Pixel Circuit Layout for Lower EM Transistor Duty Ratio
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Solution Overview
Problem
EM transistors in display devices experience low reliability due to high duty ratios during continuous driving, leading to stress and reduced lifespan.
Innovation Solution
Connecting source nodes of EM elements between adjacent pixels to share a data line, reducing the duty ratio of driving the EM elements without adding additional EM lines or signals, thereby ensuring reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If EM transistors are continuously driven at 100% duty ratio to maintain luminance, then luminance stability is improved, but transistor reliability deteriorates due to stress and reduced lifespan
Solution Approach 1:
The pixel circuit is divided into multiple sub-pixels, each with its own EM transistor. By controlling individual sub-pixels rather than driving all EM transistors continuously, the duty ratio for each transistor is reduced while maintaining overall luminance stability through coordinated control of multiple segments.
Solution Approach 2:
Instead of continuous 100% duty ratio driving, the patent implements periodic control where EM transistors are activated only when needed for specific sub-pixels. This periodic action reduces cumulative stress on each transistor while maintaining luminance stability through timely activation.
2Reliability
If separate EM lines are added to reduce duty ratio of EM transistors, then transistor reliability is improved, but device complexity increases
Solution Approach 1:
The existing EM line is designed to serve multiple functions: it controls EM transistors in different sub-pixels at different times. This multi-functional use of the same physical line reduces the need for additional dedicated EM lines, thereby reducing device complexity while still achieving reduced duty ratios through time-division control.
Solution Approach 2:
The patent implements dynamic control where the EM line is selectively activated for different sub-pixels based on their specific needs. This dynamic, adaptive approach allows the system to reduce overall EM transistor duty ratios without requiring static additional wiring, maintaining circuit simplicity while improving reliability.
Data Source
Figure 1~2A
Figure 2B
Figure 3
AI summary
A pixel circuit and a display panel including the same are disclosed according to embodiments. The pixel circuit according to embodiments includes a first pixel circuit (PXL1) including a first light emission control transistor (Tem1) to which a pulse of a first light emission control signal (EM1) is applied, and a first driving transistor (DT1) for driving a first light emitting element (ELI); and a second pixel circuit (PXL2) including a second light emission control transistor (Tem2) to which a pulse of a second light emission control signal (EM2) is applied, and a second driving transistor (DT2) for driving a second light emitting element (EL2). A node (Nla) between the first light emission control transistor (Tem 1) and the first driving transistor (DT1) and a node (N1b) between the second light emission control transistor (Tem2) and the second driving transistor (DT2) are connected.