Display Panel Pixel Circuit Layout for Threshold Drift Compensation
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Solution Overview
Problem
Existing display panels face issues with threshold voltage drift in drive transistors over time, affecting display uniformity due to slow changes in internal transistor characteristics.
Innovation Solution
Incorporating a pixel circuit with a data write device, drive device, bias adjustment device, reset device, and initialization device, along with bias adjustment, reset, and initialization signal lines and buses, to actively manage and compensate for threshold voltage drift by adjusting the potential difference between the gate and drain of the drive transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pixel circuit without bias adjustment is used, then the device complexity is low, but the threshold voltage drifts over time affecting display uniformity
Solution Approach 1:
The bias adjustment device performs preliminary adjustment of the drive transistor's threshold voltage before the display operation begins. By applying a bias adjustment signal during the initialization phase, the system pre-compensates for expected threshold voltage drift, ensuring display uniformity is maintained throughout the device's operational life without requiring continuous complex adjustments.
Solution Approach 2:
The invention changes the electrical parameter (threshold voltage) of the drive transistor by applying a bias adjustment signal through the bias adjustment device. This signal modifies the gate-drain potential difference, directly adjusting the threshold voltage to counteract drift effects and maintain consistent display performance over time.
2Reliability
If signal lines are routed in the same layer, then the manufacturing process is simpler, but signal interference increases affecting signal quality
Solution Approach 1:
The patent transitions from two-dimensional planar routing to three-dimensional multi-layer routing for signal lines. By placing the bias adjustment signal line in a different layer from other signal lines and using bridge connections, the invention spatially separates signals to eliminate interference while maintaining manufacturing feasibility through standard multi-layer PCB or flexible circuit techniques.
3Area of stationary object
If the bias adjustment signal line is placed farther from the display region, then the display region area is maximized, but the signal line length increases causing signal degradation
Solution Approach 1:
The bridge structure acts as an intermediary connection that allows the bias adjustment signal line to be positioned in a different layer closer to the display region. This intermediate structure reduces the effective signal path length and maintains signal integrity while still maximizing the display region area by optimizing the spatial arrangement of signal routing.
Data Source
AI summary
A display panel includes a pixel circuit and a light-emitting element. The pixel circuit includes a data write device, a drive device and a bias adjustment device. The display panel includes a bias adjustment signal line, at least one of a reset signal line or an initialization signal line. At least one side frame of the display panel includes a bias adjustment signal bus, at least one of a reset signal bus or an initialization signal bus. The bias adjustment signal bus and the reset signal bus are disposed in a same layer, in a case where the bias adjustment signal bus is father away from a display region of the display panel than the reset signal bus, the bias adjustment signal bus is electrically connected to a corresponding bias adjustment signal line through a bridge disposed in a different layer from the bias adjustment signal bus.