Liquid Crystal Display Alignment Film Rubbing Angle
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Solution Overview
Problem
Liquid crystal display devices face issues with light leakage and high transmittance during black display due to abnormal alignment of liquid crystal molecules caused by interactions between rubbing directions of alignment films and transverse electric fields, leading to reduced contrast ratio and viewing angle.
Innovation Solution
The liquid crystal display device employs a specific alignment film rubbing direction that crosses the oblique electrode direction at an acute angle of 3.6° or more, ensuring uniform alignment of liquid crystal molecules and preventing light leakage, thereby maintaining low transmittance during black display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the alignment film is subjected to rubbing treatment in a conventional direction, then the liquid crystal molecules can be initially aligned, but light leakage occurs and transmittance increases during black display due to abnormal alignment caused by interaction with transverse electric fields
Solution Approach 1:
The patent changes the rubbing direction parameter from conventional directions (0° or 45° relative to the electrode extending direction) to a specific direction forming an acute angle of 3.6° or more. This parameter change in the rubbing direction eliminates the abnormal alignment caused by transverse electric fields, preventing light leakage while maintaining proper liquid crystal molecule alignment during black display.
2Manufacturing precision
If the rubbing direction is adjusted to prevent light leakage, then transmittance control during black display is improved, but the alignment process becomes more complex
Solution Approach 1:
The patent specifies a precise rubbing direction parameter (acute angle of 3.6° or more relative to the electrode extending direction) that achieves optimal transmittance control during black display. This specific parameter value provides a clear manufacturing guideline that, while precise, avoids overly complex alignment processes by establishing a definite angular relationship between the rubbing direction and electrode orientation.
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 decreases transmittance during black display, enhances contrast ratio, and maintains a wide viewing angle, resulting in improved display quality.
Implementation Method 1
alignment films which are subjected to rubbing treatment, in order to initially align liquid crystal molecules
Implementation Method 2
liquid crystal layer held between the first substrate and the second substrate
Implementation Method 3
interactions between rubbing directions of alignment films and transverse electric fields
Data Source
AI summary
According to one embodiment, a liquid crystal display device includes a first substrate including a gate line extending in a first direction, a source line including an oblique line portion extending in a third direction which crosses at an acute angle a second direction perpendicular to the first direction, a pixel electrode including an oblique electrode portion extending in the third direction, and a first alignment film covering the pixel electrode, a second substrate including a counter-electrode which is opposed to the pixel electrode, and a second alignment film covering the counter-electrode, and a liquid crystal layer held between the first substrate and the second substrate. A first rubbing direction of the first alignment film is a direction which crosses the third direction at an acute angle, and an angle formed between the first rubbing direction and the third direction is 3.6° or more.