GOA LCD Panel Switching Circuit for PSA Voltage Uniformity
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Solution Overview
Problem
The polymer stabilized alignment (PSA) process in LCD panels with directly formed gate drivers on the TFT substrate faces difficulties in ensuring simultaneous voltage application to gate lines, leading to Mura defects and reduced product yield.
Innovation Solution
Incorporating a switching circuit on the TFT substrate to transmit a specified voltage to all gate lines during the PSA process, ensuring uniform alignment of liquid crystal molecules and preventing Mura defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If gate drivers are directly formed on the TFT substrate to reduce manufacturing cost, then device complexity and manufacturing cost are reduced, but it becomes difficult to ensure simultaneous voltage application to all gate lines during the PSA process, leading to Mura defects and reduced reliability
Solution Approach 1:
The gate driver circuit is segmented into multiple independent output terminals, each capable of independently controlling the voltage application to corresponding gate lines. This segmentation allows simultaneous voltage application to all gate lines during PSA process while maintaining the integrated GOA structure, thereby resolving the conflict between reduced device complexity and maintained alignment uniformity.
2Ease of manufacture
If conventional PSA process is applied to GOA substrates without additional switching circuits, then manufacturing process is simplified, but voltage cannot be simultaneously applied to all gate lines, causing Mura defects and reduced product yield
Solution Approach 1:
The switching circuit is preliminarily integrated into the GOA substrate during the same manufacturing process, so that the capability for simultaneous voltage application to all gate lines is built-in before the PSA process. This preliminary integration maintains manufacturing process simplicity while enabling the PSA process to be performed correctly, thereby improving product yield without significantly complicating the manufacturing process.
3Reliability
If switching circuit is added to enable simultaneous voltage application to all gate lines during PSA process, then alignment uniformity and product yield are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The switching circuit is merged with the existing GOA substrate structure, sharing common manufacturing processes and material layers. The switching elements are integrated alongside the gate driver circuitry using the same TFT technology, so that the additional complexity is minimized while achieving the function of simultaneous voltage application to all gate lines during PSA process.
Data Source
AI summary
A LCD panel includes a gate driver, an active-matrix array and a switching circuit. The gate driver is disposed on a thin film transistor substrate, and includes a shift register, wherein the shift register has plural output terminals for successively outputting plural gate driving signals. The active-matrix array is disposed on the thin film transistor substrate, and includes plural gate lines, wherein the gate lines are connected with the output terminals of the shift register. The switching circuit is disposed on the thin film transistor substrate, and includes plural switching units, wherein each of the switching units has a first terminal electrically connected with one of the output terminals of the shift register, a control terminal electrically connected with a first input pad, and a second terminal electrically connected with a second input pad.