Liquid Crystal Compound with Polar and Polymerizable Groups
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Solution Overview
Problem
Current liquid crystal display elements face challenges in achieving high chemical stability, efficient alignment of liquid crystal molecules, and long-term stability under UV radiation, while also requiring low viscosity and high dielectric anisotropy for optimal performance.
Innovation Solution
A compound represented by Formula (1) is introduced, which contains a polar group and multiple polymerizable groups, allowing for high solubility and reactivity under UV radiation, and is incorporated into a liquid crystal composition to enhance the alignment and stability of liquid crystal molecules, thereby improving the performance of liquid crystal display elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal composition uses conventional compounds without both polar groups and polymerizable groups, then the manufacturing process is simpler, but the chemical stability and alignment performance are insufficient
Solution Approach 1:
The patent combines a polar group (for alignment and chemical stability) and polymerizable groups (for UV crosslinking and long-term stability) into a single liquid crystal compound molecule. This merging allows the compound to simultaneously provide alignment functionality, chemical stability, and polymerization reactivity, resolving the contradiction between reliability and device complexity.
Solution Approach 2:
The liquid crystal compound represents a composite molecular structure integrating multiple functional groups (polar groups and polymerizable groups) that would traditionally require separate additives. This composite approach achieves enhanced chemical stability and alignment performance without proportionally increasing manufacturing complexity.
2Speed
If the liquid crystal composition has low viscosity for short response time, then the response time is reduced, but the dielectric anisotropy may be insufficient for high voltage holding ratio
Solution Approach 1:
The patent optimizes molecular parameters of the liquid crystal compound, including the selection of specific ring structures (cyclohexyl, phenyl, naphthyl), spacer lengths, and substituent groups to achieve a balance between viscosity and dielectric anisotropy. By carefully adjusting these molecular parameters, the composition achieves both fast response time and high voltage holding ratio.
3Reliability
If the liquid crystal display element uses UV radiation for polymerization to improve stability, then the long-term stability is enhanced, but the chemical stability during storage may be compromised
Solution Approach 1:
The liquid crystal compound is pre-synthesized with polymerizable groups in the desired configuration before use. This preliminary preparation allows the compound to be stored in its monomeric liquid crystal state with appropriate stability, and then undergo controlled polymerization upon UV irradiation during device fabrication, achieving both storage stability and long-term durability.
Solution Approach 2:
The molecular structure is designed with sufficient chemical stability to withstand storage conditions, while the polymerizable groups remain dormant until UV activation. This beforehand cushioning ensures the composition remains stable during storage and transport, then transforms into a crosslinked stable network after UV irradiation.
4Use of energy by moving object
If the liquid crystal composition has high dielectric anisotropy for low threshold voltage, then the power consumption is reduced, but the optical anisotropy may be compromised affecting contrast ratio
Solution Approach 1:
The patent carefully adjusts molecular parameters including the selection of anisotropic ring structures, spacer configurations, and substituent groups to optimize both dielectric anisotropy and optical anisotropy simultaneously. By changing these molecular parameters, the composition achieves the desired balance between low threshold voltage and high contrast ratio.
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 compound improves the chemical stability, alignment, and long-term stability of liquid crystal display elements, achieving a wide temperature range, short response time, high voltage holding ratio, and increased contrast ratio, while maintaining solubility and reactivity.
Implementation Method 1
the compound having both an -OH group and a plurality of polymerizable groups such as a methacryloyloxy group... high polymerization reactivity according to ultraviolet radiation
Data Source
AI summary
To provide a compound having, for example, high chemical stability, a high ability to align liquid crystal molecules, or high solubility in a liquid crystal composition. A compound represented by Formula (1): R1 is a hydrogen atom or an optionally substituted alkyl group; rings A1 and A2 are an optionally substituted cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclohexenylene, phenylene, naphthalenediyl, decahydronaphthalenediyl, tetrahydronaphthalenediyl, tetrahydropyrandiyl, dioxanediyl, pyrimidinediyl or pyridinediyl group; a is 0 to 4; Z1 is a single bond or an optionally substituted alkylene group; Sp1 to Sp5 are a single bond or an optionally substituted alkylene group; M1 to M4 are H, F, Cl, or an optionally substituted alkyl group; R2 is an optionally substituted alkyl group having 1 to 5 carbon atoms; and X1 is -OH, -NH2, -OR3, -N(R3)2, -COOH, -SH or -Si(R3)3.