LED Driving Transistor Reset and Compensation Circuit
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Solution Overview
Problem
The image retention phenomenon in light-emitting diode displays, particularly in AMOLEDs, occurs due to charge accumulation at the driving-transistor channel, leading to poor image quality and ghost images when transitioning from black to gray scales, as the expected brightness is not achieved efficiently, causing chromatic aberration and prolonged conversion times.
Innovation Solution
A light-emitting diode device control method that involves resetting the control terminal of the driving-transistor using a reset voltage source, compensating it to a compensation voltage level, and then setting the first terminal to a target voltage level to increase the voltage difference between the terminals, thereby stabilizing the driving current and preventing malfunction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a driving-transistor is used to provide current to drive a light-emitting diode, then the light-emitting diode can emit light, but charge accumulation occurs at the channel of the driving-transistor causing image retention phenomenon
Solution Approach 1:
The patent applies preliminary action by performing a reset operation on the driving-transistor channel before the actual display operation. The method includes: resetting the control terminal of the driving-transistor using a reset voltage source, compensating it to a compensation voltage level, and then setting the first terminal to a target voltage level to increase the voltage difference between the terminals. This preliminary reset and compensation action prevents charge accumulation before it occurs during normal operation, thereby eliminating image retention phenomenon while maintaining reliable light emission.
2Stability of the object's composition
If the voltage difference between terminals of the driving-transistor is increased, then the driving current stability is improved, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the voltage levels at the control terminal and first terminal of the driving-transistor. The method involves changing the voltage parameter from initial levels to compensation voltage level, and then to target voltage level, thereby increasing the voltage difference between terminals. This parameter adjustment stabilizes the driving current without requiring additional hardware components, thus improving current stability while avoiding increased device complexity.
Data Source
AI summary
A light-emitting diode device control method includes using a reset voltage source to reset a control terminal of a driving-transistor of the light-emitting diode device; compensating the control terminal of the driving-transistor to a compensation voltage level; resetting a first terminal of the driving transistor to a target voltage level so as to increase a voltage difference between the first terminal and a second terminal of the driving transistor; and the driving transistor providing a driving current for driving a light-emitting diode of the light-emitting diode device to emit light.