Pixel Driving Circuit Auxiliary Transistors Neutralize Substrate Charge
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Solution Overview
Problem
OLED displays face issues with hysteresis in driving transistors due to electric charges accumulated on the base substrate during fabrication, affecting brightness control.
Innovation Solution
Incorporation of auxiliary transistors in the pixel driving circuit to neutralize electric charges from the base substrate, using voltage signals to protect the driving transistor's channel part, thereby reducing hysteresis effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auxiliary transistors are added to neutralize electric charges, then hysteresis in driving transistors is reduced, but device complexity increases
Solution Approach 1:
The pixel driving circuit is segmented by introducing auxiliary transistors (first auxiliary transistor T7 and second auxiliary transistor T8) that are separately controlled by gate lines. These auxiliary transistors are positioned between the base substrate and the driving transistor to specifically neutralize electric charges accumulated on the base substrate, thereby reducing hysteresis effects while maintaining the overall circuit structure.
Solution Approach 2:
Auxiliary transistors serve as intermediary components between the base substrate and the driving transistor. They actively neutralize electric charges accumulated on the base substrate during the light emitting phase, preventing these charges from causing hysteresis in the driving transistor's threshold voltage, thus stabilizing brightness control.
2Manufacturing precision
If more transistors are incorporated to protect against charge accumulation, then brightness control precision is improved, but manufacturing complexity increases
Solution Approach 1:
The auxiliary transistors are configured to proactively neutralize electric charges accumulated on the base substrate during the light emitting phase. By performing this charge neutralization action in advance and continuously during operation, the system prevents hysteresis from developing, thereby maintaining precise brightness control without requiring complex post-manufacturing adjustments.
3Reliability
If auxiliary transistors are used to neutralize charges during light emitting phase, then driving transistor performance is improved, but energy consumption increases
Solution Approach 1:
The auxiliary transistors operate periodically during the light emitting phase of each frame, controlled by gate lines that are activated only when needed. This periodic operation allows the auxiliary transistors to neutralize charges during critical phases while remaining inactive during other phases, thereby minimizing continuous energy consumption while maintaining driving transistor performance.
Data Source
AI summary
A pixel driving circuit is provided. The pixel driving circuit includes a driving transistor, a storage capacitor; and at least one auxiliary transistor having a gate electrode, a first electrode, and a second electrode. The gate electrode of the at least one auxiliary transistor is configured to receive a gate driving signal turning on the at least one auxiliary transistor during at least a light emitting sub-phase of a frame of image to allow a voltage signal to pass from the first electrode to the second electrode of the at least one auxiliary transistor.