A directional display device comprising: a waveguide having an input end; an array of light sources disposed at different input positions in a lateral direction across the input end of the waveguide, the waveguide further comprising first and second, opposed guide surfaces (6, 8) for guiding light along the waveguide, the first guide surface being arranged to guide light by total internal reflection, the second guide surface comprising light extraction features oriented to reflect light guided through the waveguide in directions allowing exit through the first guide surface as output light, the second guide surface further comprising intermediate regions between the light extraction features that are arranged to direct light through the waveguide without extracting it, the waveguide being arranged to direct input light from different light sources through the first guide surface as the output light into respective optical windows in output directions distributed in the lateral direction in dependence on the input positions; a transmissive spatial light modulator arranged to receive the output light from the first guide surface and arranged to modulate a first polarisation component of the output light having a first polarisation; a reflective polariser disposed between the first guide surface of the waveguide and the spatial light modulator and arranged to transmit the first polarisation component and to reflect a second polarisation component of the output light having a polarisation orthogonal to the first polarisation 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 (203, 205) inclined in opposite senses in a plane that is oriented around the normal to spatial light modulator so that the rear reflector converts the polarisation of the rejected light supplied back to spatial light modulator into the polarisation of the first polarisation component on reflection from a pair of corner facets (203, 205). a waveguide having an input end; an array of light sources disposed at different input positions in a lateral direction across the input end of the waveguide, the waveguide further comprising first and second, opposed guide surfaces (6, 8) for guiding light along the waveguide, the first guide surface being arranged to guide light by total internal reflection, the second guide surface comprising light extraction features oriented to reflect light guided through the waveguide in directions allowing exit through the first guide surface as output light, the second guide surface further comprising intermediate regions between the light extraction features that are arranged to direct light through the waveguide without extracting it, the waveguide being arranged to direct input light from different light sources through the first guide surface as the output light into respective optical windows in output directions distributed in the lateral direction in dependence on the input positions; a transmissive spatial light modulator arranged to receive the output light from the first guide surface and arranged to modulate a first polarisation component of the output light having a first polarisation; a reflective polariser disposed between the first guide surface of the waveguide and the spatial light modulator and arranged to transmit the first polarisation component and to reflect a second polarisation component of the output light having a polarisation orthogonal to the first polarisation 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 (203, 205) inclined in opposite senses in a plane that is oriented around the normal to spatial light modulator so that the rear reflector converts the polarisation of the rejected light supplied back to spatial light modulator into the polarisation of the first polarisation component on reflection from a pair of corner facets (203, 205).