OLED Pixel Driving Circuit Gate-Source Voltage Adjustment for Afterimage Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light-emitting diode (OLED) display devices experience a short-term afterimage phenomenon due to the magnetic hysteresis effect of driving transistors, which affects visual experience by causing accumulated charges to be released slowly, leading to prolonged afterimage duration when switching from black-and-white to grayscale images.
Innovation Solution
A pixel driving circuit is designed with a gate-source voltage adjustment circuit that increases the modulus value of the voltage difference between the control end and the first end of the light-emitting driving circuit, utilizing components like capacitors and transistors to quickly release accumulated charges, thereby stabilizing the driving transistor and reducing afterimage duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the driving transistor operates normally, then the display device can show images, but accumulated charges on the contact surface cause afterimage phenomenon and slow response when switching images
Solution Approach 1:
The patent applies preliminary action by adjusting the gate-source voltage of the driving transistor before the image switching occurs. Specifically, during the non-emission period, the gate-source voltage is increased to accelerate the release of accumulated charges on the contact surface between the active layer and gate insulating layer, thereby preventing afterimage phenomenon before it occurs
Solution Approach 2:
The patent changes the electrical parameter (gate-source voltage) of the driving transistor dynamically. By increasing the gate-source voltage during non-emission periods and maintaining it at normal levels during emission periods, the patent accelerates charge release speed and eliminates afterimage effects without affecting normal display operation
2Loss of time
If the gate-source voltage is increased to release accumulated charges quickly, then afterimage duration is reduced, but the complexity of the driving circuit increases
Solution Approach 1:
The patent implements self-service by utilizing the light-emitting control signal that already exists in the display system. The same control signal that regulates light emission is also used to control the gate-source voltage adjustment, eliminating the need for additional dedicated control circuits and reducing overall circuit complexity
Solution Approach 2:
The patent makes the light-emitting control signal serve multiple functions: it both controls the light emission of the OLED and controls the gate-source voltage adjustment of the driving transistor. This multi-functionality approach reduces the number of separate control circuits needed and simplifies the overall system architecture
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
The solution effectively shortens the duration of afterimages when switching to non-solid display images, improving the visual experience by stabilizing the driving transistor and enhancing display quality.
Implementation Method 1
due to a magnetic hysteresis effect of a driving transistor DTFT, when the OLED display device switches to display a 48 grayscale image after displaying a black-and-white image for a period of time, an afterimage phenomenon may occur
Data Source
AI summary
A pixel driving circuit and a driving method thereof, and a display device. The pixel driving circuit includes a light-emitting driving circuit, a light-emitting component and a gate-source voltage adjustment circuit. A control end, a first end and a second end of the light-emitting driving circuit are electrically connected with a first node, a second node and the light-emitting component respectively; the gate-source voltage adjustment circuit is electrically connected with at least one of the first node and the second node, the gate-source voltage adjustment circuit is also electrically connected with an adjustment voltage terminal, and the gate-source voltage adjustment circuit is configured to adjust at least one of a voltage of the first node and a voltage of the second node, so as to increase a modulus value of a voltage difference between the control end and the first end of the light-emitting driving circuit.