Shift Register Unit Bi-Directional Scanning Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional shift register units in liquid crystal displays and OLEDs cannot perform bi-directional scanning, limiting their ability to rotate displayed images by 180°.
Innovation Solution
A shift register unit with a driving module and an output module, connected at a pull-up node, that controls signal levels based on forward and reverse selection signals and scan signals to enable bi-directional scanning by selectively outputting clock signals to gate lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional shift register unit with a pull-down circuit is used, then the circuit can maintain stable voltage output, but it cannot perform bi-directional scanning
Solution Approach 1:
The patent applies the dynamics principle by making the pull-down circuit controllable rather than fixed. The pull-down circuit is enabled or disabled based on the scan direction (forward or reverse), allowing the circuit behavior to change dynamically. This enables bi-directional scanning while maintaining stable voltage output through selective activation of the pull-down circuit during different scan phases.
Solution Approach 2:
The patent changes the operational parameters of the pull-down circuit based on scan direction. By controlling the enable signal to the pull-down circuit according to whether the scan is moving forward or backward, the circuit adapts its behavior to maintain stability during both scanning directions, thus achieving bi-directional capability without adding significant complexity.
2Reliability
If the pull-down circuit is always enabled to maintain stable output voltage, then voltage stability is achieved, but the inability to scan in reverse direction occurs
Solution Approach 1:
The pull-down circuit is designed to be dynamically controllable through an enable signal that changes based on scan direction. During forward scanning, the pull-down circuit is enabled to maintain voltage stability. During reverse scanning, the pull-down circuit is disabled to allow proper voltage levels for reverse operation. This dynamic control resolves the contradiction between maintaining voltage stability and enabling bi-directional scanning.
3Adaptability or versatility
If the circuit is designed for unidirectional scanning only, then the circuit structure remains simple, but the display device cannot rotate images by 180°
Solution Approach 1:
The shift register unit is designed with multi-functionality by incorporating a controllable pull-down circuit that can operate in different modes. The same basic circuit structure supports both forward scanning (with pull-down enabled) and reverse scanning (with pull-down disabled), making the display device capable of image rotation. This universal design achieves bi-directional capability without requiring separate circuits for each scanning direction.
Data Source
AI summary
A shift register unit, a gate driving apparatus and a display device are configured to solve the problem that a bi-directional scan function can not be realized in the prior art. The shift register unit includes: a driving module, which is configured, in a forward scan, to control a signal at a pull-up node to be at a first level when a forward selection signal is at the first level or is changed from the first level to a second level, and to control the signal at the pull-up node to be at the second level when a reverse selection signal is at the first level; and is configured, in a reverse scan, to control the signal at the pull-up node to be at the first level when the reverse selection signal is at the first level or is changed from the first level to the second level, and to control the signal at the pull-up node to be at the second level when the forward selection signal is at the first level; and an output module configured to output a received clock signal (CLK) under the control of the signal at the pull-up node.