Display Sub-Pixel Circuit With Series Transistors for Leakage Control
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Solution Overview
Problem
Existing display devices face challenges in achieving improved luminance and reduced power consumption, particularly in low frequency driving methods or variable refresh rate (VRR) driving, due to leakage current characteristics.
Innovation Solution
The display device incorporates a sub-pixel design with dual transistors connected in series, where a connection node between the transistors is linked to a lower line, stabilizing the voltage at the node, thereby reducing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dual transistors are connected in series to prevent leakage current, then power consumption decreases, but device complexity increases
Solution Approach 1:
The switching transistor is divided into two sub-transistors connected in series, with the connection node connected to the lower line. This segmentation allows each sub-transistor to contribute to leakage current prevention while the lower line connection stabilizes the intermediate node voltage, achieving better power consumption reduction without excessive complexity increase.
2Loss of energy
If low frequency driving method is used to decrease power consumption, then energy efficiency improves, but leakage current characteristics worsen
Solution Approach 1:
The connection node between the two sub-transistors is connected to the lower line, which maintains a stable potential (typically ground or reference voltage). This equipotential connection prevents voltage fluctuations at the intermediate node during low frequency or VRR driving, thereby improving leakage current characteristics while maintaining energy efficiency.
3Use of energy by moving object
If variable refresh rate driving is implemented to improve energy efficiency, then power consumption decreases, but voltage stability at connection nodes deteriorates
Solution Approach 1:
The lower line serves as an intermediary element that stabilizes the voltage at the connection node between the two sub-transistors. During variable refresh rate driving, this intermediary connection prevents voltage fluctuations that would otherwise occur at the intermediate node, thereby maintaining voltage stability while allowing energy efficient operation.
Data Source
AI summary
A display device includes: a sub-pixel connected to a k-th scan line and a j-th data line crossing the k-th scan line, wherein the sub-pixel includes: a light emitting element; a driving transistor configured to provide a driving current to the light emitting element according to a data voltage applied to a gate electrode thereof and including a first lower line; a first sub-transistor and a second sub-transistor connected to the gate electrode of the driving transistor and connected to each other in series; and a first node connecting the first sub-transistor and the second sub-transistor to each other, and the first node is connected to the first lower line.