Octagonal Storage Electrode for High Aperture Ratio TFT Arrays
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Solution Overview
Problem
The existing TFT array substrates in LCDs have a low aperture ratio due to the large area required by storage electrodes, which affects the display quality by reducing the amount of light that can pass through, thereby limiting the efficiency of the liquid crystal display.
Innovation Solution
The TFT array substrate design includes a storage electrode that shares its area between two capacitors, with a hole allowing electrical coupling between the pixel electrode and the auxiliary electrode, reducing the overall area occupied by the storage electrode and increasing the aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the storage electrode occupies a large area to ensure good capacitance, then the capacitance performance is improved, but the aperture ratio of the LCD decreases
Solution Approach 1:
The storage electrode is segmented into multiple portions (first storage electrode portion, second storage electrode portion, third storage electrode portion) that are distributed across different regions. This segmentation allows the storage electrode to achieve sufficient total capacitance while reducing the concentration of area in any single location, thereby improving the aperture ratio without sacrificing capacitance performance.
Solution Approach 2:
The storage electrode extends in multiple directions (first direction along gate lines, second direction along data lines) rather than concentrating in one dimension. This multi-dimensional distribution allows the electrode to achieve sufficient capacitance through extended coverage while maintaining lower local density, thus improving the aperture ratio while preserving capacitance function.
2Reliability
If the storage electrode is designed with extended portions along gate lines and data lines, then the capacitance is improved, but the structural complexity increases
Solution Approach 1:
The storage electrode serves multiple functions simultaneously: it provides capacitance storage, extends along gate lines and data lines to distribute electrical connections, and defines pixel unit boundaries. This multi-functionality reduces the need for separate structural elements, thereby improving capacitance while limiting the increase in structural complexity.
Solution Approach 2:
The storage electrode is merged with the common line structure, where the common line serves as the base for the storage electrode. This merging allows the storage electrode to leverage the existing common line infrastructure, achieving improved capacitance through extended coverage without proportionally increasing structural complexity.
Data Source
AI summary
A thin film transistor (TFT) array substrate includes a TFT including a drain electrode having an end configured as an auxiliary electrode, a protection layer covering the thin film transistor, a storage electrode forming on the protection layer and opposite to the auxiliary electrode, a passivation layer covering the storage electrode, and a pixel electrode formed on the passivation layer. The pixel electrode is electrically coupled to the auxiliary electrode via a hole passing through the passivation layer and the protection layer. A method of manufacturing the TFT array substrate and an associated liquid crystal display are also provided.