Liquid Crystal Compound for High Refractive Index Anisotropy
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Solution Overview
Problem
Existing liquid crystal compounds face challenges in achieving high refractive index anisotropy while minimizing coloration, particularly in thicker films like cholesteric reflective films, where increased anisotropy often leads to unwanted coloration issues.
Innovation Solution
A compound represented by General Formula (1) with specific substituents and linking groups, such as alkyloxycarbonyl and alkylaminocarbonyl groups, is used to enhance refractive index anisotropy without lengthening absorption wavelengths, allowing for the creation of a composition that forms optically anisotropic bodies and reflective films with improved light fastness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If refractive index anisotropy Δn is increased to reduce film thickness, then the film thickness can be reduced, but coloration occurs particularly in thicker films such as cholesteric reflective films
Solution Approach 1:
The patent modifies the molecular structure parameters of the liquid crystal compound by introducing specific substituents (cyanobiphenyl, tolan, or phenylenediamine groups) to achieve high refractive index anisotropy (Δn ≥ 0.25) while controlling the absorption wavelength to prevent coloration in the visible range
Solution Approach 2:
The patent uses composite molecular structures combining specific liquid crystal compounds with particular functional groups (cyanobiphenyl, tolan, phenylenediamine) to achieve both high Δn and appropriate absorption characteristics, resolving the contradiction between thickness reduction and coloration prevention
2Stability of the object's composition
If conventional liquid crystal compounds are used to achieve high Δn, then refractive index anisotropy can be improved, but absorption wavelength increases causing coloration
Solution Approach 1:
The patent carefully selects and combines specific molecular groups (cyanobiphenyl with 1-10 carbon atoms, tolan, or phenylenediamine) to optimize the balance between refractive index anisotropy and absorption wavelength, ensuring high Δn while keeping absorption in the ultraviolet or near-ultraviolet region
Solution Approach 2:
The patent introduces specific functional groups at particular positions in the liquid crystal molecule to locally enhance refractive index anisotropy without proportionally increasing absorption wavelength, achieving selective improvement of optical properties
Data Source
AI summary
The present invention provides a compound by which high refractive index anisotropy Δn and inhibition of colorability can be compatible. The present invention further provides a composition including the above-mentioned compound, a cured object, an optically anisotropic body, and a reflective film. The compound of the present invention is represented by General Formula (1).