Gate Driver Dual-Stage Node Redundancy for OLED Yield
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Solution Overview
Problem
In OLED displays, the connection structure between stages in a gate driver can lead to abnormal outputs due to transistor deterioration, causing signal distortion and reducing the yield of display devices, especially in a double bank structure where both side stages share scan signals, making the gate driver unusable if any stage is defective.
Innovation Solution
A gate driver is designed with a first side stage and a second side stage, each with output units connected to nodes QL and QR, allowing both nodes to control the output units, ensuring that scan signals of the same phase are maintained even if one node operates abnormally, thus preventing abnormal outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both side stages share scan signals in a double bank structure, then signal distortion is reduced, but reliability deteriorates because abnormal output in one stage propagates to other stages
Solution Approach 1:
The gate driver is divided into independent first and second gate drivers, each controlling separate gate lines. This segmentation prevents abnormal output from propagating across the entire system, as each segment operates independently with its own signal path.
Solution Approach 2:
The patent introduces a signal routing mechanism that acts as an intermediary, allowing the first gate driver to supply scan signals to both first and second gate lines, and the second gate driver to supply scan signals to both second and third gate lines. This intermediary routing prevents direct coupling between stages that would propagate abnormalities.
2Device complexity
If stages are connected in a shared configuration, then device complexity is reduced, but abnormal outputs spread more easily between stages
Solution Approach 1:
The connection structure is segmented into distinct first and second gate drivers with separate output paths. The first gate driver connects to first and second gate lines, while the second gate driver connects to second and third gate lines, creating isolated connection segments that prevent abnormal output propagation.
Solution Approach 2:
Each gate driver is designed with multi-functionality to supply scan signals to multiple gate lines. The first gate driver can supply signals to both first and second gate lines, and the second gate driver can supply signals to both second and third gate lines, reducing overall system complexity while maintaining isolation.
Data Source
AI summary
A gate driver and a display device including the same are disclosed. The gate driver includes a first side stage including a node QL and a first output unit and outputting a first scan signal of a first phase, and a second side stage including a node QR and a second output unit and outputting a second scan signal of the first phase. The first output unit is connected to the node QL and the node QR, and the second output unit is connected to the node QL and the node QR.