Pixel Driving Circuit Dual Initialization Units for Flicker Reduction
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Solution Overview
Problem
Wearable devices using low-frequency display modes experience flicker phenomena due to the leakage current of storage capacitors, leading to uneven brightness and poor display effects.
Innovation Solution
A pixel driving circuit with two initialization units, one for low-frequency and one for high-frequency modes, where the initialization units have opposite polarities to compensate for the potential of the gate electrode, reducing the flicker effect by balancing the leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single initialization unit is used in low-frequency display mode, then the circuit structure is simple, but the leakage current causes gate potential to decrease and brightness to increase gradually, resulting in flicker
Solution Approach 1:
The single initialization unit is divided into two separate initialization units: a first initialization unit connected to a first power signal terminal and a second initialization unit connected to a second power signal terminal. This segmentation allows each unit to independently compensate for leakage current, preventing the gradual potential decrease that causes flicker in low-frequency display modes.
Solution Approach 2:
The patent changes the electrical parameters by introducing two different power signal terminals with different voltage levels. The first initialization unit maintains gate potential using the first power signal, while the second initialization unit uses the second power signal to compensate for leakage, thereby stabilizing the display against flicker.
2Use of energy by moving object
If the storage capacitor maintains gate potential in low-frequency mode, then power consumption is reduced, but the leakage current causes uneven brightness across frames
Solution Approach 1:
The initialization units perform preliminary action by compensating for the leakage current of the storage capacitor before the display refresh cycle completes. This preliminary compensation maintains the gate potential within the required range, ensuring uniform brightness across frames while preserving the low-power benefit of capacitor-based potential maintenance.
3Reliability
If initialization units with opposite polarities are used, then the gate potential is maintained and flicker is reduced, but the device complexity increases
Solution Approach 1:
Both initialization units are designed with the same basic structure and function, connected symmetrically to the gate electrode. This universal design allows the circuit to handle both positive and negative leakage currents using identical unit configurations, reducing design complexity despite the increased number of components.
Data Source
AI summary
A pixel driving circuit includes a first power signal terminal and a second power signal terminal; a driving transistor including a gate electrode connected to a first node, a first end connected to a second node, and a second end connected to a third node; a light-emitting component, connected in series between a fourth node and the second power signal terminal; a first initialization unit including a first end connected to the first node, a second end connected to a first initialization signal terminal, and a control terminal connected to a first control signal terminal; and a second initialization unit including a first end connected to the first node, a second end connected to a second initialization signal terminal, and a control terminal connected to a second control signal terminal. In a same timeframe, polarities of the voltage signals at the first and second initialization signal terminals are opposite.