Dual-Gate Transistor Pixel Circuit for OLED Threshold Voltage Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic Light Emitting Display (OLED) panels face issues with display unevenness and afterimages due to the drift of threshold voltage in driving transistors, which existing compensation methods, such as internal and external compensation, fail to adequately address, often worsening the problem.
Innovation Solution
A pixel circuit with a dual-gate transistor and an external compensation component that collects and adjusts the threshold voltage, using a processor and comparators to provide a compensation voltage, ensuring the current emitted by the light-emitting diode is independent of the threshold voltage, thereby stabilizing the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an external compensation circuit adds the increasing threshold voltage to the data signal, then the threshold voltage compensation is attempted, but the positive bias becomes larger causing more serious positive drift of the threshold voltage
Solution Approach 1:
Instead of adding the threshold voltage variation to the data signal (conventional approach), the patent subtracts the threshold voltage from the data signal to generate the compensation signal. This inverted approach ensures that when threshold voltage drifts positively, the compensation signal reduces the data signal accordingly, preventing further positive drift rather than exacerbating it.
Solution Approach 2:
The patent implements a feedback mechanism where the threshold voltage is detected and used to generate a compensation signal that is fed back to adjust the data signal. The detection unit measures the threshold voltage, and the compensation signal generation unit uses this measurement to create a corrective signal that compensates for the threshold voltage drift, forming a closed-loop control system.
2Reliability
If internal compensation is used in the pixel circuit, then the threshold voltage compensation is attempted, but it is difficult to adjust the threshold voltage to a standard threshold voltage
Solution Approach 1:
The patent introduces a dedicated compensation signal generation unit as an intermediary between the detection unit and the pixel circuit. This intermediary unit processes the detected threshold voltage and generates an appropriate compensation signal, enabling more precise control over the threshold voltage adjustment compared to direct internal compensation methods.
Solution Approach 2:
The patent divides the compensation function into separate modular units: a detection unit for measuring threshold voltage, a compensation signal generation unit for creating the correction signal, and application units for implementing the compensation. This segmentation allows each unit to be optimized independently and facilitates more precise threshold voltage adjustment.
3Device complexity
If conventional pixel circuits are used, then the structure is simple, but display unevenness and afterimages occur due to threshold voltage drift
Solution Approach 1:
The patent merges the threshold voltage detection function, compensation signal generation function, and pixel circuit operation into an integrated system. The compensation signal generation unit is combined with the pixel circuit structure, allowing threshold voltage compensation to be performed within the pixel circuit framework itself, thereby improving display quality without requiring entirely separate compensation circuits.
Data Source
AI summary
The present disclosure discloses a display panel and a display device. The display panel includes a plurality of pixel circuits, and each of the pixel circuit includes an initialization component, a data writing component, a light emitting control component, a voltage storage component, a driving transistor, a first voltage maintenance component, a switching control component, an external compensation component and a light-emitting diode. The driving transistor is a dual-gate transistor, and a second gate of the dual-gate transistor is electrically connected to the external compensation component through the switching control component. The external compensation component is under the control of the switching control component to firstly collect the voltage at a third node and then provide a compensation voltage to a second node to adjust the threshold voltage of the dual-gate transistor so that the threshold voltage of the dual-gate transistor is more approximate to a standard threshold voltage.