OLED Compensation Circuit Fast Charging Reset
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Solution Overview
Problem
Existing compensation circuits for AMOLED displays face inefficiencies in resetting threshold voltages of driver TFTs due to limited time for capacitor charging, leading to incomplete voltage reset and compromised compensation effects.
Innovation Solution
A compensation circuit employing a multiplexer to sequentially output fast charging and reset initialization signals to a reset energy storage element, reducing charging time and enhancing reset efficiency by using a reset switch and additional switches to control signal pulses and voltage adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a reset energy storage element is charged through a reset initialization signal during the Reset stage, then the gate and source voltages of driver TFTs are reset to a preset voltage, but the charging time is insufficient leading to incomplete voltage reset
Solution Approach 1:
The charging process is segmented into two distinct phases: a fast charging phase using a fast charging signal to quickly charge the reset energy storage element, followed by a precise initialization phase using a reset initialization signal to adjust the voltage to the exact preset value. This segmentation allows the system to overcome the time limitation by dividing the charging task into rapid voltage buildup followed by precise voltage adjustment.
Solution Approach 2:
The patent changes the charging parameters by switching between two different signal types with different voltage levels and charging characteristics. The fast charging signal provides high current for rapid charge, while the reset initialization signal provides precise voltage control. This parameter change enables the system to achieve both speed and precision in the voltage reset process.
2Reliability
If the driver TFTs' threshold voltages are compensated during limited Reset stage time, then display uniformity is improved, but the reset energy storage element cannot be fully charged
Solution Approach 1:
The patent employs periodic action by sequentially applying different charging signals in a structured sequence: first the fast charging signal, then the reset initialization signal. This periodic application of different signal types within the Reset stage enables the system to complete both rapid charging and precise voltage setting within the limited time duration, ensuring reliable display uniformity.
3Speed
If only a reset initialization signal is used to charge the reset energy storage element, then voltage precision is maintained, but charging speed is too slow for the limited Reset stage
Solution Approach 1:
The fast charging signal performs the preliminary action of quickly charging the reset energy storage element to near the target voltage level. This preliminary charging action reduces the remaining voltage difference that needs to be precisely adjusted, allowing the subsequent reset initialization signal to quickly achieve the exact preset voltage. This preliminary action approach solves both the speed and precision requirements.
Data Source
AI summary
A compensation circuit and an Organic Light Emitting Diode (OLED) device are disclosed. The compensation circuit includes a driver switch for driving a load, a reset energy storage element coupled to a to-be-reset terminal of the driver switch; and a reset charging circuit coupled to the reset energy storage element. During when the driver switch is reset, the reset charging circuit sequentially outputs a fast charging signal and a reset initialization signal to the reset energy storage element; the fast charging signal is for fast charging the reset energy storage element. The reset initialization signal is for adjusting the voltage output from the reset energy storage element to the driver switch's to-be-reset terminal to a preset voltage. Through the above design, the reset energy storage element may be fast charged with reduced charging time during the Reset stage, enhancing the Reset efficiency.