Pixel-Driving Circuit Reset Sub-Circuit Afterimage Reduction
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Solution Overview
Problem
Conventional OLED displays suffer from temporary afterimage phenomena due to the hysteresis effect of the driving transistor, leading to brightness uniformity issues and residual image problems.
Innovation Solution
A pixel-driving circuit comprising a reset sub-circuit, write-compensation sub-circuit, light-emission control sub-circuit, and driving sub-circuit, where the driving transistor is initialized to an ON state during the first phase and an OFF state during the second phase of an image frame, ensuring all sub-pixels are in the same state, and the write-compensation sub-circuit compensates the driving sub-circuit to eliminate the influence of threshold voltage on light-emitting luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driving transistor is initialized to different states during different phases, then temporary afterimage issues are reduced, but the circuit complexity increases
Solution Approach 1:
The pixel-driving circuit is divided into multiple sub-circuits including reset sub-circuit, write-compensation sub-circuit, light-emission control sub-circuit, and driving sub-circuit. Each sub-circuit performs a specific function to initialize and control the driving transistor in different phases, thereby reducing temporary afterimage while maintaining manageable complexity through functional modularization.
Solution Approach 2:
The driving transistor is initialized to a predetermined state (ON or OFF) during initialization phases before the actual light-emitting phase. This preliminary action ensures that all sub-pixels start from the same state, eliminating hysteresis effects and temporary afterimage phenomena while preserving brightness uniformity.
2Manufacturing precision
If the write-compensation sub-circuit is used to compensate the driving sub-circuit, then the influence of threshold voltage on luminance is eliminated, but the device complexity increases
Solution Approach 1:
The write-compensation sub-circuit implements a feedback mechanism that monitors and compensates for threshold voltage variations in the driving transistor. By feeding back compensation signals to adjust the driving voltage, the circuit eliminates the influence of threshold voltage drift on luminance consistency while managing complexity through intelligent control.
Solution Approach 2:
The write-compensation sub-circuit dynamically adjusts electrical parameters (voltages) in the driving sub-circuit to compensate for threshold voltage variations. By changing operating parameters rather than physical structure, the circuit achieves precise luminance control without proportionally increasing physical complexity.
3Reliability
If multiple initialization phases are implemented, then the hysteresis effect is reduced, but the time consumption increases
Solution Approach 1:
The pixel-driving circuit implements periodic initialization phases (first and second initialization phases) within each frame cycle. These periodic actions reset the driving transistor to a predetermined state at regular intervals, effectively reducing hysteresis and temporary afterimage while confining time consumption to specific phases rather than continuous operation.
Data Source
AI summary
A pixel-driving circuit includes: a write-compensation sub-circuit coupled to a signal scanning terminal, a data terminal and a driving sub-circuit, and configured to, controlled with voltage from the signal scanning terminal, provide voltages of the data terminal to the driving sub-circuit for compensation; the light-emission control sub-circuit is coupled with the light-emission terminal, the first power source terminal and the driving sub-circuit and configured to provide voltages of the first power source terminal to the first terminal of the driving transistor controlled with voltage from the light-emission control terminal; the reset sub-circuit is coupled with the reset signal terminal, the initial voltage terminal, and the driving sub-circuit and to provide voltages of the initial voltage terminal to the gate of the driving transistor controlled with voltage from the reset signal terminal, causing the driving transistor to be in ON and OFF states respectively during the first and second initialization phases.