VAIPS Liquid Crystal Display Using Negative Dielectric Anisotropy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices, particularly in the VAIPS mode, face limitations in response speed and viewing angle characteristics, and lack suitable criteria for selecting liquid crystal materials, which hinders performance improvement and adoption in liquid crystal display devices.
Innovation Solution
A liquid crystal display device utilizing a liquid crystal material with negative dielectric anisotropy, featuring vertically aligned or hybrid-aligned liquid crystal molecules, and an electrode structure that allows for efficient domain formation without complex cell configurations, enhancing response speed, viewing angle, and contrast ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If VA mode is used to achieve fast response speed, then response speed is improved, but viewing angle characteristics deteriorate
Solution Approach 1:
The invention divides the liquid crystal layer into multiple domains with different orientation directions. Each domain is formed by partitioning the pixel into multiple sub-pixels, allowing different viewing angles to be optimized for different domains. This segmentation enables the system to achieve both fast response speed (inherent VA mode characteristic) and improved viewing angle characteristics by having multiple domains serve different viewing directions.
Solution Approach 2:
Different regions (domains) within the liquid crystal layer are given different orientation characteristics. By controlling the orientation direction of liquid crystal molecules in each domain through specific electrode patterns and alignment layer treatments, the invention achieves local optimization of viewing angle characteristics while maintaining the fast response speed of VA mode throughout the display.
2Adaptability or versatility
If MVA mode is used to improve viewing angle characteristics, then viewing angle characteristics are improved, but device complexity increases due to complicated cell structure
Solution Approach 1:
Instead of using complex three-dimensional domain structures required by traditional MVA mode, the invention segments the pixel into multiple sub-pixels with simple planar electrode patterns. This segmentation approach achieves multiple domain formation without requiring complicated cell structures, thereby improving viewing angle characteristics while maintaining relatively simple device architecture.
Solution Approach 2:
The invention extracts the essential function of MVA mode (creating multiple domains for different viewing angles) while removing the complicated three-dimensional cell structure. By using planar electrode patterns and alignment layer treatments, the invention achieves domain formation without the complex structural elements that characterize traditional MVA mode, thus simplifying the overall device structure.
3Productivity
If conventional liquid crystal materials with positive dielectric anisotropy are used, then material selection criteria are well-established, but response speed and viewing angle performance are insufficient
Solution Approach 1:
The invention changes the fundamental parameter of dielectric anisotropy from positive to negative. By selecting liquid crystal materials with negative dielectric anisotropy and adjusting other parameters such as viscosity and elastic constants, the invention achieves both fast response speed and wide viewing angle characteristics. This parameter change enables new performance levels while establishing new selection criteria for liquid crystal materials in VAIPS mode.
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 achieves faster response times, wider viewing angles, higher light transmission, reduced light leakage under pressure, and improved contrast ratios compared to conventional technologies, while simplifying the cell configuration and selecting appropriate liquid crystal compositions.
Implementation Method 1
liquid crystal composition having negative dielectric anisotropy
Implementation Method 2
the major axis of the liquid crystal molecules in the liquid crystal composition layer is in a substantial vertical alignment or a hybrid alignment
Implementation Method 3
the threshold voltage (Vc) of Fréedericksz transition in a twisted nematic (TN) mode
Data Source
AI summary
Provided is a liquid crystal display device of VAIPS mode, which uses a liquid crystal material having negative dielectric anisotropy (&Dgr;∈<0), and has a high response speed, a wide viewing angle, a high transmittance at the time of light transmission, a high black level at the time of light blockage, and an excellent contrast ratio. Disclosed is a liquid crystal display device including a first substrate, a second substrate, and a liquid crystal composition layer having negative dielectric constant, which is interposed between the first substrate and the second substrate, the liquid crystal display device being an electro-optical display device which has a plurality of pixels, and in which each of the pixels is independently controllable and has a pair of a pixel electrode and a common electrode, the two electrodes are provided on at least one substrate of the first substrate and the second substrate, and the long axis of the liquid crystal molecules of the liquid crystal composition layer is in a substantial vertical alignment or a hybrid alignment with respect to the substrate surface.