Array Substrate Black Matrix for Parasitic Capacitance Reduction
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Solution Overview
Problem
Liquid crystal display panels, particularly FFS panels, suffer from non-uniform voltage on the common electrode, leading to greenish and flickering images due to parasitic capacitance between the common electrode and gate/data lines, which existing technologies have not adequately addressed.
Innovation Solution
An array substrate with a black matrix is formed on the substrate to increase the distance between the common electrode and gate/data lines, reducing parasitic capacitance and enhancing voltage uniformity, comprising specific layers and manufacturing steps including photolithographic processes for precise layer formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the common electrode is positioned close to gate lines and data lines for compact design, then device area is reduced, but parasitic capacitance increases causing non-uniform voltage and image defects
Solution Approach 1:
A black matrix layer is introduced as an intermediary between the common electrode and the gate/data lines. This black matrix serves as a shielding layer that reduces parasitic capacitance coupling while allowing the common electrode to maintain its compact positioning near the signal lines, thus resolving the contradiction between small device area and low parasitic capacitance
Solution Approach 2:
The solution adds a vertical dimension by stacking the black matrix layer between the common electrode and the gate/data lines in the cross-sectional structure. This dimensional arrangement creates electrical isolation in the vertical field while maintaining horizontal proximity, reducing parasitic capacitance without increasing planar device area
2Reliability
If voltage is applied to common electrode to achieve alternate current mode, then after images are eliminated, but non-uniform voltage causes greenish and flickering images
Solution Approach 1:
The black matrix layer acts as a shielding intermediary that reduces parasitic capacitance between the common electrode and signal lines. By minimizing capacitive coupling, the voltage distribution on the common electrode becomes more uniform during alternate current driving, eliminating both after-images and greenish/flickering artifacts simultaneously
3Stability of the object's composition
If black matrix is added to reduce parasitic capacitance, then voltage uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The black matrix is designed to serve multiple functions simultaneously: it provides optical shielding to define display regions, acts as an electrical shield to reduce parasitic capacitance, and serves as a structural layer in the device architecture. This multi-functionality allows voltage uniformity improvement without proportionally increasing manufacturing complexity
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 solution effectively reduces parasitic capacitance, improving image uniformity and reducing greenish and flickering phenomena in liquid crystal display panels by enhancing voltage uniformity on the common electrode, while simplifying the manufacturing method.
Implementation Method 1
a black matrix formed on the first passivation layer, and a common electrode formed on the black matrix and the first passivation layer
Data Source
AI summary
A manufacturing method of an array substrate includes: providing a first substrate; forming a gate line, a data line, and a thin-film transistor array on the first substrate; forming a pixel electrode on the thin-film transistor array; depositing and forming a first passivation layer on the pixel electrode, the data line, and the thin-film transistor array; forming a black matrix on the first passivation layer; and forming a common electrode on the black matrix and the first passivation layer. The black matrix has a size that completely covers at least the data line such that when the common electrode is formed on the black matrix and the first passivation layer, a portion of the common electrode that corresponds exactly to the data line is completely spaced from the data line by the black matrix and the first passivation layer.