OLED Pixel Circuit Shielding Metal for Low-Frequency Flicker
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Solution Overview
Problem
Existing OLED display devices suffer from display flicker due to leakage in dual gate transistors connected to the gate of the driving transistor, causing changes in display brightness and obvious flickering, especially during low-frequency displays.
Innovation Solution
A display panel design that includes a pixel driving circuit with a compensation transistor and shielding metal to reduce potential changes and leakage by shielding the coupling effect of other signals on active patterns, increasing parasitic capacitance and stabilizing potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual gate transistor is used to drive the gate of the driving transistor, then the transistor can provide better control and compensation capability, but the semiconductor pattern between two gate structures is easily coupled by other signals causing high potential and electricity leakage
Solution Approach 1:
The patent introduces a shielding metal layer as an intermediary element positioned between the dual gate transistor's semiconductor patterns and other signal lines. This shielding layer acts as a mediator that blocks unwanted electromagnetic coupling while allowing the dual gate transistor to maintain its control function. The shielding metal is connected to ground potential, creating an electromagnetic barrier that prevents signal leakage to the gate of the driving transistor.
Solution Approach 2:
The patent modifies the electrical parameters of the dual gate transistor region by introducing the shielding metal layer, which changes the capacitance and electromagnetic field distribution. This parameter change reduces the coupling coefficient between adjacent signal lines and the semiconductor patterns, thereby decreasing leakage current while preserving the transistor's switching and compensation capabilities.
2Reliability
If the dual gate transistor is used for compensation, then threshold voltage compensation can be achieved, but display brightness changes within one frame and obvious flickering occur during low-frequency display
Solution Approach 1:
The shielding metal layer serves as an intermediary that isolates the compensation transistor's gate region from external electromagnetic interference. This ensures that the threshold voltage compensation function operates accurately without being disrupted by coupled signals, thereby maintaining stable display brightness and eliminating flickering during low-frequency display operations.
3Illumination intensity
If shielding metal is added to reduce leakage and stabilize potential, then display flicker is reduced, but the device structure and manufacturing process become more complex
Solution Approach 1:
The patent merges the shielding metal layer with existing ground structures or integrates it into the metal interconnect layers already present in the OLED display device. By combining the shielding function with existing structural elements, the patent reduces display flicker without significantly increasing device complexity or manufacturing difficulty.
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
The solution effectively reduces leakage to the driving transistor, minimizing display brightness changes within a frame and improving low-frequency display flicker issues.
Implementation Method 1
by disposing the shielding metal on at least one of the first active pattern arranged between the first gate and the second gate and the second active pattern arranged between the third gate and the fourth gate, so that the shielding metal can shield a coupling effect of other signals on the first active pattern and the second active pattern, and increase a parasitic capacitance of the first active pattern and the second active pattern
Implementation Method 2
the shielding metal can shield a coupling effect of other signals on the first active pattern and the second active pattern
Data Source
AI summary
A display panel is provided. The display panel includes a shielding metal disposed on at least one of a first active pattern arranged between a first gate and a second gate and a second active pattern arranged between a third gate and a fourth gate, so that the shielding metal can shield a coupling effect of other signals on the first active pattern and the second active pattern, increase a parasitic capacitance of the first active pattern and the second active pattern, reduce a potential change, and improve a problem of display flicker.