The temperature dependencies of three low birefringence (Δn) liquid crystals (LCs) at similar clearing temperatures
(TNI)were investigated to characterize the order parameter S(T) and crossover temperature (Tco). Three different
methods were used to determine the S(T) property, including the Vuks model, the Haller approximation
model, and a model based on the effective geometry parameter (αeg). In our lowΔn LCswith relatively analogous
TNI, three parameters (B, (Δn)o, andβ) that originated fromthe modified four-parametermodel were analyzed to
increase the Tco condition. A larger absolute value for the B parameter and a smaller β parameterwere also needed
to reduce the temperature dependence of Δn. In particular, a lower (Δn)o value was found to be beneficial for
increasing the Tco value, which resulted in a higher Tco value for the low Δn LCs, compared with that of a high Δn
LC with a similar TNI value. This led to a narrower temperature range between Tco and TNI for the lowΔn LCs compared
to that of the high Δn LC,which could result in appropriate temperature properties for LCs for practical display
applications, including a lower temperature dependence of Δn and wider operational temperature regime.
کلید واژگان :
Liquid crystal Refractive index Birefringence Order parameter Effective geometry parameter Crossover temperature
