The invention relates to a broadband reflective polarizer that comprises a layer of a polymerized mesogenic material exhibiting a helically twisted molecular structure with planar alignment, said reflective polarizer being obtainable by a process wherein a mixture of a chiral polymerizable mesogenic material comprisinga) at least one achiral polymerizable mesogenic compound,b) at least one chiral compound that can in addition be polymerizable and/or mesogenic,c) a polymerization initiator,is coated on a substrate or between two substrates in form of a layer, aligned in a planar orientation so that the axis of the molecular helix extends transversely to the layer, and polymerized by exposure to heat or actinic radiation, and optionally the substrates are removed from the polymerized material, characterized in that said polymerizable material is coated and polymerized between two different substrates, and/or at least one of said substrates comprises a barrier layer on the surface adjacent to the layer of said polymerizable material, to a process of preparing such a broadband reflective polarizer and to a liquid crystal display comprising such a broadband reflective polarizer