Shift Register Bi-Directional Scanning Driving Circuit
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Solution Overview
Problem
Existing shift registers can only perform forward scanning driving and lack the capability for bi-directional scanning driving, which limits their application in display technologies.
Innovation Solution
A shift register design that includes multiple Thin Film Transistors (TFTs) and a storage capacitor, allowing for both forward and reverse scanning driving by utilizing specific TFT configurations and signal controls to manage pulling-up and reset operations across multiple stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional shift register unit structure is used, then the circuit is relatively simple, but it can only perform forward scanning driving and lacks bi-directional scanning capability
Solution Approach 1:
The shift register unit is designed to perform multiple functions: forward scanning driving, reverse scanning driving, and self-reset operations. By integrating these functions into a single circuit unit, the shift register achieves bi-directional scanning capability without requiring separate circuits for each function, thus improving versatility while controlling complexity.
Solution Approach 2:
The circuit employs dynamic control through clock signals (CLK1, CLK2) and scanning direction selection signals (S1, S2) that can switch the operating mode between forward and reverse scanning. The TFTs are configured to dynamically change their conduction states based on the input signals, enabling the circuit to adapt its behavior to different scanning directions.
2Adaptability or versatility
If multiple TFTs and control units are added to achieve bi-directional scanning, then scanning versatility is improved, but the number of components and circuit complexity increases
Solution Approach 1:
The circuit merges the forward scanning path and reverse scanning path into a single integrated unit. The same TFTs (T1-T10) and storage capacitor (C1) are used for both forward and reverse scanning operations, rather than having separate circuits for each direction. This merging reduces the total number of components compared to having independent forward and reverse scanning circuits.
Solution Approach 2:
The shift register unit includes self-reset functionality where the circuit automatically resets itself during operation. The reset unit (comprising TFTs T4-T10 and associated capacitors) is integrated into the main circuit and automatically performs reset operations based on clock signals, eliminating the need for external reset control circuits and reducing overall component count.
3Reliability
If a reset unit and reset control unit are integrated, then the output terminal can be reliably reset to low level, but the circuit structure becomes more complex
Solution Approach 1:
The reset unit is designed to proactively reset the output terminal to a known low state before the next scanning operation begins. The reset control logic uses clock signals to trigger reset operations in advance, ensuring that the output is always in a defined state before new data is shifted in, thereby improving reliability without requiring complex continuous monitoring circuits.
Solution Approach 2:
The reset control unit acts as an intermediary between the main shift register circuit and the output terminal. It uses intermediate storage elements (capacitors C2, C3) and control TFTs (T11-T16) to mediate the reset operation, isolating the complex reset control logic from the main data path while ensuring reliable reset functionality. This intermediary structure manages complexity by separating concerns.
Data Source
Figure 1A
Figure 1B
Figure 2A~2B
AI summary
The present disclosure provides a shift register for solving the problem that the shift register in the prior art can only perform a forward scanning driving but can not perform a bi-directional scanning driving. The shift register includes: a first TFT, a second TFT, a reset unit and a pulling-up unit. The present disclosure further provides a display including the shift register. The shift register and the display can achieve a bi-directional scanning driving.