Patent ID: 7713438

Claim:
A liquid crystal composition exhibiting a Twisted Grain Boundary Smectic A (TGBA) phase at room temperature, comprising at least one cholesteric liquid crystal composition and at least one first nematic liquid crystal compound or composition, wherein the cholesteric liquid crystal composition comprises at least one second nematic liquid crystal compound or composition and at least one chiral reagent, and wherein the first nematic liquid crystal compound is a compound represented by the following Formula (I): T 1 -((D 1 ) e -(L 1 ) f ) m -(D 2 ) k -T 2 Formula (I); wherein D 1 and D 2 each independently represent an arylene group, a heteroarylene group or a divalent alicyclic hydrocarbon group; L 1 represents an azomethine group; T 1 represents an alkvl group or an alkoxy group; T 2 represents a cyano group, a halogen atom, a nitro group, a perfluoroalkoxy group or a perfluoroalkyl group; and e, f, m and k satisfy one of the following: e=1, f=1, m=2, k=1; (i) e=2, f=1, m=1, k=1; (ii) e=2, f=2, m=1, k=1; (iii) e=1, f=1, m=1, k=2; or (iv) e=1, f=2, m=1, k=2; and (v) wherein a ratio (A:B) of the second nematic liquid crystal compound or composition (A) to the chiral reagent (B) is from 85 mol %:15 mol % to 99.9 mol %:0.1 mol %.