A liquid crystal display device typified by a liquid crystal display panel, a liquid crystal display module or the like utilizes optical anisotropy, dielectric anisotropy or the like of a liquid crystal compound. As an operating mode of the liquid crystal display device, various modes are known, such as a phase change (PC) mode, a twisted nematic (TN) mode, a super twisted nematic (STN) mode, a bistable twisted nematic (BTN) mode, an electrically controlled birefringence (ECB) mode, an optically compensated bend (OCB) mode, an in-plane switching (IPS) mode, a vertical alignment (VA) mode and a polymer sustained alignment (PSA) mode.
Without regard to use according to any mode, any liquid crystal material requires, as common properties, the following characteristics:    1) being stable to external environment factors such as moisture, air, heat and light;    2) exhibiting a liquid crystal phase in a wide temperature range centering on room temperature;    3) having a low viscosity;    4) allowing a decrease of driving voltage when driving a display device;    5) having an optimum dielectric anisotropy (Δ∈); and    6) having an optimum refractive index anisotropy (Δn).