Polyolefin Alignment Layer for VA Display Afterimage
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Solution Overview
Problem
Vertically aligned liquid crystal displays face challenges with side visibility and rapid response speed, particularly in achieving a wide viewing angle and improved mechanical properties to prevent afterimage issues.
Innovation Solution
An alignment layer incorporating a polyolefin-based compound with side chains and reactive mesogens is used, which includes a backbone with specific chemical formulations to enhance mechanical properties and induce pretilt in liquid crystal molecules, improving alignment and reducing afterimage effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a vertically aligned liquid crystal display is used to achieve large contrast ratio and wide reference viewing angle, then the contrast ratio and reference viewing angle are improved, but side visibility deteriorates
Solution Approach 1:
The patent divides one pixel into two sub-pixels with different voltages applied to each, creating multiple domains within a single pixel. This segmentation allows different viewing angle characteristics to be achieved in different regions, improving side visibility while maintaining the vertically aligned mode's contrast ratio and reference viewing angle advantages.
Solution Approach 2:
The alignment layer is designed with specific local properties including polyolefin-based compounds with reactive mesogens that create pretilt angles. This local quality control at the molecular level enables precise manipulation of liquid crystal orientation in different regions, addressing the side visibility issue while preserving the overall vertically aligned configuration's high contrast ratio.
2Reliability
If conventional alignment materials are used in vertically aligned liquid crystal displays, then the basic alignment function is achieved, but mechanical properties deteriorate causing afterimage issues
Solution Approach 1:
The patent employs composite materials in the alignment layer, specifically combining polyolefin-based compounds with reactive mesogens. This composite structure provides both the necessary alignment function for vertically aligned liquid crystal displays and enhanced mechanical properties including improved strength and resistance to afterimage effects, overcoming the limitations of conventional single-material alignment layers.
Solution Approach 2:
The invention changes the chemical and physical parameters of the alignment layer by using polyolefin-based compounds with specific molecular weights and densities. These parameter changes result in improved mechanical properties and reduced afterimage effects while maintaining the required alignment function, directly addressing the contradiction between reliability and strength.
3Stability of the object's composition
If conventional alignment layers are used to achieve vertical alignment, then the basic alignment is achieved, but response speed deteriorates
Solution Approach 1:
The alignment layer is designed to create a pretilt in the liquid crystal molecules before voltage application. This preliminary action of pre-orienting the molecules at specific angles reduces the time required for reorientation when voltage is applied, thereby improving response speed while maintaining stable vertical alignment in the off-state.
Solution Approach 2:
By changing the molecular structure and composition parameters of the alignment layer using polyolefin-based compounds, the patent optimizes the interaction between the alignment layer and liquid crystal molecules. This enables faster response speeds while preserving the stable vertical alignment characteristic, resolving the contradiction between alignment stability and response speed.
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 alignment layer with a polyolefin-based compound improves mechanical properties and afterimage performance by increasing molecular weight and density, effectively addressing side visibility and response speed limitations in vertically aligned liquid crystal displays.
Implementation Method 1
a method of manufacturing an alignment layer, the method may include forming the alignment layer on at least one of a first substrate and a second substrate facing each other and including an electric field generating electrode; and injecting a liquid crystal layer between the first substrate and the second substrate, wherein the alignment layer may be manufactured by the following Reaction Formula 1
Data Source
AI summary
The present invention provides an alignment layer including a backbone including a polyolefin-based compound, and a plurality of side chains including a vertical functional group and a reactive mesogen (RM) and connected to the backbone, the backbone and the plurality of side chains include a compound represented by the following Chemical Formula 1, and a liquid crystal display including the alignment layer. According to the present invention, the alignment layer may have improved mechanical properties and afterimage by including a polyolefin-based compound as a backbone.Wherein X, Y, Z, Ak, Ar, Ra, and a, b, c, d and e are defined as in the specification.