| abstract |
The invention relates to a liquid crystalline medium based on a mixture of polar compounds with positive dielectric anisotropy, characterised in that it contains at least one compound of formula (I) and at least one compound of formula (IA) wherein R1, R2, ring A, ring B, L1-4, Z1-4, Z1, Z2, X1, X2 and a have the designations cited in claim (1), the part of the compounds of formula (I) in the medium amounting to at least 18 wt. %. |