Liquid Crystal Display Counter Electrode Slit and Spacer Design
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Solution Overview
Problem
Liquid crystal display devices with Multi-Domain Vertical Alignment (MVA) mode face issues with alignment defects due to variations in cell gap, leading to poor display quality, such as transmissivity variations and luminosity unevenness.
Innovation Solution
A liquid crystal display device with a multi-domain structure featuring slits in the counter electrode and columnar spacers to maintain a consistent cell gap, ensuring proper alignment of liquid crystal molecules and compensating for viewing angle, while using a seal element to hold the liquid crystal layer, and employing alignment films that do not require rubbing for alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If slits or protrusions are arranged in pixel electrode or counter electrode to achieve MVA mode, then wide viewing angle is obtained, but cell gap variation causes alignment defect of liquid crystal molecules resulting in poor display quality
Solution Approach 1:
The counter electrode is divided into multiple counter electrode portions by introducing slits that extend through the counter electrode thickness. These slits segment the counter electrode into first, second, and third counter electrode portions arranged in the row direction, which creates multiple domains for liquid crystal alignment and achieves wide viewing angle while maintaining display quality through controlled segmentation
Solution Approach 2:
A resin layer is introduced as an intermediary between the array substrate and the counter substrate, filling the gaps created by the slits in the counter electrode. This resin layer acts as a mediator to maintain uniform cell gap spacing while allowing the slit structure to function for creating multiple alignment domains, thus resolving the conflict between viewing angle and alignment quality
2Reliability
If homeotropic alignment treatment is adopted to align liquid crystal molecules in horizontal direction, then high contrast ratio is obtained, but cell gap holding variations cause alignment defects
Solution Approach 1:
The counter electrode is segmented into multiple portions by slits, creating distinct domains where liquid crystal molecules can be independently aligned. This segmentation allows each domain to maintain proper homeotropic alignment with the alignment film while the overall structure achieves wide viewing angle, preventing alignment defects caused by cell gap variations
Solution Approach 2:
The resin layer serves as a mediator that maintains uniform cell gap spacing across the entire display area, including regions with slits. This intermediary structure ensures that liquid crystal molecules experience consistent spacing and alignment conditions, preventing alignment defects while maintaining high contrast ratio through proper homeotropic alignment
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 suppresses alignment defects and variations in cell gap, achieving a wide viewing angle and high contrast ratio, resulting in improved display quality and manufacturing efficiency.
Implementation Method 1
a liquid crystal layer formed in the cell gap
Implementation Method 2
a columnar spacer arranged between the first and second slits opposing to the connecting counter electrode portion to form a cell gap between the array substrate and the counter substrate
Implementation Method 3
forming a seal element in a loop shape on either one of the array substrate and the counter substrate
Data Source
AI summary
A liquid crystal display device comprises an array substrate having first and second pixel electrodes arranged adjacent each other and a counter substrate having a counter electrode opposing to the first and second pixel electrodes. First and second slits are formed on the counter electrode opposing to the first and second pixel electrode so as to cross the first and second pixel electrode, respectively. The counter electrode is separated into a first counter electrode portion and a second counter electrode portion by the first and second slits. A connecting counter electrode portion is arranged between the first and second slits to connect the first and second counter electrode portions. A columnar spacer is arranged between the first and second slits opposing to the connecting counter electrode portion to form a cell gap between the array substrate and the counter substrate.