, a potential hold circuit and an output-noise reduction circuit. The first inputting circuit and the second inputting circuit are to implement inputting to the first node and resetting of the first node. The node control circuit controls potentials of the first node and the second node. The outputting circuit controls the signal of the signal outputting terminal under control of the first node and the second node. The potential hold circuit can continuously charge the first node within a touch control period. The output-noise reduction circuit can perform noise reduction for the signal outputting terminal in the touch control period.