| 摘要 |
<p>Liquid crystal composition having a high voltage-holding ratio of liquid crystal element and being almost unchanged in the helical pitch even when subjected to purification treatment with adsorbents or the like, which composition is a liquid crystal mixture of an achiral liquid crystal compound of the following formula (IV) with a chiral compound having an adsorptivity to adsorbents, not greater than that of the achiral compound: <CHEM> wherein A', B', C' and D' each independently are trans-1,4-cyclohexylene, 1-cyclohexene-1,4-diyl or 1,4-phenylene; g, h and i each are 0 or 1; (g+h+i)>/=1; X', Y' and Z' each independently are a single bond, -CH2-CH2-, -CH=CH- or -C IDENTICAL C-; R<7> is CnH2n+1-, CnH2n-1 or CnH2n+1OCkH2k-; R<8> is CmH2m+1-, CmH2m+1O-, F, CHF2O or CF3O-; n and m each independently are an integer of 1 to 18; k is an integer of 1 to 17; (n+k) is 2 to 18; at least one of X', Y' and Z' is single bond; when ring D' is 1,4-phenylene and R<8> is F, CHF2O- or CF3O-, then H at ortho position as regards R<8> may be replaced by F; and "Then" g is 1 and ring B' or C' is 1,4-phenylene, when H at the lateral position of the ring may be replaced by F. It is preferred in order to exhibit a high voltage-holding ratio that the achiral liquid crystal compound have as a polar group, a functional group (such as F and CF3O-) limited to a halogen atom such as F, C l , etc. or an ether bond, besides the C-C bond and the C-H bond. As to chiral compounds those having a functional group restricted to only a halogen atom or an ether bond are preferred, in the same aspect, chiral agent compounds having a polar group of -CN group as a fuctional group are unsuitable.</p> |
