Patent ID: 8064035

Claim:
A polarizer comprising a polarization grating arranged to diffract an incident light beam into a first diffracted light beam of a first polarization and a first direction and a second diffracted light beam of a second polarization and a second direction, a means for converting the polarization of said second beam into the polarization of said first beam, and a means for collimating said first and said second light beams, wherein the polarization grating comprising a polarization sensitive photo-alignment layer and at least a first and a second liquid crystal composition arranged on said alignment layer, wherein an anisotropic alignment pattern corresponding to a polarization hologram is arranged in said photo-alignment layer and wherein said first liquid crystal composition is arranged on and aligned by said alignment layer and at least partly polymerized, and wherein said second liquid crystal composition is arranged on and aligned by said first liquid crystal composition, and wherein both liquid crystal compositions have a layer thickness d which is determined by the following formula d≦d max =Λ/2 where d is the thickness of the layer and Λ is the pitch of the polarization grating.