Array Substrate Shielding Film for LCD Leakage Current Control
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Solution Overview
Problem
Picture quality deterioration in liquid crystal display devices due to leakage current in the channel layer of thin film transistors caused by light reflection from the liquid crystal cell, black matrix, and color filter.
Innovation Solution
A shielding film is formed on the passivation layer of the array substrate to intercept light reflected from the liquid crystal cell and color filter, minimizing the leakage current and improving picture quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal display panel is constructed with gate lines, data lines, pixel electrodes, and thin film transistors without additional shielding structures, then the device complexity is low and manufacturing is simple, but light reflected by the liquid crystal cell, black matrix, and color filter enters the channel layer of the thin film transistor, generating leakage current and causing picture quality deterioration
Solution Approach 1:
A shielding film is introduced as an intermediary layer between the reflected light source (liquid crystal cell, black matrix, color filter) and the channel layer of the thin film transistor. This shielding film, positioned on the passivation layer, intercepts reflected light before it can reach the channel layer, thereby preventing leakage current generation and improving picture quality without fundamentally redesigning the entire display structure
Solution Approach 2:
The shielding film is segmented to correspond specifically to the gate electrode regions, rather than covering the entire substrate. This selective placement targets the critical areas where leakage current occurs (above the channel layer) while minimizing additional structural complexity and material usage. The shielding pattern is divided into multiple regions aligned with individual gate electrodes or gate line segments
2Reliability
If a shielding film is added on the passivation layer to intercept reflected light, then leakage current is reduced and picture quality is improved, but the device complexity and manufacturing process become more complex
Solution Approach 1:
The shielding film formation process is merged with the existing passivation layer formation process. Both the passivation layer and shielding film are deposited in sequence during the same manufacturing cycle, utilizing the same deposition equipment and process conditions. This integration eliminates the need for separate shielding film deposition steps, reducing manufacturing complexity while achieving the desired light interception function
Solution Approach 2:
The shielding film serves multiple functions simultaneously: it acts as a light shield to prevent reflected light from reaching the channel layer, provides additional passivation protection, and can serve as an etch stop layer for subsequent processing steps. This multi-functionality reduces the need for separate dedicated shielding structures and simplifies the overall manufacturing process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The shielding film effectively reduces the leakage current by preventing light from entering the channel layer, thereby enhancing picture quality by maintaining accurate pixel voltage and reducing unwanted patterns.
Implementation Method 1
light reflected by the liquid crystal cell, the black matrix and the color filter
Implementation Method 2
shielding film... to intercept the light reflected by the liquid crystal cell, a black matrix and a color filter
Data Source
AI summary
An array substrate for a liquid crystal display device and a fabrication method thereof, and a liquid crystal display device having the same are disclosed. The array substrate for a liquid crystal display device and a fabrication method thereof, and a liquid crystal display device having the same according to the present disclosure eliminate optical loss by use of a shielding film that can decrease the optic leakage current to minimize the optic leakage loss, thus it is possible to improve the picture quality.