Gate Driving Unit Bidirectional Scanning Controller
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Solution Overview
Problem
Existing gate driving circuits face challenges in bidirectional scanning, leading to abnormal operations due to threshold voltage shifts in transistors during prolonged scanning directions, which affects the reliability and longevity of the shift register.
Innovation Solution
A gate driving unit with a forward-backward scanning controller that includes transistors configured to manage clock signals for both forward and backward scanning, preventing constant voltage states in transistor sources and reducing threshold voltage drift by alternating clock signal potentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate driving circuit performs prolonged scanning in one direction, then the scanning function is achieved, but threshold voltage shifts in transistors occur causing abnormal operations
Solution Approach 1:
The patent implements bidirectional scanning by periodically alternating between forward and backward scanning directions. The scanning controller switches the scanning direction after a predetermined number of scanning operations, preventing prolonged unidirectional scanning that causes threshold voltage shifts. This periodic reversal maintains transistor health and ensures stable operation throughout the display's lifespan.
Solution Approach 2:
The patent introduces backward scanning as the inverse of forward scanning. When threshold voltage shifts begin to affect operation stability in the forward scanning direction, the system inverts the scanning direction to backward scanning, which reverses the stress pattern on transistors and prevents cumulative threshold voltage drift, thereby maintaining reliability over extended operation periods.
2Reliability
If bidirectional scanning is implemented to prevent threshold voltage shifts, then reliability is improved, but device complexity increases due to additional control circuits
Solution Approach 1:
The scanning controller is designed with multi-functionality, serving both as the primary scanning control unit and as the bidirectional control mechanism. By integrating the direction switching function into the existing scanning controller rather than adding a separate control circuit, the patent achieves bidirectional scanning capability while minimizing the increase in device complexity.
Solution Approach 2:
The patent combines the forward scanning control, backward scanning control, and direction switching functions into a single integrated scanning controller. This merging of functions reduces the overall circuit complexity compared to having separate control circuits for each function, while still achieving the reliability benefits of bidirectional scanning.
Data Source
AI summary
A gate driving unit includes a shift register including a forward input sub-circuit and a backward input sub-circuit, and a forward-backward scanning controller. The forward-backward scanning controller transmits a first clock signal provided by the first clock signal terminal to the forward input sub-circuit and the backward input sub-circuit for forward scanning, and transmits a second clock signal provided by the second clock signal terminal to the forward input sub-circuit and the backward input sub-circuit for backward scanning. The forward input sub-circuit transmits a signal provided by the forward-backward scanning controller to the pull-up node under control of an enabling signal provided by the forward scanning input terminal, and the backward input sub-circuit transmits the signal provided by the forward-backward scanning controller to the pull-up node under control of an enabling signal provided by the backward scanning input terminal.