TFT Array Substrate Electrode Design for LCD Aperture Ratio
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Solution Overview
Problem
Liquid crystal display (LCD) panels face issues with static electricity weakness and poor optical characteristics due to misalignment between substrates, especially as panel size increases, and the superpatterned VA (S-PVA) mode has a reduced aperture ratio and slow response time.
Innovation Solution
A TFT array substrate employing an S-PVA mode with a thin film transistor array comprising a substrate with specific pixel electrode portions of varying widths and intervals, allowing for improved visibility, aperture ratio, and simplified manufacturing processes, while maintaining a liquid crystal layer between substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a common electrode patterning process is added to create slits on both substrates (PVA mode), then liquid crystal molecules can be driven symmetrically to improve viewing angle, but the device becomes more vulnerable to static electricity and shows poor optical characteristics due to misalignment
Solution Approach 1:
The patent removes the common electrode patterning step from the PVA mode, extracting only the necessary slit formation on the pixel electrode substrate while leaving the common electrode intact. This eliminates the misalignment problem and static electricity vulnerability associated with patterning both substrates, while maintaining the beneficial fringe field effects for wide viewing angle.
Solution Approach 2:
The patent segments the slit formation process to apply only to the pixel electrode substrate rather than both substrates. By dividing the domain formation approach, the invention achieves asymmetric slit configuration that maintains viewing angle performance while improving reliability against static electricity and misalignment issues.
2Illumination intensity
If the S-PVA mode divides a pixel into main and sub portions with different brightness, then visibility is improved, but the aperture ratio is reduced because more than two TFTs are required
Solution Approach 1:
The patent applies local quality by creating electrode lines with different widths and intervals within the same pixel to generate different brightness levels. The first electrode lines have narrower widths and smaller intervals compared to the second electrode lines, creating distinct brightness zones without requiring additional TFTs, thus maintaining high aperture ratio while achieving improved visibility.
Solution Approach 2:
The patent changes the geometric parameters of the electrode lines (width and interval) to create different brightness regions within the pixel. By varying these physical dimensions rather than adding more active components, the invention achieves multi-brightness display with maintained aperture ratio and simplified structure requiring only two TFTs per pixel.
3Illumination intensity
If electrode lines with different widths and intervals are used in different pixel portions, then transmittance and brightness differentiation is achieved to improve visibility, but manufacturing precision requirements increase
Solution Approach 1:
The patent implements parameter changes by defining specific width and interval relationships between different electrode lines. The first electrode lines have narrower widths and smaller intervals than the second electrode lines, creating brightness differentiation. These parameter variations are designed to be achievable with standard manufacturing tolerances, balancing visibility improvement with manufacturing feasibility.
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 enhances visibility, aperture ratio, and reduces manufacturing costs by creating a difference in transmittance and brightness within the same pixel area, improving response speed and stability of the LCD panel.
Implementation Method 1
a second pixel electrode portion comprising a plurality of spaced apart second electrode lines, the second pixel electrode portion capacitively coupled with the first pixel electrode portion
Data Source
AI summary
A TFT array is disclosed that includes a substrate, a gate line, a data line; and a pixel, wherein the pixel comprises a first pixel electrode portion comprising a plurality of spaced apart first electrode lines, the first pixel electrode portion having an associated TFT coupled to the first electrode portion, a second pixel electrode portion comprising a plurality of spaced apart second electrode lines, the second pixel electrode portion capacitively coupled with the first pixel electrode portion, wherein a width of each of the first electrode lines of the first pixel electrode portion is narrower than a width of each of the second electrode lines of the second pixel electrode portion, and an interval between adjacent first electrode lines of the first pixel electrode portion is smaller than an interval between adjacent second electrode lines of the second pixel electrode portion.