Array Substrate Pixel Circuit Layout for Leakage-Stable Brightness
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Solution Overview
Problem
Current display panels face issues with pixel circuit leakage, leading to changes in display brightness and affecting the overall display effect due to abnormalities in the display picture.
Innovation Solution
An array substrate with multiple metal layers and initialization transistors is used, where a first initialization transistor is connected between a metal wire and the gate of a drive transistor, and a second initialization transistor is connected between a metal wire and a light-emitting element, allowing for the transmission of initialization voltages to enhance threshold compensation and reduce parasitic capacitance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a common pixel circuit structure is used, then the device complexity is low, but pixel circuit leakage occurs causing display brightness instability
Solution Approach 1:
The pixel circuit is segmented into multiple functional blocks: drive transistor, first initialization transistor, second initialization transistor, storage capacitor, and compensation capacitor. This segmentation allows independent optimization of each block to reduce leakage and improve stability without overly complicating the overall circuit.
Solution Approach 2:
Initialization transistors are introduced to pre-charge or pre-discharge capacitors before the pixel circuit operates. The first initialization transistor initializes the storage capacitor, and the second initialization transistor initializes the compensation capacitor, preventing leakage-induced brightness instability before it occurs.
2Manufacturing precision
If more metal layers are added for initialization voltage transmission, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The patent utilizes multiple metal layers stacked in the vertical dimension to transmit initialization voltages. The first metal layer transmits the first initialization voltage to the storage capacitor, while the second metal layer transmits the second initialization voltage to the compensation capacitor. This vertical stacking achieves precise voltage transmission without increasing horizontal circuit complexity.
Solution Approach 2:
The multiple metal layers serve dual functions: they provide electrical connections for initialization voltages and simultaneously act as part of the overall circuit interconnect structure. This multi-functionality reduces the need for additional dedicated structures, balancing manufacturing precision with device complexity.
3Reliability
If initialization transistors are added to reduce parasitic capacitance effects, then the display uniformity improves, but the productivity decreases
Solution Approach 1:
The first and second initialization transistors are merged into the pixel circuit structure, sharing space and functions with other circuit elements. Their gates are connected to scan lines, and they work cooperatively with the drive transistor and capacitors to achieve uniform display output while maintaining reasonable integration density.
Data Source
AI summary
An array substrate includes a substrate, an active layer, multiple metal layers and pixel circuits. A pixel circuit of the multiple pixel circuits includes a drive transistor, a first initialization transistor, and a second initialization transistor. The multiple metal layers include a first metal wire extending in a first direction and a second metal wire extending in a second direction. The first metal wire and the second metal wire are located in different layers. The first initialization transistor is connected between the first metal wire and a gate of the drive transistor and is configured to transmit a first initialization voltage on the first metal wire to the gate of the drive transistor. The second initialization transistor is connected between the second metal wire and a light-emitting element and is configured to transmit a second initialization voltage on the second metal wire to the light-emitting element.