Liquid crystal mixtures having a net positive dielectric anisotropy comprise a weakly polar ( DELTA epsilon /=3) anisotropic non-cyano component (A) and a strongly polar (( DELTA epsilon /=5) anisotropic cyano component (B), the mixture of (A) and (B) containing from 50 to 95 mole % of component (B). Component (A) consists of not more than 5 compounds of the formula: (I) R1-A1-Z1[A2-Z2]m-A3-R2 and component (B) consists of not more than 5 compounds of the formula R3-A4-Z3-[A5-Z4]p-A6-CN (III in which formulae: R1, R2 and R3 are the same or are different and each is an n-alkyl, n-alkoxy, n- alkylamino, n-acyloxy or n-alkoxycarbonyl group containing not more than 12 carbon atoms in a chain (provided that component (A) consists of compounds in which one of R1 and R2 is a group containing not more than three atoms in a chain or component (B) consists of compounds in which R3 is a group containing not more than three atoms in a chain); A1, A2, A3 and A4 is each a ring of the formula: IMAGE m is 0, 1 or 2; p is 0 or 1; and Z1, Z2, Z3 and Z4 are the same or are different and each is a covalent bond or a methylenoxy, ethylene, or carboxyl group (provided that Z1 and Z2 and/or Z3 and Z4 are not both carboxyl groups and Z3 is not a carboxyl group when, p is zero and either A4 and A6 are both rings of formula (1a) or A4 is a ring of formula (1b).
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机译：具有净正介电各向异性的液晶混合物包含弱极性（DELTA epsilon / = 5）各向异性的氰基组分（B）， （A）和（B）的混合物含有50-95摩尔％的组分（B），组分（A）由不超过5种下式的化合物组成：（I）R 1 -A 1- Z 1 [A 2 -Z 2] mA 3 -R 2和组分（B）由不超过5种式R 3 -A 4 -Z的化合物组成<3>-[A 5 -Z 4] pA 6 -CN（III）其中，式：R 1，R 2和R 3相同或不同，各自是在链中包含不超过12个碳原子的正烷基，正烷氧基，正烷基氨基，正酰氧基或正烷氧基羰基（条件是组分（A）由其中R 1之一的化合物组成） R 2为链中含有不超过三个原子的基团或组分（B）由化合物组成，其中R 3为链中含有不超过三个原子的基团）; <1>，A <2>，A <3>和A <4>分别为下式的环： m为0、1或2; p为0或1; Z 1，Z 2，Z 3和Z 4相同或不同，分别为共价键或亚甲基氧基，亚乙基或羧基（只要Z 1和Z当p为零且A 4和A 6均为环的环时，<2>和/或Z 3和Z 4既不是羧基，Z 3也不是羧基。式（1a）或A 4为式（1b）的环。
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