OLED Pixel Circuit Compensation for Magnetic Hysteresis Afterimages
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Solution Overview
Problem
OLED display panels experience short-term afterimages due to the magnetic hysteresis effect of driving transistors, leading to variations in driving currents and poor display effects when switching between different grayscale levels.
Innovation Solution
A pixel circuit comprising a light-emitting control circuit, compensation circuit, and driving circuit, where the compensation circuit outputs an initial power supply signal to ensure all driving circuits start from the same bias condition, and the driving circuit drives the light-emitting element based on the potential of the first node and a second power supply signal, thereby maintaining consistent driving current amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel circuit with switching transistor and driving transistor is used, then the OLED can be driven to emit light, but short-term afterimages occur due to magnetic hysteresis effect causing driving current variations
Solution Approach 1:
The patent applies preliminary action by introducing a compensation circuit that pre-adjusts the gate voltage of the driving transistor before the OLED lighting phase. The compensation circuit stores compensation voltage in a capacitor during the compensation phase, which compensates for threshold voltage shifts and magnetic hysteresis effects before they affect the driving current, thereby preventing short-term afterimages rather than correcting them after occurrence
Solution Approach 2:
The patent implements feedback mechanisms where the compensation circuit monitors and adjusts the gate voltage based on the actual state of the driving transistor. The compensation voltage is dynamically adjusted to counteract threshold voltage shifts and magnetic hysteresis effects, creating a closed-loop control system that maintains consistent driving current and eliminates display inconsistencies
2Adaptability or versatility
If the driving transistor converts data voltage to driving current, then the OLED can be driven, but variations in driving current amplitude occur when switching between grayscale levels
Solution Approach 1:
The compensation circuit performs preliminary adjustment of the gate voltage before the OLED lighting phase. By storing compensation voltage in a capacitor during the compensation phase, the circuit pre-corrects for threshold voltage shifts and magnetic hysteresis effects that would otherwise cause driving current variations during grayscale switching, ensuring consistent current amplitude across different grayscale levels
Solution Approach 2:
The patent changes the voltage parameter by dynamically adjusting the gate voltage of the driving transistor through the compensation circuit. The compensation voltage is varied to counteract threshold voltage shifts and magnetic hysteresis effects, thereby maintaining consistent driving current amplitude across different grayscale levels and preventing display inconsistencies
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 solution prevents short-term afterimages and improves display quality by ensuring consistent driving current output across all pixels when switching between grayscale levels, resulting in better display effects.
Implementation Method 1
the light-emitting element is used to drive the light-emitting element to emit light in response to the driving signal
Implementation Method 2
OLED display panels experience short-term afterimages due to the magnetic hysteresis effect of driving transistors
Data Source
AI summary
A pixel circuit and a driving method therefor, and a display substrate and a display device are disclosed. The pixel circuit includes a compensation circuit. The compensation circuit may output an initial power supply signal to a first node, and a driving circuit may drive a light-emitting element to emit light according to a potential of the first node and a second power supply signal provided by a second power supply end. And, each driving circuit which the display panel includes may start to work from the same bias situation and drive the corresponding light-emitting element to emit light.