IPS Pixel Electrode Spacer Overlap Prevents Domain Formation
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Solution Overview
Problem
In liquid crystal display devices operating in IPS mode, the reduction in the number of comb-shaped electrodes per pixel leads to domain formation, causing light leakage and scattering during black displays and affecting brightness and contrast, especially when viewed from oblique angles.
Innovation Solution
A liquid crystal display device design featuring a pixel electrode with a single comb-shaped electrode and a columnar spacer, where the tip of the comb-shaped electrode is folded with decreasing width towards its end, and the columnar spacer overlaps the pixel electrode to prevent reverse rotation of liquid crystal molecules, thereby eliminating domain formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the number of comb-shaped electrodes per pixel is reduced to one, then the manufacturing complexity is reduced, but domain formation occurs causing light leakage and scattering
Solution Approach 1:
The patent applies local quality by creating a non-uniform electric field distribution through the specific comb-shaped electrode design. The electrode width varies along its length, with the width gradually decreasing from the base to the tip. This creates stronger electric field intensity near the base and weaker intensity toward the tip, preventing uniform domain formation across the pixel while maintaining single-electrobe simplicity
Solution Approach 2:
The patent employs asymmetry by designing the comb-shaped electrode with unequal arm lengths and varying width. The electrode arms are positioned asymmetrically relative to the pixel center, and the width tapers asymmetrically from base to tip. This asymmetric configuration creates an optimized electric field distribution that prevents domain formation while maintaining manufacturing simplicity
2Measurement precision
If high definition screen resolution is increased, then the image quality is improved, but the pixel area is reduced making it difficult to implement multiple comb-shaped electrodes
Solution Approach 1:
The patent applies segmentation by dividing the single comb-shaped electrode into multiple functional segments along its length. Each segment of the comb electrode (with its multiple arms) creates localized electric field regions that collectively cover the entire pixel area. This segmented approach allows high-resolution display while maintaining a single continuous electrode structure that fits within reduced pixel dimensions
Solution Approach 2:
The patent transitions from considering only the number of electrodes (one dimension) to utilizing the dimensional characteristics of the electrode itself. By varying the electrode width and arm configuration along its length, the single electrode creates multiple effective electric field zones, effectively adding a dimensional aspect to the electrode design that compensates for the reduced pixel area
3Object-affected harmful factors
If multiple comb-shaped electrodes are used per pixel, then domain formation is prevented, but the manufacturing complexity and process difficulty increase
Solution Approach 1:
The patent merges multiple electrode functions into a single comb-shaped electrode structure. Instead of fabricating and aligning multiple separate electrodes, the design combines the functionality of what would traditionally require multiple electrodes into one integrated structure with varying width and asymmetric arm configuration. This merging simplifies the fabrication process to a single electrode formation step while maintaining domain prevention capabilities
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
This configuration effectively prevents domain occurrence, enhancing image quality and maintaining high contrast even in high-definition screens by minimizing light leakage and scattering, especially when viewed from oblique angles.
Implementation Method 1
driving lateral electric field
Implementation Method 2
rotate liquid crystal molecules by an electric field generated between the pixel electrode and the common electrode
Data Source
AI summary
In an IPS mode liquid crystal display device, an interlayer insulating film is formed on a common electrode formed in a planar shape, and a pixel electrode is formed on the interlayer insulating film. The distance between the TFT substrate and the counter substrate is determined by a columnar spaces. The pixel electrode includes one comb-shaped electrode and a contact part. The tip of the comb-shaped, electrode overlaps the columnar spacer as seen in a plan view. The columnar spacer is present in, the area in which an electric field that allows the liquid crystal molecules to rotate backward occurs when a voltage is applied to the pixel electrode, so that the reverse rotation of the liquid crystal molecules does not occur, and it is possible to prevent the domain from occurring.