Transparent Storage Capacitor Aperture Ratio Array Substrate
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Solution Overview
Problem
Existing large-size and high-resolution display panels face challenges in increasing the aperture ratio due to the space occupied by thin film transistors (TFTs) and capacitors, which limits pixel light transmission and affects display panel resolution.
Innovation Solution
The array substrate design includes a thin film transistor and a storage capacitor with transparent electrodes, where the second electrode is formed on the same level as the active layer and spaced apart from the source/drain, allowing for simultaneous formation of the first electrode and gate using half-tone masking, and the second electrode is conductorized during source/drain formation, enabling light transmission and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional opaque electrodes are used for storage capacitor, then the capacitor can be formed with standard materials and processes, but the aperture ratio is reduced because the capacitor occupies pixel area and blocks light transmission
Solution Approach 1:
The patent changes the material parameter of the electrode from opaque (traditional ITO) to transparent (double-layer structure of ITO and Mo), enabling light transmission through the storage capacitor electrode while maintaining electrical functionality. This parameter change allows the capacitor to be positioned in the pixel area without blocking light, thereby increasing the aperture ratio.
Solution Approach 2:
The patent employs a composite material structure for the transparent electrode consisting of two layers: an ITO layer and a Mo layer. This composite structure combines the electrical conductivity of ITO with the transparency and low-cost advantages of Mo, achieving both optical and electrical requirements while simplifying the manufacturing process.
2Ease of manufacture
If multiple photomasks are used for forming electrode and gate separately, then precise patterning can be achieved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent merges the patterning of the transparent electrode and the gate into a single photomasking step. By designing the photomask pattern to simultaneously define both the electrode and gate regions, the process reduces the number of photomasks from multiple to just one, lowering manufacturing cost and complexity while maintaining adequate patterning precision through careful mask design.
3Illumination intensity
If transparent electrode materials are used, then light transmission is improved and aperture ratio increases, but material selection and process control become more challenging
Solution Approach 1:
The patent uses a composite electrode structure with ITO and Mo layers. ITO provides the necessary transparency and conductivity, while Mo adds structural stability and cost benefits. This composite approach balances optical performance with material availability and process compatibility, reducing the overall complexity compared to using exotic transparent conductive oxides alone.
Solution Approach 2:
The patent optimizes the thickness parameters of the ITO and Mo layers to achieve the desired balance between transparency and conductivity. By carefully controlling these thickness parameters, the design achieves high light transmission while maintaining sufficient electrical performance, thereby reducing material complexity through parameter optimization rather than requiring complex material compositions.
Data Source
AI summary
The present application provides an array substrate and a manufacturing method thereof. The array substrate includes a thin film transistor and a storage capacitor prepared on a substrate; the thin film transistor includes a gate, an active layer, and a source/drain; the storage capacitor includes a first electrode and a second electrode isolated therefrom by a dielectric layer; the gate is disposed above the first electrode and located at one end of the first electrode; and the second electrode corresponds to a portion of the first electrode non-corresponding to the gate.