Pixel Circuit Reset Timing for Low-Frequency Flicker Control
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Solution Overview
Problem
In low-frequency working modes, the threshold voltage shift of driving transistors in pixel circuits leads to luminance inconsistency and severe flickers due to hysteresis characteristics, causing regular changes in brightness.
Innovation Solution
A pixel circuit design incorporating a driving transistor, a write-in transistor, and additional transistors that switch their on/off states before and after each duty cycle to reset the voltage levels of the driving transistor's electrodes, maintaining stability across high and low frequency modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the data signal is written continuously into the driving transistor in low-frequency working mode, then the luminance can be maintained, but the threshold voltage shifts due to hysteresis characteristics causing luminance inconsistency and flickering
Solution Approach 1:
The first transistor performs a preliminary reset action on the source or drain electrode of the driving transistor before each duty cycle begins. By resetting the voltage level in advance, the circuit prevents threshold voltage shift caused by hysteresis effects, ensuring stable luminance output from the start of each duty cycle without allowing inconsistency to develop
Solution Approach 2:
The first transistor switches its on/off state periodically before and after each duty cycle of the write-in transistor. This periodic switching creates regular reset intervals that counteract the cumulative hysteresis effects during continuous data writing, maintaining consistent threshold voltage and preventing luminance flickering throughout the frame period
2Illumination intensity
If additional transistors are added to reset voltage levels and prevent threshold voltage shift, then luminance consistency improves, but the pixel circuit structure becomes more complex
Solution Approach 1:
The first transistor is designed to perform multiple functions: it resets the voltage level of the driving transistor's source or drain electrode, prevents threshold voltage shift, and contributes to overall circuit stability. By making this single transistor multi-functional, the design achieves luminance consistency without proportionally increasing circuit complexity
Solution Approach 2:
The patent integrates the voltage reset function into the existing pixel circuit architecture by adding only one transistor (the first transistor) that works in coordination with the existing write-in transistor and driving transistor. This merging approach combines the reset function with the data writing operation, achieving threshold voltage stabilization without creating a completely separate complex subsystem
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design stabilizes the voltage levels of the driving transistor's electrodes, reducing threshold voltage shift and flickers, while also simplifying the pixel circuit structure and improving pixel density by utilizing transistors for multiple functions.
Implementation Method 1
Affected by the hysteresis characteristics, and the threshold voltage (Vth) of the driving transistor will shift
Data Source
AI summary
A pixel circuit and a display panel are disclosed. The pixel circuit includes a driving transistor, a write-in transistor, and first and second transistors. The driving transistor has a source, a drain, and a gate. The write-in transistor has a source connected to one of source and drain of the driving transistor, a drain connected to a data line, and a gate connected to a first wire. The first transistor has a source connected to a second wire, a drain connected to one of source and drain of the driving transistor, and a gate connected to a third wire. The second transistor has a source connected to the drain of the driving transistor, a drain connected to the gate of the driving transistor, and a gate connected to a fourth wire. The first transistor switches on/off state once before and after each duty cycle of the write-in transistor.