Shift Register Pull-Up Voltage Stabilization for Uniform AMOLED Pulses
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Solution Overview
Problem
The waveforms of display driving pulses output by different driving output circuits in a shift register circuit of an active matrix organic light-emitting diode (AMOLED) panel differ due to voltage fluctuations at the pull-up node, leading to inconsistencies in the driving process and resulting in horizontal stripes on the display panel.
Innovation Solution
Incorporation of first and second pull-up voltage stabilizing circuits in the shift register unit to maintain the voltage at the pull-up node unchanged during specific periods, ensuring consistent output of display driving pulses across all driving output circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple driving output circuits operate sequentially in the shift register circuit, then the display driving pulses can be output continuously, but the voltage at the pull-up node fluctuates causing waveform inconsistencies
Solution Approach 1:
The patent introduces a pull-up voltage stabilizing circuit as an intermediary component between the driving output circuits and the pull-up node. This stabilizing circuit actively compensates for voltage fluctuations at the pull-up node by detecting voltage changes and applying corrective current, thereby maintaining stable pull-up voltage throughout the sequential operation of multiple driving output circuits and ensuring consistent waveform output.
2Device complexity
If the shift register circuit operates without voltage stabilization, then the circuit structure remains simple, but horizontal stripes appear on the display panel due to voltage fluctuations
Solution Approach 1:
The pull-up voltage stabilizing circuit implements a feedback mechanism by continuously monitoring the voltage at the pull-up node and adjusting its output current accordingly. When voltage deviation is detected, the stabilizing circuit generates corrective signals to restore the voltage to its nominal value, creating a closed-loop control system that actively suppresses voltage fluctuations and prevents horizontal stripe defects while maintaining relatively simple circuit implementation.
Data Source
AI summary
A shift register unit is provided to include a shift register circuit having a display input circuit and at least two driving output circuits for sequentially outputting display driving pulses; each driving output circuit is configured to write a signal from a driving clock signal input terminal to a driving signal output terminal under a control of an active-level signal at a pull-up node; the shift register circuit further includes a first and/or a second pull-up voltage-stabilizing circuit; the first pull-up voltage-stabilizing circuit is connected to the pull-up node and at least configured to maintain a voltage at the pull-up node unchanged during a first driving output circuit outputs the display driving pulse; and the second pull-up voltage-stabilizing circuit is connected to the pull-up node and at least configured to maintain the voltage at the pull-up node unchanged during a last driving output circuit outputs the display driving pulse.