LCD Panel TFT Shift Register Shielding Common Voltage
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Solution Overview
Problem
In conventional LCD panels, the voltage applied to the upper glass substrate affects the amorphous silicon thin-film transistors (a-Si TFTs), leading to shifts in I-V characteristics, reduced lifespan, and potential power chip malfunctions due to excessive electrical current.
Innovation Solution
A conducting layer is directly covered on the shift register using a-Si TFTs, with a first transparent electrode layer placed on top of the first TFT acting as a shift register, isolating the influence of the common voltage and preventing shifts in I-V characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conducting layer is directly covered on the shift register using a-Si TFTs, then the manufacturing process is simplified and device complexity is reduced, but the voltage from the upper glass substrate affects the TFTs causing shift in I-V characteristics and threshold voltage
Solution Approach 1:
A passivation layer is introduced as an intermediary between the upper transparent electrode layer and the a-Si TFTs in the shift register. This passivation layer acts as a mediator that blocks the harmful voltage influence from the upper glass substrate while allowing the TFTs to function normally. The passivation layer is selectively formed only in regions where a-Si TFTs are present, providing targeted protection without adding unnecessary complexity to other areas.
2Illumination intensity
If the upper glass substrate voltage is applied, then the LCD panel can be illuminated and display function is achieved, but the TFTs experience threshold voltage shift and reduced lifespan
Solution Approach 1:
The passivation layer serves as a protective intermediary that allows the display to be illuminated while protecting the TFTs from voltage-induced degradation. By selectively positioning the passivation layer over a-Si TFT regions, the structure enables normal display operation through the upper electrode while blocking harmful voltage effects from reaching the sensitive TFT channels, thus extending TFT lifespan without compromising display function.
3Ease of manufacture
If no protective layer is added, then the manufacturing process remains simple and cost-effective, but power chips may malfunction due to excessive electrical current
Solution Approach 1:
The passivation layer acts as an electrical current regulator and protective intermediary between the upper electrode and the TFTs. By blocking excessive current from reaching the a-Si TFTs, it prevents power chip malfunction while maintaining manufacturing simplicity. The layer is formed using standard semiconductor fabrication techniques and is selectively applied only where needed, avoiding unnecessary process complexity while providing essential protection.
Data Source
AI summary
The present invention discloses a liquid crystal display (LCD) panel and the method for manufacturing the same. A transparent electrode layer serving as a pixel electrode is laid out and simultaneously, a transparent electrode layer is laid out on top of a thin-film transistor (TFT) acting as a shift register. The transparent electrode layer can mask the influence of the common voltage of the common voltage electrode layer on the TFT. Therefore, the shift in the I-V characteristics of the TFT can be prevented due to the common voltage of the common voltage electrode layer. In this way, not only power consumption of the TFT in operation can be reduced to increase the life span of the TFT, but also power chips can be prevented from malfunctioning due to an overabundant flow of electric current which causes display abnormality.