Novel smectic phase A liquid crystal material

Abstract

The invention relates to a novel smectic phase A liquid crystal material which comprises at least one heterocyclic compound shown as a formula (I), in which X and Z are benzene rings, F is a fluorine atom, any one hydrogen atom on the benzene rings can be substituted by the fluorine atom. When Y is the benzene ring, T is a nitrogen atom, and any one carbon atom on the benzene ring can be substituted by the nitrogen atom. When Y is a cyclohexyl ring, T is an oxygen atom, a sulfur atom and / or a boron atom, any one carbon atom on the cyclohexyl ring can be substituted by the oxygen atom, the sulfur atom and / or the boron atom. The smectic phase A liquid crystal material provided by the invention further comprises at least one ester compound and an ester compound shown as the a formula (II). By applying the material to a display apparatus, displayed images placed or driven to use for a long time can be completely erased without ghosts, the contrast of the display apparatus is high and is commonly greater than 10, and the driving voltage is low and is commonly 20-50V.

Description

technical field [0001] The invention relates to a novel smectic A-phase liquid crystal material, which belongs to the technical field of optical display materials. Background technique [0002] Liquid crystals are mainly divided into different phases: nematic phase, smectic phase, cholesteric phase, and smectic phase is divided into smectic A, B, C, D, E, F, G, H, I, G and so on. Nematic and cholesteric liquid crystals have low viscosity and have obvious fluidity, while smectic liquid crystals have relatively high viscosity. Liquid crystals have dielectric anisotropy, and liquid crystal molecules can be driven by an electric field. After the liquid crystal molecules with low viscosity are driven by the electric signal, due to the low viscosity, the molecular arrangement cannot be maintained after the electric signal is cut off, and the original arrangement state can be restored; but after the liquid crystal molecules with high viscosity are driven by the electric signal, du...

AI Technical Summary

Problems solved by technology

[0005] However, the siloxane-based smectic A-phase liquid crystal has a strong memory effect, and the displayed image cannot be completely erased, and it is easy to leave afterimages of the displayed image (as shown in Figure 1b)

In addition, since the birefringence of the siloxane-based smectic A phase material itself is very small (Δn≈0.08), and the amount of siloxane liquid crystals used in the formula is large, the smectic A phase mainly composed of siloxane Liquid crystal formula birefringence is not high

In the scattering display mode, the contrast is related to the birefringence of the liquid crystal material. The larger the birefringence, the higher the contrast. Therefore, the contrast of siloxane smectic A phase materials is poor when used as a display.

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