Array Substrate Passivation Step Height for LCD Brightness
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Solution Overview
Problem
Liquid crystal display devices face issues due to column spacer movements, which cause alignment layer damage and defects, leading to light leakage and reduced aperture ratio and brightness.
Innovation Solution
The implementation of an array substrate design with a specific structure, including common lines with a step height on the passivation layer, supports column spacers and prevents alignment layer damage by maintaining the alignment of liquid crystal molecules, thereby preventing light leakage and enhancing brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If column spacers are formed on the color filter substrate, then the cell gap is maintained uniformly, but the column spacers move under external force causing alignment layer damage and light leakage
Solution Approach 1:
The patent applies preliminary action by forming protrusions on the array substrate before assembling the liquid crystal display device. These protrusions are positioned to correspond with the column spacers, providing pre-positioned support structures that prevent spacer movement and alignment layer damage before external forces are applied during operation.
Solution Approach 2:
The protrusions act as intermediary structures between the array substrate and the column spacers. They provide a mechanical interface that supports the column spacers, distributing forces and preventing direct contact between moving spacers and the alignment layer, thus mediating the interaction to prevent damage.
2Illumination intensity
If the aperture ratio is increased to improve brightness, then more light can pass through, but column spacer movement causes light leakage that reduces display quality
Solution Approach 1:
The protrusions are formed in advance on the array substrate to provide preventive support for column spacers. This preliminary structural arrangement ensures that spacers remain stationary during device operation, preventing light leakage while allowing the aperture ratio to be optimized for brightness.
Solution Approach 2:
The patent converts the potential harm of column spacer movement (which causes light leakage) into a benefit by using the protrusions to guide and stabilize the spacers. The structures that could potentially cause damage are instead utilized as positioning features that ensure proper alignment and prevent light leakage.
3Manufacturing precision
If column spacers are used instead of ball spacers, then the cell gap can be controlled more precisely, but the column spacers are prone to movement and cause defects
Solution Approach 1:
The protrusions are formed beforehand on the array substrate to provide predetermined positioning features. This preliminary action ensures that when column spacers are assembled, they are correctly positioned and supported, maintaining both the precision advantages of column spacers and improving their stability.
Solution Approach 2:
The patent applies local quality by providing support structures (protrusions) only at specific locations where column spacers are positioned, rather than uniformly across the entire substrate. This localized approach maintains the precision benefits of column spacers while providing targeted stability where needed.
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 design effectively prevents light leakage and maintains the aperture ratio by supporting column spacers and ensuring proper alignment of liquid crystal molecules, even under external forces, thus improving the overall performance of liquid crystal display devices.
Implementation Method 1
the passivation layer has a step height at a top surface of the passivation layer due to the plurality of common lines... supports column spacers and prevents alignment layer damage
Implementation Method 2
maintaining the alignment of liquid crystal molecules... ensuring proper alignment of liquid crystal molecules
Data Source
AI summary
An array substrate includes a substrate; gate lines over the substrate along a first direction; data lines over the substrate along a second direction and crossing the gate lines to define pixel regions; a thin film transistor at each crossing portion of the gate and data lines; an insulating layer covering the thin film transistor and having a flat top surface; a common electrode on the insulating layer all over the substrate; a common line on the common electrode; a passivation layer on the common line; and a pixel electrode on the passivation layer in each pixel region and connected to the thin film transistor, the pixel electrode including electrode patterns, wherein the passivation layer has a step height at a top surface of the passivation layer due to the plurality of common lines.