Difluorovinyl Liquid Crystal Diluters Improve the Electro-Optical Properties of High-∆In/I Liquid Crystal Mixture for AR Displays

• Published in: Molecules (Basel, Switzerland) Switzerland), 2023-03, Vol.28 (6)
• Main Authors: Tang, Jiaxing, Mao, Zihao, An, Zhongwei, Chen, Ran, Chen, Xinbing, Chen, Pei
• Format: Article
• Language: English
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28062458

A liquid crystal (LC) mixture in liquid crystal on silicon (LCoS) is the core material for augmented reality (AR) displays. However, a LC mixture with high birefringence (Δn) and large dielectric anisotropy (Δε) possesses high viscosity (γ[sub.1]), which results in a slow response time of LCoS devices for AR displays. This work proposes to apply difluorovinyl-based LC diluters to fine balance the low viscosity, high ∆n, and large ∆ε of the LC mixture for a fast response time. Through studying their effects on the key electro-optical properties of a high-∆n LC mixture, it is found that doping these diluter molecules to a high-∆n LC mixture can decrease the viscoelastic coefficient (γ[sub.1]/K[sub.11]), increase ∆ε and the figure of merit, maintain a wide nematic phase temperature range, a high clearing point, and ∆n. It also means that these diluters could effectively regulate the relationship between ∆n, ∆ε, and γ[sub.1] in the LC mixtures to achieve a fine balance of various excellent properties and further improve the LC device's response time. The widespread applications of these liquid crystal diluters in emerging liquid crystal optical devices are foreseeable.