A directional display device comprising: a waveguide comprising first and second, opposed guide surfaces (6, 8) for guiding light along the waveguide and an input surface extending between the first and second guide surfaces (6, 8); an array of light sources disposed at different input positions along the input surface of the waveguide and arranged to input input light into the waveguide, the waveguide further comprising a reflective end for reflecting the input light from the light sources back along the waveguide, the second guide surface being arranged to deflect the reflected input light through the first guide surface as output light, and the waveguide being arranged to image the light sources in a lateral direction so that the output light from the light sources is directed into respective optical windows in output directions that are distributed in dependence on the input positions of the light sources; a transmissive spatial light modulator arranged to receive the output light and arranged to modulate a first polarization component of the output light having a first polarization state; a reflective polarizer disposed between the first guide surface of the waveguide and the spatial light modulator and arranged to transmit the first polarization component and to reflect a second polarization component of the output light having a second polarization state orthogonal to the first polarization state as rejected light; and a rear reflector disposed behind the second guide surface arranged to reflect the rejected light for supply back to the spatial light modulator, the rear reflector comprising a linear array of pairs of reflective corner facets (303, 305) extending in a predetermined direction perpendicular to the normal to the spatial light modulator so that the rear reflector converts the polarization state of the rejected light that has a double reflection from a pair of corner facets (303, 305) into an orthogonal polarization state; one or more correction retarders disposed between the reflective polarizer and the rear reflector, characterised in that the one or more correction retarders comprising birefringent material having a slow axis extending in a direction perpendicular to the predetermined direction, the one or more correction retarders being arranged to provide a net effect of relatively shifting the phase of the first and second polarization components incident thereon in a direction normal to the spatial light modulator by half a wavelength. a waveguide comprising first and second, opposed guide surfaces (6, 8) for guiding light along the waveguide and an input surface extending between the first and second guide surfaces (6, 8); an array of light sources disposed at different input positions along the input surface of the waveguide and arranged to input input light into the waveguide, the waveguide further comprising a reflective end for reflecting the input light from the light sources back along the waveguide, the second guide surface being arranged to deflect the reflected input light through the first guide surface as output light, and the waveguide being arranged to image the light sources in a lateral direction so that the output light from the light sources is directed into respective optical windows in output directions that are distributed in dependence on the input positions of the light sources; a transmissive spatial light modulator arranged to receive the output light and arranged to modulate a first polarization component of the output light having a first polarization state; a reflective polarizer disposed between the first guide surface of the waveguide and the spatial light modulator and arranged to transmit the first polarization component and to reflect a second polarization component of the output light having a second polarization state orthogonal to the first polarization state as rejected light; and a rear reflector disposed behind the second guide surface arranged to reflect the rejected light for supply back to the spatial light modulator, the rear reflector comprising a linear array of pairs of reflective corner facets (303, 305) extending in a predetermined direction perpendicular to the normal to the spatial light modulator so that the rear reflector converts the polarization state of the rejected light that has a double reflection from a pair of corner facets (303, 305) into an orthogonal polarization state; one or more correction retarders disposed between the reflective polarizer and the rear reflector, characterised in that the one or more correction retarders comprising birefringent material having a slow axis extending in a direction perpendicular to the predetermined direction, the one or more correction retarders being arranged to provide a net effect of relatively shifting the phase of the first and second polarization components incident thereon in a direction normal to the spatial light modulator by half a wavelength.