AMOLED Display Substrate with Split Initialization Lines for Gate Leakage
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Solution Overview
Problem
The enhancement of display brightness in medium-sized or large-sized AMOLED displays by setting a negative power supply signal at a lower potential leads to increased leakage of the gate electrode of the drive transistor, adversely affecting display quality, particularly in high-gray-scale displays.
Innovation Solution
A display substrate design with independent first and second initialization signal lines providing different potential signals to the gate electrode and light-emitting element, respectively, coupled with compensation signal lines to reduce resistance and voltage drop, ensuring stable operation and uniform brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the negative power supply signal is set at a lower potential to enhance display brightness, then the display brightness is improved, but the leakage of the gate electrode of the drive transistor increases
Solution Approach 1:
The patent segments the initialization signal into two separate signal lines: a first initialization signal line connected to the gate electrode of the drive transistor, and a second initialization signal line connected to the light-emitting element. This segmentation allows each signal line to operate at different potentials independently, enabling the second signal line to use a lower potential for brightness enhancement while the first signal line maintains a higher potential to minimize gate electrode leakage.
Solution Approach 2:
The patent applies different potential levels to different parts of the initialization circuit. Specifically, the first initialization signal line operates at a first potential level optimized for gate electrode control, while the second initialization signal line operates at a second (lower) potential level optimized for light-emitting element brightness. This local differentiation of signal quality resolves the contradiction between brightness enhancement and leakage reduction.
2Illumination intensity
If the initialization signal is set at a lower potential to ensure black state brightness, then the black state brightness is improved, but the leakage of the gate electrode increases
Solution Approach 1:
The patent divides the initialization signal path into two separate segments: one for the gate electrode (first initialization signal line) and one for the light-emitting element (second initialization signal line). This allows the second signal line to be set at a lower potential to improve black state brightness while the first signal line maintains appropriate potential to prevent gate electrode leakage.
Solution Approach 2:
Different potential levels are applied locally to different components: the first initialization signal line uses a potential optimized for gate electrode control to minimize leakage, while the second initialization signal line uses a lower potential optimized for black state brightness of the light-emitting element.
3Stability of the object's composition
If compensation signal lines are added to reduce resistance and voltage drop, then the brightness uniformity is improved, but the device complexity increases
Solution Approach 1:
The patent merges the compensation function with the existing initialization signal lines by adding compensation signal lines that are coupled to the first and second initialization signal lines. These compensation lines share the same signal paths and timing, allowing brightness uniformity compensation without requiring completely separate compensation circuits for each pixel.
Solution Approach 2:
The compensation signal lines are designed to work alongside the initialization signal lines, serving dual purposes: maintaining signal integrity during initialization and compensating for voltage drops during operation. This multi-functionality reduces the need for additional dedicated compensation circuits, thereby limiting the increase in device complexity.
Data Source
AI summary
A display substrate and a display device. A sub-pixel in the display substrate comprises: a first initialization signal line and a second initialization signal line, the potentials of initialization signals transmitted by the first initialization signal line and the second initialization signal line being different; a sub-pixel driving circuit in the sub-pixel comprises a drive transistor, a first reset transistor and a second reset transistor; a first electrode of the drive transistor is coupled to a light-emitting element; a first electrode of the first reset transistor is coupled to a gate electrode of the drive transistor, and a second electrode of the first reset transistor is coupled to the first initialization signal line; a first electrode of the second reset transistor is coupled to the light-emitting element, and a second electrode of the second reset transistor is coupled to the second initialization signal line.