Patent ID: 7951305

Claim:
A compound represented by general formula (a): wherein in general formula (a), Ra and Rb are each independently hydrogen, halogen or alkyl having approximately 1 to approximately 9 carbons, provided that in the alkyl, —CH 2 — may be replaced by —O—, —CH 2 CH 2 — may be replaced by —CH═CH—, and hydrogen may be replaced by halogen; rings A 1 , A 2 , A 3 and A 4 are each independently trans-1,4-cyclohexylene or 1,4-phenylene, provided that in these rings, hydrogen may be replaced by halogen, and in the case where the ring is trans-1,4-cyclohexylene, —CH 2 — may be replaced by —O— or —CH═CH—, and in the case where the ring is 1,4-phenylene, —CH═ may be replaced by —N═; Z 1 , Z 2 , Z 3 and Z 4 are each independently a single bond or alkylene having 1 to 4 carbons, provided that in the alkylene, arbitrary —CH 2 — may be replaced by —O— or —CO—, arbitrary —CH 2 CH 2 — may be replaced by —CH═CH— or —C≡C—, and arbitrary hydrogen may be replaced by halogen; l, m, n and o are each independently 0 or 1; and ring L is ring L1: wherein in ring L1, when X is hydrogen, Y is —CF 2 —; and when X is halogen, Y is —C(═O)— or —CF 2 —.