Liquid Crystal Composition Alkenyl Group Limit Residual Images
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Solution Overview
Problem
Liquid crystal displays (LCDs) face issues with residual images due to ion impurities concentrating at the boundary of field generating electrodes, causing refractive anisotropy changes and line residual images, which are not effectively addressed by existing liquid crystal compositions.
Innovation Solution
A liquid crystal composition is developed that includes a fluorine-containing compound and neutral liquid crystal compounds, with a limited content of neutral compounds having an alkenyl group at the terminal group to reduce ion impurity reaction and refractive anisotropy changes, improving the line residual image characteristic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal composition includes neutral liquid crystal compounds with alkenyl groups at the terminal group, then the liquid crystal composition can achieve satisfactory dielectric and refractive anisotropy, but ion impurities react with the alkenyl groups causing refractive anisotropy changes and line residual images
Solution Approach 1:
The patent extracts and removes the harmful alkenyl groups from the neutral liquid crystal compounds. By specifying that neutral liquid crystal compounds should not have alkenyl groups at the terminal group, the invention eliminates the reaction sites for ion impurities, thereby preventing refractive anisotropy changes and line residual images while maintaining other necessary properties.
Solution Approach 2:
The patent changes the chemical structure parameter of neutral liquid crystal compounds by prohibiting alkenyl groups at the terminal position. This structural parameter change prevents ion impurity reactions and extends the line residual image revelation time, resolving the contradiction between maintaining dielectric properties and preventing harmful reactions.
2Ease of manufacture
If the liquid crystal composition uses conventional neutral liquid crystal compounds without structure limitations, then the composition can be simpler and easier to manufacture, but ion impurities concentrate at electrode boundaries causing residual images
Solution Approach 1:
The patent applies local quality by specifically targeting the terminal group of neutral liquid crystal compounds for structural modification. Instead of changing the entire molecule structure, it only restricts the terminal group from having alkenyl groups, thereby maintaining ease of manufacture while preventing ion impurity reactions at critical locations.
3Use of energy by moving object
If the liquid crystal composition includes fluorine-containing compounds and neutral liquid crystal compounds with alkenyl groups, then the composition can achieve desired dielectric anisotropy and refractive index, but the line residual image revelation time is reduced
Solution Approach 1:
The patent converts the potential harm of alkenyl groups (which provide good dielectric properties but cause residual images) into a benefit by selectively removing them. The invention maintains dielectric anisotropy through alternative means while eliminating the harmful effect of ion impurity reactions, thereby extending the line residual image revelation time.
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 composition significantly extends the line residual image revelation time, maintaining satisfactory dielectric and refractive anisotropy, and rotation viscosity, with test displays showing improved performance by limiting the neutral compound with an alkenyl group to less than 7 wt%, resulting in a maximum line residual image revelation time.
Implementation Method 1
neutral liquid crystal compounds having an alkenyl group at the terminal group to reduce ion impurity reaction and refractive anisotropy changes
Implementation Method 2
A voltage is applied to the field generating electrodes to generate an electric field in the liquid crystal layer to determine the direction of liquid crystal molecules
Implementation Method 3
maintaining satisfactory dielectric and refractive anisotropy
Implementation Method 4
refractive anisotropy changes
Data Source
AI summary
The present invention discloses a liquid crystal composition having a first class compound including a fluorine-containing compound, and a second class compound including a neutral liquid crystal compound, where each terminal group of the neutral crystal compound includes an alkyl group, an alkoxy group, or an alkenyl group. If the neutral liquid crystal compound includes an alkenyl group at the terminal group, the liquid crystal composition includes less than 7 wt % of the neutral crystal compound including the alkenyl group. The present invention also discloses a liquid crystal display including the aforementioned liquid crystal composition.