Liquid Crystal Compound for High Δn Optical Layers
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Solution Overview
Problem
Current liquid crystal compounds with high refractive index anisotropy (Δn) are limited in their ability to form optically anisotropic layers with desired alignment patterns, especially when mixed with other compounds lacking liquid crystallinity, which restricts their applications in optical elements and light guide elements.
Innovation Solution
A compound represented by General Formula (I) is developed, which can exhibit high refractive index anisotropy (Δn) and liquid crystallinity, allowing it to form optically anisotropic layers with specific alignment patterns even when mixed with other compounds, by incorporating polymerizable groups and specific linking groups, enabling the creation of optically anisotropic bodies and light guide elements with enhanced diffraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid crystal compound with high refractive index anisotropy (Δn) is used, then diffraction efficiency is improved, but the ability to form optically anisotropic layers with desired alignment patterns deteriorates when mixed with other compounds
Solution Approach 1:
The patent modifies the molecular structure parameters of the liquid crystal compound by introducing polymerizable groups (acryloyloxy or methacryloyloxy) at specific positions (para positions of phenyl rings) and selecting specific linking groups (—O—, —S—, —SO2—, —COO—, —OCO—) to achieve both high Δn (0.28 or more) and liquid crystallinity, enabling the compound to maintain alignment pattern formation capability while mixing with other compounds
Solution Approach 2:
The patent creates a composite liquid crystal composition by mixing the compound of formula (I) with other liquid crystal compounds or compounds lacking liquid crystallinity. The compound of formula (I) acts as a key component that imparts both high refractive index anisotropy and liquid crystallinity to the mixture, enabling the formation of optically anisotropic layers with desired alignment patterns even when mixed with up to 95 mass% of other compounds
2Adaptability or versatility
If a compound with high refractive index anisotropy is mixed with other compounds lacking liquid crystallinity, then compositional flexibility is improved, but the formation of optically anisotropic layers deteriorates
Solution Approach 1:
The patent modifies the molecular structure parameters of the liquid crystal compound by introducing polymerizable groups (acryloyloxy or methacryloyloxy) at specific positions (para positions of phenyl rings) and selecting specific linking groups (—O—, —S—, —SO2—, —COO—, —OCO—) to achieve both high Δn (0.28 or more) and liquid crystallinity, enabling the compound to maintain alignment pattern formation capability while mixing with other compounds
Solution Approach 2:
The compound of formula (I) possesses inherent liquid crystallinity and high refractive index anisotropy, enabling it to self-organize into optically anisotropic layers with desired alignment patterns even when mixed with compounds lacking liquid crystallinity. The polymerizable groups allow the compound to undergo photopolymerization, fixing the alignment pattern and maintaining the optically anisotropic structure
3Stability of the object's composition
If polymerizable groups and specific linking groups are incorporated into the compound structure, then liquid crystallinity and solubility are improved, but molecular structure complexity increases
Solution Approach 1:
The patent modifies the molecular structure parameters of the liquid crystal compound by introducing polymerizable groups (acryloyloxy or methacryloyloxy) at specific positions (para positions of phenyl rings) and selecting specific linking groups (—O—, —S—, —SO2—, —COO—, —OCO—) to achieve both high Δn (0.28 or more) and liquid crystallinity, enabling the compound to maintain alignment pattern formation capability while mixing with other compounds
Solution Approach 2:
The patent applies local quality by placing polymerizable groups (acryloyloxy or methacryloyloxy) specifically at the para positions of phenyl rings in the molecular structure, rather than throughout the entire molecule. This localized modification enables liquid crystallinity and photopolymerization capability while maintaining relative simplicity in other parts of the molecule, such as using simple linking groups (—O—, —S—, —SO2—, —COO—, —OCO—) between the core aromatic rings
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 achieves high refractive index anisotropy and improved solubility, leading to the formation of optically anisotropic layers with high diffraction efficiency and durability, suitable for various optical applications including augmented reality devices and light guide elements.
Implementation Method 1
a compound having liquid crystallinity (hereinafter, also referred to as a 'liquid crystal compound')
Implementation Method 2
diffracted light with high diffraction efficiency can be obtained at a large diffraction angle by an optical element including an optically anisotropic layer consisting of a cured product of a composition containing a liquid crystal compound
Implementation Method 3
P1 and P2 each independently represent a hydrogen atom, —CN, —NCS, or a polymerizable group
Data Source
AI summary
There is provided a compound represented by General Formula (I), a composition containing the compound represented by General Formula (I), a cured product, an optically anisotropic body, an optical element, and a light guide element. P1 and P2 each independently represent a hydrogen atom, —CN, —NCS, or a polymerizable group. Sp1 and Sp2 each independently represent a single bond or a specific linking group, Z1 represents a specific linking group. However, two or more Z1's represent —C≡C—. Two Z's bonded to A2 in —Z-A2-Z— in General Formula (I) do not represent —C≡C—. A1 and A2 each independently represent a specific group. A plurality of A2's may be the same or different from each other. n represents an integer of 3 to 7.