FFS Liquid Crystal Display Element Using N-Type Composition
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Solution Overview
Problem
Current liquid crystal display elements for FFS mode struggle with achieving high transmittance and power efficiency due to the limitations of using p-type materials with positive dielectric anisotropy, and there is a need for an n-type liquid crystal composition optimized for FFS mode that addresses alignment direction, electric field direction, and optical characteristics differences from VA mode.
Innovation Solution
A liquid crystal display element configuration using a specific n-type liquid crystal composition with negative dielectric anisotropy, featuring a liquid crystal layer between transparent insulating substrates with a pixel electrode and common electrode structure that induces fringe electric fields, and includes compounds represented by General Formula (I) and (II), ensuring optimal alignment and dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If p-type liquid crystal composition with positive dielectric anisotropy is used in FFS mode, then it is easy to lower the operating voltage, but the major axis of liquid crystal molecules tilts along the fringe electric field, deteriorating transmittance
Solution Approach 1:
The patent changes the dielectric anisotropy parameter from positive to negative by switching from p-type to n-type liquid crystal composition. This parameter change fundamentally alters how the liquid crystal molecules respond to the fringe electric field, allowing the major axis to remain parallel while the minor axis aligns with the electric field, thereby resolving the transmittance deterioration issue while maintaining low operating voltage
Solution Approach 2:
Instead of trying to prevent the tilting effect in p-type materials, the invention inverts the approach by using n-type materials where the polarization direction is perpendicular to the major axis. This inversion causes the minor axis to align with the electric field while the major axis remains parallel, achieving the desired optical properties through opposite material characteristics
2Illumination intensity
If n-type liquid crystal composition is used for FFS mode, then transmittance is improved by maintaining parallel arrangement of major axis, but the composition must be optimized for FFS mode as VA mode compositions are not suitable
Solution Approach 1:
The patent specifies precise parameter ranges for the n-type liquid crystal composition including dielectric anisotropy (Δε: -2.0 to -6.0 at 25°C), refractive index anisotropy (Δn: 0.08 to 0.13 at 25°C), and nematic-isotropic transition temperature (TNI: 60°C or higher). These parameter specifications ensure the composition is optimized for FFS mode operation while maintaining excellent transmittance characteristics
Solution Approach 2:
The patent employs a composite liquid crystal composition containing multiple components with specific structures (compounds of formulas (I), (II), and (III)) that work synergistically. This composite approach allows tuning of multiple parameters simultaneously to achieve the required dielectric properties, optical characteristics, and thermal stability specific to FFS mode operation
3Illumination intensity
If liquid crystal composition is optimized for high transmittance and response speed, then display quality improves, but power consumption increases which conflicts with portable terminal requirements
Solution Approach 1:
The patent achieves a balance between transmittance and power consumption by optimizing the dielectric anisotropy parameter to a specific negative range (-2.0 to -6.0). This parameter optimization allows the liquid crystal to respond efficiently to low voltages while maintaining high transmittance, thereby reducing power consumption without sacrificing display quality - a critical balance for portable terminals
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 results in a high-speed responsive FFS mode liquid crystal display element with reduced display defects and improved transmittance, suitable for applications like liquid crystal TVs and monitors.
Implementation Method 1
a liquid crystal composition having negative dielectric anisotropy... in the case of using the n-type liquid crystal composition, since the polarization direction of the n-type composition is the minor axis direction of the molecules, the influence of the fringe electric field simply rotates the liquid crystal molecules along the major axis and the major axis of the molecule is maintained in a parallel arrangement
Data Source
AI summary
An object of the present invention is to provide a liquid crystal display element using a liquid crystal composition having negative dielectric anisotropy, which is capable of realizing excellent display properties by being used in an FFS mode liquid crystal display element without deteriorating various properties, as a liquid crystal display element, such as dielectric anisotropy, viscosity, a nematic phase upper limit temperature, nematic phase stability at low temperature, and γ1, and burn-in characteristics of the display element.Provided is an FFS mode liquid crystal display element using an n-type liquid crystal composition so as to achieve the above object.