OLED Pixel Circuit with Leak-Proof Sub-Circuit for Brightness Uniformity
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Solution Overview
Problem
Current OLED display technologies face challenges in maintaining uniform brightness and display quality due to voltage leaks and threshold voltage drift, especially in low-frequency refresh modes, which can lead to flickering and reduced battery life in portable devices.
Innovation Solution
A pixel circuit design incorporating a driving sub-circuit, write sub-circuit, compensation sub-circuit, reset sub-circuit, and light-emitting control sub-circuits, along with a gradient dimming module, that compensates threshold voltages and manages voltage leaks, ensuring consistent display and reducing power consumption by varying signal frequencies and duty ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If low-frequency refresh mode is used to reduce power consumption, then battery life is extended, but brightness uniformity deteriorates due to voltage leaks and threshold voltage drift
Solution Approach 1:
The compensation sub-circuit performs preliminary compensation of threshold voltage drift before the light-emitting element is driven, storing the compensated value in a storage capacitor. This preliminary action ensures that even during low-frequency refresh intervals, the threshold voltage compensation is already in place, preventing brightness non-uniformity while maintaining low power consumption.
Solution Approach 2:
The compensation sub-circuit implements a feedback mechanism where the threshold voltage of the driving transistor is continuously monitored and compensated. The compensation signal is fed back to correct the threshold voltage drift, ensuring stable brightness output even during extended low-frequency refresh periods, thus resolving the contradiction between power saving and brightness uniformity.
2Device complexity
If conventional pixel circuits are used without dedicated leak-proof mechanisms, then device complexity is reduced, but voltage leaks cause threshold voltage drift and display quality degradation
Solution Approach 1:
A leak-proof sub-circuit is introduced as an intermediary component between the data writing sub-circuit and the driving sub-circuit. This sub-circuit actively prevents voltage leaks by providing a controlled discharge path for leaked charges, thereby protecting against threshold voltage drift and display quality degradation without significantly increasing overall device complexity.
Solution Approach 2:
The pixel circuit incorporates self-service mechanisms where the compensation sub-circuit automatically compensates for threshold voltage drift caused by voltage leaks, and the leak-proof sub-circuit autonomously manages charge leakage. These self-service functions maintain display quality without requiring external intervention or significantly complicating the circuit structure.
Data Source
AI summary
A pixel circuit, a driving method therefor and a display apparatus are provided. The pixel circuit includes a driving sub-circuit, a write sub-circuit, a compensation sub-circuit, a reset sub-circuit, a first light-emitting control sub-circuit, a second light-emitting control sub-circuit, a leak-proof sub-circuit, a storage sub-circuit and a light-emitting element. The reset sub-circuit is configured to reset a fourth node under control of a signal of a light-emitting control signal terminal and reset a fifth node under control of a signal of a reset control signal terminal. The compensation sub-circuit is configured to compensate a threshold voltage of the driving sub-circuit to the fifth node under the control of a signal of a first scanning signal terminal. The leak-proof sub-circuit is configured to write a signal of the fifth node into a first node under control of a signal of a second scanning signal terminal.