Shift Register Dual-Pull-Down Module Stabilizes Output Signals
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Solution Overview
Problem
Existing shift register circuits in TFT-LCD gate driving apparatuses face issues with pull-down TFT threshold instability under DC bias and output signal floating, affecting circuit reliability, especially in high-resolution small-sized displays.
Innovation Solution
A shift register design incorporating a pull-up unit, reset unit, and dual-pull-down module with specific TFT configurations and capacitor connections to stabilize output signals and prevent floating, utilizing dual-clock inputs for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shift register circuit is used with a single pull-down unit, then the circuit structure is simple, but the pull-down TFT threshold becomes unstable under DC bias and the output signal may float
Solution Approach 1:
The single pull-down unit is segmented into a dual-pull-down module with first and second pull-down units. Each pull-down unit has its own pull-down TFT that can be independently controlled by different clock signals (CLK1 and CLK2), preventing threshold instability and output floating while maintaining reasonable circuit complexity
Solution Approach 2:
The pull-down units are made dynamic by controlling them with different clock signals (CLK1 and CLK2) instead of a static DC bias. This dynamic control prevents the threshold instability that occurs with DC bias while ensuring the output signal remains stable and does not float
2Productivity
If the manufacturing method uses COG technique to adhere gate driving IC and source driving IC onto glass panel, then the bonding process is straightforward, but for small-sized high-resolution displays the driving IC length increases which is disadvantageous to bonding
Solution Approach 1:
The gate driving function is extracted from a separate IC and integrated directly into the array substrate using GOA technology. This eliminates the need for long bonding connections between separate gate driving IC and display panel, enabling small-sized high-resolution displays while maintaining ease of manufacturing
Solution Approach 2:
The gate driving circuit and display array are merged into a single integrated structure where the shift register is formed directly on the array substrate. This integration eliminates the external bonding interface, solving the bonding difficulty for small-sized high-resolution displays
Data Source
AI summary
The present invention provides a shift register, a driving method, a gate driving apparatus and a display apparatus. Said shift register comprises a pull-up unit, a reset unit, a pull-down unit and a signal output; the pull-up unit is connected to said signal output and pulls up an output signal; the reset unit is connected to a control end of said pull-up unit and said signal output respectively and resets the potential of the control end of said pull-up unit after said output signal is at high level; the pull-down unit is connected to a control end of said pull-up unit and said signal output respectively and pulls down the potential of the control end of said pull-up unit and said output signal after said reset unit has reset the potential of the control end of said pull-up unit, so that said pull-up unit switches off.