Shift Register Latch Circuit for Low-Cost Bidirectional Gate Driving
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Solution Overview
Problem
Existing gate driving circuitries for large-size Organic Light-Emitting Diode (OLED) displays face challenges in reducing manufacturing costs while effectively utilizing both N-type and P-type Thin Film Transistors, requiring a more efficient and cost-effective shift register unit design.
Innovation Solution
A shift register unit comprising an input circuitry, a first latch circuitry, and a second latch circuitry, with phase inverters and transmission gates, that outputs gate driving signals and ON signals based on clock signals, simplifying the circuit structure and enabling cascaded operation for efficient scanning operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a gate driving circuitry is used to reduce manufacture cost in large-size OLED display, then manufacturing cost is reduced, but the circuit structure becomes more complex and difficult to manufacture
Solution Approach 1:
The shift register unit is divided into multiple functional modules: input circuitry (first transmission gate), first latch circuitry (first and second phase inverters), second latch circuitry (third and fourth phase inverters), and output circuitry (fifth phase inverter). Each module performs a specific function in the signal processing chain, allowing independent optimization and simplifying the overall manufacturing process while maintaining cost-effectiveness
Solution Approach 2:
The shift register unit is designed with universal functionality that can be cascaded to form complete gate driving circuitry for large-size OLED displays. The same circuit topology can drive gates in both forward and backward directions, and multiple units can be connected in series to cover the entire display area, reducing the need for different circuit designs for different applications
2Reliability
If both N-type and P-type TFTs are applied in panel process, then device performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
Different transistor types are strategically assigned to different circuit positions based on their electrical characteristics. N-type TFTs are used where high electron mobility is required (such as in switching positions), while P-type TFTs are used where hole transport is more efficient. This localized optimization maintains high device performance while allowing the use of standard manufacturing processes for each transistor type
3Ease of manufacture
If a simple circuit structure is used for shift register unit, then manufacturing cost is reduced, but scanning efficiency in both directions may be compromised
Solution Approach 1:
The circuit incorporates dynamic control mechanisms where transmission gates can be selectively enabled or disabled based on the desired scanning direction. The phase inverters are configured to dynamically adjust signal phases to accommodate bidirectional scanning requirements, allowing the same simple circuit structure to efficiently scan in both forward and backward directions without sacrificing performance
Data Source
AI summary
The present disclosure provides a shift register unit, a gate driving circuitry and a method for driving the gate driving circuitry. The shift register unit includes an input circuitry, a first latch circuitry, a second latch circuitry and an output end. The input circuitry is configured to output an input control signal to the first latch circuitry in accordance with a first level signal, a second level signal and a first ON signal. The first latch circuitry is configured to output an output signal as a gate driving signal via the output end in accordance with a first clock signal and the input control signal, and latch the output signal. The second latch circuitry is configured to output a second ON signal in accordance with a second clock signal and the output signal, and latch the second ON signal.