Double-Gate Compensation Transistor for OLED Flickering
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Solution Overview
Problem
Existing display substrates for organic light emitting diode (OLED) displays face issues with flickering due to current leakage in the compensation transistor, especially during the light emitting phase.
Innovation Solution
The display substrate incorporates a sub-pixel driving circuit with a compensation transistor that includes a double-gate transistor with an intermediate node. A voltage stabilizing transistor is connected to provide a stable reference signal to the intermediate node, preventing current leakage and flickering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional single-gate transistor is used in the compensation transistor, then the device complexity is low, but current leakage occurs during the light emitting phase causing flickering
Solution Approach 1:
The compensation transistor is divided into two sub-transistors (first sub-transistor and second sub-transistor) connected in series, forming a double-gate transistor structure. This segmentation allows the intermediate node between the sub-transistors to be stabilized independently, preventing current leakage during the light emitting phase while maintaining display stability.
Solution Approach 2:
A voltage stabilizing transistor is introduced as an intermediary component to provide a stable reference signal to the intermediate node of the double-gate transistor. This intermediary element actively stabilizes the intermediate node voltage, preventing fluctuations that would cause current leakage and flickering in OLED displays.
2Reliability
If the intermediate node of the double-gate transistor is not stabilized, then the device complexity is low, but current leakage occurs causing display flickering
Solution Approach 1:
The voltage stabilizing transistor operates as a feedback mechanism by continuously monitoring and adjusting the intermediate node voltage to maintain it at a stable reference level. This feedback control prevents current leakage in the compensation transistor during the light emitting phase, ensuring stable display performance without excessive complexity.
3Reliability
If a double-gate transistor with voltage stabilizing transistor is used, then current leakage is prevented and flickering is eliminated, but the sub-pixel area increases
Solution Approach 1:
The conductive connection portion is designed to extend in multiple directions (first direction and second direction) to connect the intermediate node to the reference signal line. This multi-dimensional routing allows efficient use of space and reduces the overall sub-pixel area required for the double-gate transistor structure while maintaining its current-stabilizing function.
Data Source
AI summary
A display substrate includes: a base substrate, a plurality of sub-pixels arranged on the base substrate, a plurality of reference signal lines and a plurality of first light emitting control lines; the sub-pixel includes a sub-pixel driving circuit, and the sub-pixel driving circuit includes: a driving transistor, a compensation transistor, a voltage stabilizing transistor and a first conductive connection portion; a first electrode of the compensation transistor is coupled to a second electrode of the driving transistor, a second electrode of the compensation transistor is coupled to a gate electrode of the driving transistor, and the compensation transistor includes a double-gate transistor, the double-gate transistor includes two sub-transistors connected in series, and active patterns of the two sub-transistors are coupled to form an intermediate node; a gate electrode of the voltage stabilizing transistor is coupled to a corresponding first light emitting control line.