Patent ID: 8216489

Claim:
A liquid crystal compound represented by formula (a-1): wherein R 1 and R 2 are each independently hydrogen, alkyl having 1 to 10 carbons, alkenyl having 2 to 10 carbons, alkoxy having 1 to 9 carbons, alkoxyalkyl having 2 to 9 carbons or alkenyloxy having 2 to 9 carbons; ring A 1 is trans-1,4-cyclohexylene, 1,4-cyclohexenylene, 1,4-phenylene, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or pyridine-2,5-diyl; L 1 , L 2 , L 3 and L 4 are each independently hydrogen or fluorine, and at least three of them are fluorine; and Z 1 is a single bond, —(CH 2 ) 2 —, —CH═CH—, —C≡C—, —CH 2 O— or —OCH 2 — when ring A 1 is trans-1,4-cyclohexylene, 1,4-cyclohexenylene, tetrahydropyran-2,5-diyl, 1,3-dioxane-2,5-diyl, pyrimidine-2,5-diyl or pyridine-2,5-diyl, and Z 1 is —(CH 2 ) 2 —, —CH═CH—, —C≡C—, —CH 2 O— or —OCH 2 -when ring A 1 is 1,4-phenylene.