| 摘要 |
PROBLEM TO BE SOLVED: To obtain a liq. crystal medium having a very high resistivity and a low threshold voltage by using a mixture of polar compds. having specified positive dielectric anisotropies. SOLUTION: At least one compd. selected from among compds. of formula I is used, and at least one compd. selected from among compds. of formulas II to IV is also used. In the formulas, A1 and A2 are each trans-1,4- cyclohexylene, 1,4-phenylene, or 3-fluoro-1,4-phenylene; Z is -CH2CH2-; L, Y, and X are each F; R is a 7C or lower alkyl, oxaalkyl, fluoroalkyl, or alkenyl group; X' is F, Cl, CF3, OCF3, or OCHF2; L' and Y' are each H or F; and (r) is 0 or 1. Normally, the sum of proportions of the compds. of formula I to IV is at least 50 wt.% of the mixture; the proprtion of the compd. of formula I is at least 10-50 wt.%; and the sum of proportions of the compds. of formulas II to IV is 30-70 wt.%.
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