TFT-LCD Array Substrate Rubbing Process for White Mura Elimination
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Solution Overview
Problem
The manufacturing process of TFT-LCD array substrates often results in white Mura defects due to metal scraps and excessive cloth scraps generated during the rubbing process, which disrupt the ordered arrangement of liquid crystal molecules, leading to uncontrolled bright pixel points and adverse effects on image quality.
Innovation Solution
A method involving the formation of a transparent protection layer in the non-display area, using a patterning process to create a surface height lower than or equal to the alignment film, which prevents metal wires from being rubbed by the printing roller, thereby reducing metal and cloth scraps, and ensuring orderly liquid crystal molecule arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the printing roller rubs the alignment film surface to form regular lines, then liquid crystal molecules can be arranged consistently, but metal scraps and cloth scraps are generated on the non-display area, damaging the alignment film and causing white Mura defects
Solution Approach 1:
The patent divides the substrate surface into display area and non-display area, and further divides the non-display area into circuit bonding area and other areas. By segmenting the rubbing process to only affect the display area through precise positioning, metal scraps and cloth scraps are prevented from being generated on the non-display area, thus eliminating the source of white Mura defects while maintaining liquid crystal alignment in the display area
Solution Approach 2:
The patent introduces a protective film as an intermediary layer between the printing roller and the alignment film in the non-display area. This protective film prevents direct contact between the printing roller and the alignment film during the rubbing process, thereby preventing generation of metal scraps and cloth scraps that would otherwise damage the alignment film and cause white Mura defects
2Measurement precision
If optical detection is used to detect defects on the array substrate, then some defects can be identified, but the thin pixel electrode layer reduces defect recognizability, increasing omission of white Mura defects
Solution Approach 1:
The patent performs preliminary prevention by protecting the alignment film in the non-display area before the rubbing process occurs. By preventing the generation of metal scraps and cloth scraps at the source through the protective film and segmented rubbing approach, white Mura defects are prevented from occurring in the first place, making detection unnecessary and eliminating the limitation of optical detection on thin pixel electrode layers
Data Source
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AI summary
An array substrate, a method of manufacturing the array substrate, and a display device are disclosed, for eliminating white Mura defects generated during the Cell process. The method comprises steps of: forming a display area and a non-display area on a substrate, a circuit bonding area being arranged within the non-display area; forming an alignment film within the display area through a patterning process; forming, through a patterning process, a transparent protection layer at least in a portion of the non-display area other than the circuit bonding area; and forming, through a rubbing-imprinting process, a plurality of lines having the same orientation on a surface of the alignment film, for an ordered arrangement of liquid crystal molecules, wherein a surface height of the transparent protection layer is lower than or equal to a surface height of the alignment film.