DEVICE FOR THE ELIMINATION OF THE ZERO ORDER BEAM EMERGING FROM A HOLOGRAM ILLUMINATED IN POLARIZED LIGHT

摘要

Device for elimination of the zero order beam emerging from holograms illuminated in polarized light includes a birefringent plate (5) illuminated by both said zero order beam (3) and by a diffracted beam (4) emerging from the hologram (2). The plate is arranged and sized such that one of the beams (3, 4) emerges from the plate with its plane of polarization not appreciably rotated and such that the other of said beams emerges with its plane of polarization rotated by 90 DEG . The device further includes a polarizer (9) illuminated by the beams (3', 4') emergent from the birefringent plate (5), the polarizer having its plane of maximum transmittance parallel to the plane of polarization of the diffracted beam emerging from the birefringent plate as beam (4'). The device finds industrial applicability in the optical systems of video image projectors employing active matrix liquid crystal cells.