Terminal groups enhance the birefringence and dielectric anisotropy of fluorinated terphenyl liquid crystals for AR displays
Laser display technology can enhance the image quality of liquid–crystal on silicon (LCoS) devices in AR displays. High birefringence (Δ n ), large dielectric anisotropy (Δ ε ), low rotational viscosity ( γ 1 ) and good blue-light stability are inevitable performance requirements for achieving fast response time, low voltage and 2π phase modulation in LCoS devices based on laser display technology. However, people lack attention to how to obtain liquid crystal compounds with above properties. In this work, we propose to utilize one fluorinated terphenyl unit with excellent blue-light stability as the molecular skeleton, and then employ large polar terminal groups to modulate the molecular polarizability and dipole moment , and finally screen to obtain the LCs with high Δ n and large Δ ε . The effects of methyl, fluorinated, chlorinated and cyano terminal groups on the mesomorphic and electro-optical properties of fluorinated terphenyl LCs were systematically studied. Experimental and theoretical results show that the target compounds exhibit wide LC phase intervals, and could enhance the Δ n , Δ ε of the parent LC mixture and reduce its viscoelastic constant, further meaning that they would help to improve the electro-optical properties of LC mixtures for AR displays. Our results would provide experimental data and technical support for the future development of LC mixtures with high blue-light stability for AR displays.
危险品化学品经营许可证（带存储）