Liquid Crystal Display With Differently Pretilted Alignment Layers
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Solution Overview
Problem
Conventional liquid crystal displays in OCS mode face limitations in gray-scale expression due to slow switching times from a bended state to a splay state, requiring an initial electric field and taking excessively long to change the arrangement of liquid crystal molecules.
Innovation Solution
A liquid crystal display with differently pretilted alignment layers on the substrates, where the first alignment layer has a first pretilt angle and alignment angle, and the second alignment layer has a second pretilt angle and alignment angle, differing by specific degrees, to facilitate faster switching without an initial electric field, utilizing a rubbing or optical alignment process to form these layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If liquid crystal molecules are arranged in OCS mode with initial electric field applied to maintain first splay state, then gray-scale expression is restricted, but response speed improvement is limited
Solution Approach 1:
The alignment layers are pre-configured with different pretilt angles (first alignment layer: 80-85 degrees, second alignment layer: 85-90 degrees) to create an inherent tendency for liquid crystal molecules to transition from bended state to splay state without requiring initial electric field application. This preliminary structural configuration enables faster response speed while maintaining gray-scale expression capability.
Solution Approach 2:
The patent applies different pretilt angles at different locations (first alignment layer vs. second alignment layer) to create localized variations in liquid crystal molecule orientation. This local quality differentiation enables the molecules to experience asymmetric forces during switching, accelerating the transition from bended to splay state while improving gray-scale control.
2Speed
If no initial electric field is applied to liquid crystal molecules, then response speed should improve, but switching time from bended state to splay state becomes excessively long (one minute or more)
Solution Approach 1:
The alignment layers are pre-configured with different pretilt angles (first alignment layer: 80-85 degrees, second alignment layer: 85-90 degrees) to create an inherent tendency for liquid crystal molecules to transition from bended state to splay state without requiring initial electric field application. This preliminary structural configuration enables faster response speed while maintaining gray-scale expression capability.
Solution Approach 2:
The patent changes the pretilt angle parameter of the alignment layers from conventional uniform angles to differentiated angles (80-85 degrees vs. 85-90 degrees). This parameter modification creates an energy gradient that drives faster molecular reorientation from bended to splay state, reducing switching time from over a minute to a much shorter duration.
3Ease of manufacture
If uniform pretilt angles are used on both alignment layers, then manufacturing is simplified, but liquid crystal molecule alignment uniformity and response speed are compromised
Solution Approach 1:
The patent applies different pretilt angles at different locations (first alignment layer vs. second alignment layer) to create localized variations in liquid crystal molecule orientation. This local quality differentiation enables the molecules to experience asymmetric forces during switching, accelerating the transition from bended to splay state while improving gray-scale control.
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 reduces the time required for liquid crystal molecules to switch from a bended state to a splay state and improves response speed without the need for an initial electric field, minimizing the twist phenomenon and enhancing uniform directivity.
Implementation Method 1
utilizing a rubbing or optical alignment process to form these layers
Implementation Method 2
utilizing a rubbing or optical alignment process to form these layers
Implementation Method 3
The liquid crystal display applies an electric field to the liquid crystal layer to control an arrangement of liquid crystal molecules
Implementation Method 4
a liquid crystal layer having an anisotropic dielectric constant between the lower and upper substrates
Data Source
AI summary
A liquid crystal display includes first and second substrates, first and second alignment layers, and a liquid crystal layer between the alignment layers and including liquid crystal molecules. The liquid crystal molecules on a surface of the first alignment layer have a first pretilt angle in a direction which is vertical with respect to a horizontal plane surface parallel to the first substrate, and a first alignment angle in a direction which is horizontal with respect to a horizontal line parallel to the horizontal plane surface. The liquid crystal molecules on a surface of the second alignment layer have a second pretilt angle in the direction which is vertical with respect to the horizontal plane surface and different from the first pretilt angle, and a second alignment angle in the direction which is horizontal with respect to the horizontal line and different from the first alignment angle.