Pixel Circuit Transistor Type Differentiation for Power Reduction
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Solution Overview
Problem
Existing pixel circuits using Low Temperature Poly-Silicon (LTPS) technology face challenges in reducing leakage current and ensuring stable potential at the control terminal of the driving circuit, leading to high driving power consumption and inefficiency.
Innovation Solution
The proposed pixel circuit incorporates a driving circuit, data writing circuit, on-off control circuit, initialization circuits, and energy storage circuit, utilizing different types of transistors such as oxide transistors and LTPS transistors to manage threshold voltage compensation and power supply, reducing driving power by employing a compensation phase and writing phase to stabilize node potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If LTPS technology is used in the pixel circuit, then the driving power is high, but the leakage current of the transistor cannot be reduced while compensating for the threshold voltage
Solution Approach 1:
The patent applies different transistor types in different circuit regions: LTPS transistors are used where high driving power is needed (driving transistor T3, control transistor T4), while oxide transistors are used where low leakage current is critical (switching transistor T1, storage transistor T2). This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
2Reliability
If the transistor leakage current is reduced, then the potential stability is improved, but the driving power decreases
Solution Approach 1:
The patent strategically places oxide transistors with low leakage current in the switching and storage circuits (T1, T2) to ensure potential stability, while using LTPS transistors with high drive capability in the driving and control circuits (T3, T4) to maintain driving power. This spatial differentiation of transistor types resolves the contradiction between leakage reduction and power maintenance.
3Reliability
If a compensation phase is introduced, then the threshold voltage compensation is improved, but the circuit complexity increases
Solution Approach 1:
The patent implements threshold voltage compensation in advance during a compensation phase before the light emission phase. The switching transistor T1 and storage transistor T2 are used to store compensation voltages that counteract threshold voltage effects. This preliminary compensation action ensures accurate driving without requiring complex real-time adjustment circuits.
Data Source
AI summary
A pixel circuit, is provided, including: a light-emitting element, a driving circuit, a data writing circuit, an on-off control circuit, a first initialization circuit and an energy storage circuit; the data writing circuit writes a data voltage into a third node under control of a first gate driving signal; the on-off control circuit controls communication between a first node and the third node under the control of the first gate driving signal; the first initialization circuit controls writing an initialization voltage into the first node under the control of the first gate driving signal; and a type of a transistor included in the first initialization circuit is different from a type of a driving transistor included in the driving circuit, and a type of a transistor included in the data writing circuit is different from the type of the driving transistor of the driving circuit.