申请人:MERCK PATENT GmbH
公开号:EP0700983A2
公开(公告)日:1996-03-13
The invention relates to an electrooptical liquid crystal system
which contains a dielectrically positive liquid crystal mixture and a further optically transparent medium between 2 electrodes which are optionally applied to substrate sheets,
whose liquid crystal molecules in the switched-off state have an irregular orientation,
in which one of the refractive indices of the liquid crystal mixture essentially agrees with the refractive index of the matrix nM and/or in which the quotient of the mass of the liquid crystal mixture and of the mass of the optically transparent medium is 1.5 or more and,
which, independently of the polarization of the incident light, has a reduced transmission in one of the two switch states compared to the other state and
whose liquid crystal mixture contains one or more compounds of the formula I
in which
Q¹is
are independently of one another trans-1,4-cyclohexylene, 1,4-phenylene, 2-fluoro-1,4-phenylene, 3-fluoro-1,4-phenylene, 3,5-difluoro-1,4-phenylene and one of A¹ and, if present, A², is also pyridine-2,5-diyl, pyrimidine-2,5-diyl, 1,3-dioxane-2,5-diyl, tetrahydropyran-2,5-diyl or naphthalene-2,6-diyl,
Z¹ and Z²are independently of one another a single bond, -CH₂CH₂-, -COO-, -OCO-, -C≡C-, -CH₂O- or any desired combinations of these bridge groups,
Y and Xare independently of one another H or F, and one of X and Y is also Cl,
Wis -CN, -Cl, -F, -CF₃, -OCF₃ or -NCS
R¹is alkyl having 1-12 C atoms, in which one or 2 non-adjacent CH₂ groups can also be replaced by -O- or -HC=CH-, and
mis 0, 1 or 2,
with the proviso that at least one of X and Y is F and/or at least one of A¹ and A² is 2-fluoro-, 3-fluoro- or 3,5-difluoro-1,4-phenylene.
本发明涉及一种光电液晶系统
该系统在两个电极之间包含一个正电液晶混合物和另一个光学透明介质,这两个电极可选择安装在基片上、
其液晶分子在关断状态下具有不规则的取向、
其中一种液晶混合物的折射率与基质 nM 的折射率基本一致,和/或液晶混合物的质量与光学透明介质的质量之比为 1.5 或以上,以及
与入射光的偏振无关,在两种切换状态中,一种状态的透射率比另一种状态的透射率低,且
其液晶混合物含有一种或多种式 I 的化合物
其中
Q¹为
是相互独立的反式-1,4-环己烯、1,4-亚苯基、2-氟-1,4-亚苯基、3-氟-1,4-亚苯基、3,5-二氟-1,4-亚苯基,且 A¹ 和 A² 中的一个也是吡啶-2,5-二基、嘧啶-2,5-二基、1,3,3-亚苯基、也是吡啶-2,5-二基、嘧啶-2,5-二基、1,3-二噁烷-2,5-二基、四氢吡喃-2,5-二基或萘-2,6-二基、
Z¹ 和 Z² 相互独立地为单键、-CH₂CH₂-、-COO-、-OCO-、-C≡C-、-CH₂O- 或这些桥基的任意组合、
Y 和 X 相互独立地为 H 或 F,X 和 Y 中的一个也是 Cl、
之-CN、-Cl、-F、-CF₃、-OCF₃ 或 -NCS
R¹ 是具有 1-12 个 C 原子的烷基,其中一个或两个不相邻的 CH₂ 基团也可以被-O-或-HC=CH-取代,以及
误差为 0、1 或 2、
条件是 X 和 Y 中至少有一个是 F 和/或 A¹ 和 A² 中至少有一个是 2-氟、3-氟或 3,5-二氟-1,4-亚苯基。