US Patent 7396486 Polymerizable mixtures

A mixture which is polymerizable to polymers exhibiting a high optical anisotropy which is stable during polymerization. The mixture contains a first monomer or (and/or) oligomer having two or more polymerizable functional groups and optionally a mesogenic group; a second monomer or oligomer bearing at least one mesogenic group having an aromatic double ring structure and only one polymerizable group; and from 1 to 50% by weight of a monomer non-polymerizable with the first or second monomer, but which also contains a mesogenic group having an aromatic double ring structure.