Bidirectional Shift Register Scan Pulse Sequencing for LCD Gate Lines
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Solution Overview
Problem
Conventional shift registers in liquid crystal display devices are limited to outputting scan pulses in a single direction, which restricts their application in various liquid crystal display models and hinders flexible control over the scanning process.
Innovation Solution
A shift register design that includes multiple stages with set nodes, pull-up and pull-down switching devices, and node controllers to control the logic states of nodes, allowing for the output order of scan pulses to be changed based on forward and reverse voltages, enabling bidirectional scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional shift register outputs scan pulses in only one direction, then the structure is simple, but the adaptability to various liquid crystal display models is limited
Solution Approach 1:
The shift register employs dynamic control through node controllers that can switch between forward and reverse voltage modes, enabling the output direction to change adaptively. This dynamic capability allows the same device to serve multiple display models without physical reconfiguration, resolving the contradiction between versatility and structural simplicity
Solution Approach 2:
The invention changes the operational parameters by introducing forward voltage and reverse voltage with opposite phases. By switching between these voltage states, the shift register can reverse its output direction, achieving adaptability to different display models while maintaining the same physical structure
2Ease of operation
If a shift register uses multiple node controllers to control logic states of nodes, then the scanning process control is flexible, but the device complexity increases
Solution Approach 1:
Each node controller is designed to perform multiple functions: it controls the logic state of its local node, responds to forward/reverse voltage signals, and coordinates with adjacent stages. This multi-functionality reduces the need for separate dedicated control elements, achieving flexible scanning control without proportionally increasing device complexity
Solution Approach 2:
The invention merges the control functions into integrated node controllers that handle both set and reset operations, and respond to both forward and reverse voltage inputs. By combining these functions into unified control units, the system achieves flexible scanning control while minimizing the overall number of control components
Data Source
AI summary
A shift register includes a plurality of stages for sequentially outputting scan pulses to drive a plurality of gate lines, wherein each of the stages includes a set node, a pull-up switching device for outputting a corresponding scan pulse according to a logic state of the set node, at least two reset nodes, at least two pull-down switching devices, each of the pull-down switching devices being connected to a corresponding reset node to output an off voltage according to a voltage level of the corresponding reset node, and a node controller for controlling logic states of the nodes of a corresponding stage and logic states of the nodes of stages different from the corresponding stage together, wherein the node controllers of the stages control an output order of the scan pulses from the stages according to a forward voltage and reverse voltage having opposite phases.