| 摘要 |
Liquid crystal compositions which comprise as a first component at least one compound selected from the group of compounds represented by the formula (I) and as a second component at least one compound selected from the group of compounds represented by the formula (II), the content of the first component being not less than 30% by weight based on the total weight of the compositionwherein R<1 >and R<3 >are independently an alkyl of 1 to 10 carbon atoms and any -CH2- in the alkyl may be replaced by -O- or -CH=CH-; R<2 >is an alkyl of 1 to 10 carbon atoms, -F or -Cl; X<1>, X<2>, X<3>, X<4>, X<5>, X<6>, X<7>, X<8 >and X<10 >are independently -F or -H; X<9 >is -F, -Cl, -CF3, -OCF3 or -OCF2H; A<1 >and A<2 >are independently 1,4-cyclohexylene, pyrimidine-2,5-diyl or 1,4-phenylene in which any -H may be replaced by -F; Z<1 >and Z<3 >are independently a single bond, -(CH2)2- or -(CH2)4-; Z<2 >is a single bond or -CF2O-; and Z<4 >is a single bond, -COO- or -CF2O-. These compositions have reduced response time and low threshold voltage, and are used in a liquid crystal display device, especially that of an OCB mode.
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