Patent ID: 6899929

Claim:
Polymer layers comprising an anisotropic polymer layer exhibiting a tilted structure with an optical axis having a tilt angle θ relative to the plane of the layer greater than zero, obtained by polymerizing a polymerizable mesogenic material comprising at least one compound of the formula: P-(Sp-X) n -MG-R I wherein P is a polymenzable group, Sp is a spacer group having 1 to 20 C atoms, X is a group of —O—, —S—, —CO—, —COO—, —OCO—, —OCOO— or a single bond, n is 0 or 1, MG is a mesogenic or mesogenicity supporting group, and R is an alkyl radical with up to 25 C atoms optionally unsubstituted, mono- or polysubstituted by halogen or CN, optionally one or more non-adjacent CH 2 groups are replaced, independently, by —O—, —S—, —NH—, —N(CH 3 )—, —CO—, —COO—, —OCO—, —OCO—O—, —S—CO—, —CO—S— or —C≡C— where oxygen atoms are not linked directly to one another, or R is halogen, cyano or, independently, P-(Sp-X) n — as defined in formula I, wherein the polymerizable mesogenic material comprises at least 95% by weight of polymerizable compounds, and the tilt angle θ in each of said layers varies continuously in a direction normal to the layer, starting from a minimum value θ min of 0-20 degrees the side of the layer facing the other layer or, if present, the common substrate, and ranging to a maximum value θ max of 20-90 degrees on the opposite side of the layer.