Patent ID: 7736707

Claim:
A birefringent film comprising a lyotropic liquid crystalline polycyclic compound represented by the following general formula (II): wherein, A 1 , A 2 , X 1 , and X 2 each independently represent —COOM, —SO 3 M, —PO 3 M, —OH, or —NH 2 ; Y 1 , and Y 2 each independently represent a halogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, —OCOCH 3 , —NHCOCH 3 , —NO 2 , —CF 3 , —CN, —OCN, —SCN, —COOM, or —CONH 2 ; M represents a counter ion; Z represents a covalent bond, —O(C 2 H 4 O) 1-4 —, —O—, —CO—O—(CH 2 ) 1-4 —O—CO—, —CO—NH—(CH 2 ) 1-4 —NH—CO—, —NH—CO—(CH 2 ) 1-4 —CO—NH—, or an alkyl chain having 1 to 4 carbon atoms; k1 and k2 are each independently an integer of 0 to 3; m1 and m2 are independently 0 or 1; n1 and n2 are independently an integer of 1 to 4.