OLED Pixel Circuit Mobility Compensation
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Solution Overview
Problem
Conventional OLED pixel circuits face challenges in simultaneously compensating for the instability of threshold voltage and mobility of driving transistors, leading to uneven display due to the difficulty in measuring mobility and performing effective compensation.
Innovation Solution
A pixel circuit with a dual-gate driving transistor, incorporating a threshold voltage compensation unit and a mobility compensation unit, allows for simultaneous threshold voltage and mobility compensation, utilizing a dual-capacitor structure to store and adjust these values, ensuring uniform display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional 2T1C driving structure is used, then the circuit structure is simple, but threshold voltage compensation and mobility compensation cannot be performed simultaneously
Solution Approach 1:
The patent combines threshold voltage compensation and mobility compensation functions into a single pixel circuit by integrating the compensation transistor into the existing 2T1C structure. This merging allows both compensation types to be performed simultaneously without requiring separate independent circuits, thus improving adaptability while controlling device complexity.
Solution Approach 2:
The compensation transistor serves multiple functions: it acts as a switch transistor for data input, a storage capacitor for threshold voltage compensation, and enables mobility compensation through its capacitance. This multi-functionality allows the circuit to perform both threshold voltage and mobility compensation simultaneously, resolving the contradiction between compensation capability and circuit complexity.
2Measurement precision
If complex circuit structure is used to measure mobility, then mobility compensation can be achieved, but the circuit complexity increases
Solution Approach 1:
The pixel circuit uses its own existing components (compensation transistor and storage capacitor) to perform mobility measurement and compensation. The storage capacitor's capacitance value is utilized to determine mobility compensation amount, eliminating the need for external mobility measurement devices or complex additional circuitry. This self-service approach achieves precise mobility compensation while maintaining simple circuit structure.
3Measurement precision
If complex control timing is used for mobility compensation, then mobility compensation can be achieved, but the control complexity increases
Solution Approach 1:
The patent performs mobility compensation in advance during the data writing phase by utilizing the storage capacitor's voltage. The compensation amount is determined based on the capacitor's capacitance value before the actual display refresh, eliminating the need for complex real-time control timing during the display phase. This preliminary action simplifies the control timing while ensuring accurate mobility compensation.
Data Source
AI summary
The present disclosure discloses a pixel circuit, a display apparatus and a dual-gate driving transistor. The pixel circuit comprises a dual-gate driving transistor having a drain electrically connected to a first power supply terminal; a threshold voltage compensation unit electrically connected to a data terminal, a first control terminal, a first gate of the dual-gate driving transistor, and a source of the dual-gate driving transistor respectively; a mobility compensation unit electrically connected to a sensing signal terminal, a second control terminal, and the source of the dual-gate driving transistor respectively; and a light emitting control unit electrically connected to the data terminal, a third control terminal, a second gate of the dual-gate driving transistor, the source of the dual-gate driving transistor, and a light emitting device respectively. The threshold voltage compensation unit and the mobility compensation unit perform threshold voltage compensation for the dual-gate driving transistor under the control of the data terminal, the first control terminal, the sensing signal terminal, and the second control terminal; and the mobility compensation unit and the light emitting control unit perform mobility compensation for the dual-gate driving transistor and control the dual-gate driving transistor to drive the light emitting device to emit light under the control of the sensing signal terminal, the second control terminal, the data terminal, and the third control terminal.