TFT Substrate with Auxiliary Electrode for Wide Viewing Angle
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Solution Overview
Problem
Current liquid crystal display (LCD) technologies face limitations in side visibility and require complex manufacturing processes, which hinder the development of improved wide viewing angle capabilities.
Innovation Solution
A thin film transistor (TFT) substrate design incorporating multiple transistors, sub-pixel electrodes, and auxiliary electrodes, along with a simplified manufacturing method using multiple mask processes to form specific patterns and layers, enhances side visibility and reduces manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If vertical alignment mode is used to achieve wide viewing angle, then side visibility is improved, but manufacturing complexity increases due to additional slits or protrusions on electrodes
Solution Approach 1:
The pixel electrode is divided into multiple sub-pixel electrodes (first sub-pixel electrode, second sub-pixel electrode, third sub-pixel electrode) with different voltage levels. This segmentation allows differential voltage charging to create side visibility enhancement without requiring complex slit or protrusion structures on the electrodes, thus improving side visibility while maintaining manufacturing simplicity.
Solution Approach 2:
Different regions of the pixel are assigned different voltage levels through the sub-pixel electrodes. The first sub-pixel electrode receives a first voltage, the second sub-pixel electrode receives a second voltage, and the third sub-pixel electrode receives a third voltage. This local quality variation creates asymmetric electric field distribution that enhances side visibility without adding structural complexity to the electrode design.
2Ease of manufacture
If pixel electrode is divided into multiple sub-pixel electrodes with different voltages to improve side visibility, then image quality is enhanced, but manufacturing steps increase
Solution Approach 1:
The auxiliary electrode serves multiple functions: it is connected to the third sub-pixel electrode to provide a third voltage, and simultaneously overlaps with the common electrode to form a storage capacitor. This multi-functionality reduces the total number of manufacturing steps by combining electrode formation with capacitor structure creation, while maintaining precise voltage control through the dual-purpose design.
Solution Approach 2:
The auxiliary electrode is merged with the storage capacitor structure by having it overlap with the common electrode with insulating layers therebetween. This merging combines the voltage provision function and the capacitor function into a single structural element, reducing manufacturing complexity while maintaining the precision needed for differential voltage charging of the sub-pixel electrodes.
3Device complexity
If auxiliary electrode is added to provide differential voltage to sub-pixel regions, then side visibility is improved, but device structure becomes more complex
Solution Approach 1:
The auxiliary electrode is designed to perform multiple functions simultaneously: it provides the third voltage to the third sub-pixel electrode for differential voltage charging to enhance side visibility, and at the same time forms a storage capacitor by overlapping with the common electrode. This multi-functionality justifies the addition of the auxiliary electrode by eliminating the need for separate capacitor structures, thereby maintaining manufacturing process simplicity despite increased device functionality.
Data Source
AI summary
In a thin film transistor, first and second thin film transistors are connected to an Nth gate line and an Mth data line, and first and second sub pixel electrodes are connected to the first and second thin film transistors, respectively. A third thin film transistor includes a gate electrode connected to an (N+1)th gate line, a semiconductor layer overlapping with the gate electrode, a source electrode connected to the second sub pixel electrode and partially overlapping with the gate electrode, and a drain electrode facing the source electrode. A first auxiliary electrode is connected to the drain electrode and arranged on the same layer as the first and second sub pixel electrodes. An opposite electrode is arranged on the same layer as the gate line and at least partially overlaps with the first auxiliary electrode with at least one insulating layer disposed therebetween.