Patent ID: 8119026

Claim:
A birefringent layer with R 450 /R 550 <1, wherein R 450 is the optical on-axis retardation at a wavelength of 450 nm and R 550 is the optical on-axis retardation at a wavelength of 550 nm, said layer comprising an LC medium that comprises one or more non-polymerizable compounds of formula I as a guest component wherein U 1 and U 2 are independently of each other selected from the group consisting of including their mirror images, wherein U 1 and U 2 are each bonded to the group —(B) q — via an axial bond, and in which one or two non-adjacent ring CH 2 groups are optionally replaced by O and/or S, and U 1 and U 2 are optionally substituted by one or more groups L, L is, in case of multiple occurrence independently of one another, F, Cl, Br, I, —CN, —NO 2 , —NCO, —NCS, —OCN, —SCN, —O(═O)NR 0 R 00 , —C(═O)X, —C(═O)OR 0 , —C(═O)R 0 , —NR 0 R 00 , —OH, —SF 5 , optionally substituted silyl, aryl with 1 to 12 C atoms, or straight chain or branched alkyl, alkoxy, alkylcarbonyl, alkoxycarbonyl, alkylcarbonyloxy or alkoxycarbonyloxy with 1 to 12 C atoms, wherein one or more H atoms are optionally replaced by F or Cl, X is halogen, Q 1 and Q 2 are independently of each other CH or SiH, Q 3 is C or Si, B is in each occurrence independently of one another —C≡C—, —CY 1 ═CY 2 — or an optionally substituted aromatic or heteroaromatic group, Y 1 and Y 2 are independently of each other H, F, Cl, CN or R 0 , g is an integer from 1 to 10, A 1 , A 2 , A 3 and A 4 are independently of each other selected from the group consisting of non-aromatic carbocylic groups, heterocyclic groups, aromatic groups and heteroaromatic groups, which are optionally substituted by one or more L, and wherein each of -(A 1 -Z 1 ) m —U 1 —(Z 2 -A 2 ) n - and -(A 3 -Z 3 ) o —U 2 —(Z 4 -A 4 ) p - does not contain more aromatic groups than non-aromatic groups, Z 1 , Z 2 Z 3 and Z 4 are independently of each other —O—, —S—, —CO—, —COO—, —OCO—, —O—COO—, —CO—NR 0 —, —NR 0 —CO—, —NR 0 —CO—NR 0 —, —OCH 2 —, —CH 2 O— —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —CH 2 CH 2 —, —(CH 2 ) 3 —, —)CH 2 ) 4 —, —CF 2 CH 2 —, —CH 2 CF 2 —, —CF 2 CF 2 —, —CH═CH—, —CY 1 ═CY 2 —, —CH═N—, —N═CH—, —N═N—, —CH═CR 0 —, —CH═CH—COO—, —OCO—CH═CH—, CR 0 R 00 or a single bond, R 0 and R 00 are independently of each other H or alkyl with 1 to 12 C-atoms, m and n are independently of each other 0, 1, 2, 3 or 4, o and p are independently of each other 0, 1, 2, 3 or 4, and R 1 , R 2 , R 3 , R 4 and R 5 are independently of each other identical or different groups and are H, halogen, —CN, —NC, —NCO, —NCS, —OCN, —SCN, —C(═O)NR 0 R 00 , —C(═O)X 0 —C(═O)R 0 , —NH 2 , —NR 0 R 00 , —SH, —SR 0 , —SO 3 H, —SO 2 R 0 , —OH, —NO 2 , —CF 3 —SF 5 , optionally substituted silyl, or carbyl or hydrocarbyl with 1 to 40 C atoms that is optionally substituted and optionally comprises one or more hetero atoms, and wherein one or more H atoms are optionally replaced by D atoms, and further comprising one or more mesogenic or liquid crystalline compounds as a host component.