Patent ID: 7695777

Claim:
A liquid crystal compound comprising a compound selected from a group of compounds represented by formula (a): wherein Ra and Rb are each independently linear alkyl having 1 to 10 carbons, linear alkoxy having 1 to 9 carbons, linear alkoxyalkyl having 2 to 9 carbons, linear alkenyl having 2 to 10 carbons, linear alkenyloxy having 2 to 9 carbons; ring A 1 , ring A 2 and ring A 3 are each independently trans-1,4-cyclohexylene or 1,4-phenylene; Z 1 , Z 2 and Z 3 are each independently a single bond or —(CH 2 ) 2 —; l, m and n are each independently 0, 1 or 2, provided that l+m+n is 0, 1, 2 or 3; one of X 1 and X 2 is fluorine, and the other is chlorine; Q is and atoms comprising the compound each may be an isotope thereof.