The invention provides a liquid crystal compound having stability to heat, light and so forth, a wide temperature range of a nematic phase, a small viscosity, a suitable optical anisotropy, a suitable elastic constant K33, a suitable and negative dielectric anisotropy, and an excellent compatibility with other liquid crystal compounds. The invention provides a liquid crystal composition containing the compound described above and having stability to heat, light and so forth, a small viscosity, a suitable optical anisotropy, a suitable and negative dielectric anisotropy, a suitable elastic constant K33, a low threshold voltage, a high maximum temperature of a nematic phase, and a low minimum temperature of the nematic phase.
The invention also provides a liquid crystal display device having a short response time, a small power consumption, a low driving voltage, and a large contrast, and containing the composition described above which can be used in a large temperature range.
For example, a liquid crystal compound having four or more rings in which the central ring has 2,3-difluorophenoxy such as trans-4'-[2,3-difluoro-4-(trans-4-propylcyclohexyl)phenoxymethyl]-trans-4-pentylbicyclohexyl is provided. Further provided is a liquid crystal composition containing the compound, and a liquid crystal display device using this liquid crystal composition.
本发明提供了一种液晶化合物,它具有对热、光等的稳定性,向列相温度范围宽, 粘度小,适当的光学各向异性,适当的弹性常数 K33,适当的负介电各向异性,以及与 其他液晶化合物的良好兼容性。本发明提供了一种含有上述化合物的液晶组合物,该组合物具有对热、光等的稳定性、较小的粘度、适当的光学各向异性、适当的负介电各向异性、适当的弹性常数 K33、较低的阈值电压、向列相的最高温度较高以及向列相的最低温度较低。
本发明还提供了一种液晶显示装置,其响应时间短、功耗小、驱动电压低、对比度大,且含有上述成分,可在较大温度范围内使用。
例如,提供了一种具有四个或四个以上环的液晶化合物,其中中心环具有 2,3-二
氟苯氧基,例如反式-4'-[2,3-二
氟-4-(反式-4-丙基环己基)苯氧基甲基]-反式-4-戊基二环己基。此外,还提供了一种含有该化合物的液晶组合物,以及一种使用该液晶组合物的液晶显示设备。