Liquid-Crystal Medium for IPS Displays with Low Voltage
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Solution Overview
Problem
Current liquid-crystal displays using dielectrically negative liquid crystals for IPS and FFS effects require higher operation voltages and have limitations in transmission, response time, and stability, particularly in mobile applications, where high specific resistance, broad temperature range, and low threshold voltage are essential for efficient and stable performance.
Innovation Solution
A liquid-crystal medium comprising compounds with specific dielectric properties, including high dielectric constants and anisotropy, is developed, featuring a mixture of polar compounds with a dielectric ratio of ε⊥ / Δε ≤ 2.0 and ε⊥ ≥ 3.8, which enhances transmission, reduces response time, and improves stability under extreme temperatures and UV exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If dielectrically negative liquid crystals are used for IPS and FFS displays, then transmission is markedly increased, but operation voltage becomes higher
Solution Approach 1:
The patent changes the dielectric parameter of the liquid crystal medium from negative to positive, specifically using compounds with high dielectric constant (ε⊥ ≥ 3.8) and low dielectric ratio (ε⊥/Δε ≤ 2.0). This parameter change enables the display to achieve high transmission while maintaining low operation voltage, as the positive dielectric anisotropy allows for more efficient electric field control of the liquid crystal molecules.
Solution Approach 2:
The patent employs composite liquid crystal mixtures containing multiple compounds with specific dielectric properties. The mixture includes dielectrically positive compounds with high dielectric constant and low dielectric ratio, combined with other liquid crystal compounds to achieve the desired overall performance. This composite approach allows optimization of both transmission and operation voltage characteristics.
2Productivity
If conventional liquid crystalline media are used, then manufacturing is simpler, but response time is longer and transmission is lower
Solution Approach 1:
The patent optimizes multiple physical parameters of the liquid crystal medium simultaneously: dielectric constant (ε⊥ ≥ 3.8), dielectric ratio (ε⊥/Δε ≤ 2.0), and viscosity. These parameter changes result in faster response time due to reduced rotational viscosity and improved dielectric response, while also achieving higher transmission through optimized optical anisotropy and molecular alignment properties.
3Productivity
If dielectrically positive liquid crystals with high dielectric constant are used, then response time is reduced, but operation voltage increases
Solution Approach 1:
The patent carefully balances the dielectric constant and dielectric ratio parameters to achieve optimal performance. By selecting compounds with high dielectric constant (ε⊥ ≥ 3.8) combined with low dielectric ratio (ε⊥/Δε ≤ 2.0), the patent achieves fast response time through high dielectric response while maintaining low operation voltage through efficient molecular reorientation. This precise parameter control resolves the contradiction between response speed and energy consumption.
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 low threshold voltage, short response times, and high transmission with excellent stability and holding ratio, suitable for various applications including mobile devices, by leveraging the unique dielectric properties of the liquid-crystal medium.
Implementation Method 1
The liquid-crystal media according to the invention have a positive dielectric anisotropy and comprise compounds having at the same time large dielectric constants parallel and perpendicular to the molecular director
Implementation Method 2
The liquid-crystal displays, particularly to liquid-crystal displays which use the IPS (in-plane switching) or, preferably, the FFS (fringe field switching) effect
Implementation Method 3
The media are distinguished by a particularly high transmission and reduced response time in respective displays, which is brought about by their unique combination of physical properties, especially by their dielectric properties
Data Source
AI summary
The invention relates to a liquid-crystalline medium having a nematic phase comprising one or more compounds of formula X wherein the parameters have the meaning given in the text, to the use thereof in an electro-optical display, particularly in an active-matrix display based on the IPS or FFS effect, to displays of this type which contain a liquid-crystalline medium of this type and to the use of the compounds of formula X for improvement of the transmission and/or response times of a liquid-crystalline medium which comprises one or more additional mesogenic compounds, as well as to the compounds of formula X.