A display device comprising: a spatial light modulator arranged to output light along an output direction; a display polariser arranged on a side of the spatial light modulator; an additional polariser arranged on the same side of the spatial light modulator as the display polariser (218, 210), the display polariser (218, 210) and the additional polariser being arranged to pass respective linearly polarised polarisation components; and first and second quarter-wave plates (296A, 296B) arranged between the additional polariser and the display polariser (218, 210), the first quarter-wave plate being arranged on the input side of the second quarter-wave plate and being arranged to convert a linearly polarised polarisation state passed by the one of the display polariser (218, 210) and the additional polariser on the input side thereof into a circularly polarised polarisation state, and the second quarter-wave plate on the output side being arranged to convert a circularly polarised polarisation state that is incident thereon into a linearly polarised polarisation state that is passed by the other of the display polariser (218, 210) and the additional polariser on the output side thereof; and at least one retarder arranged between the pair of quarter-wave plates (296A, 296B), wherein the at least one retarder comprises a liquid crystal retarder comprising a layer of liquid crystal material, and the first and second quarter-wave plates (296A, 296B) and the at least one retarder are arranged to introduce phase shifts to polarisation components of light passed by the one of the display polariser (218, 210) and the additional polariser on the input side of the at least one retarder that causes reduction of the luminance of light passed by the one of the other one of the display polariser (218, 210) and the additional polariser along axes that are inclined to the optical axis, characterised in that the liquid crystal retarder has a total retardance for light of a wavelength of 550nm that is within 10% different of a value R in nanometres that is given by the formula R = − 0.02947 * θ ∧ 3 + 5.81385 * θ ∧ 2 − 397.950 * θ + 10090 where θ is the lateral angle of the inclined axis at which a maximum reduction of luminance occurs for inclined axes having an elevation angle of 0 degrees. a spatial light modulator arranged to output light along an output direction; a display polariser arranged on a side of the spatial light modulator; an additional polariser arranged on the same side of the spatial light modulator as the display polariser (218, 210), the display polariser (218, 210) and the additional polariser being arranged to pass respective linearly polarised polarisation components; and first and second quarter-wave plates (296A, 296B) arranged between the additional polariser and the display polariser (218, 210), the first quarter-wave plate being arranged on the input side of the second quarter-wave plate and being arranged to convert a linearly polarised polarisation state passed by the one of the display polariser (218, 210) and the additional polariser on the input side thereof into a circularly polarised polarisation state, and the second quarter-wave plate on the output side being arranged to convert a circularly polarised polarisation state that is incident thereon into a linearly polarised polarisation state that is passed by the other of the display polariser (218, 210) and the additional polariser on the output side thereof; and at least one retarder arranged between the pair of quarter-wave plates (296A, 296B), wherein the at least one retarder comprises a liquid crystal retarder comprising a layer of liquid crystal material, and the first and second quarter-wave plates (296A, 296B) and the at least one retarder are arranged to introduce phase shifts to polarisation components of light passed by the one of the display polariser (218, 210) and the additional polariser on the input side of the at least one retarder that causes reduction of the luminance of light passed by the one of the other one of the display polariser (218, 210) and the additional polariser along axes that are inclined to the optical axis, characterised in that the liquid crystal retarder has a total retardance for light of a wavelength of 550nm that is within 10% different of a value R in nanometres that is given by the formula R = − 0.02947 * θ ∧ 3 + 5.81385 * θ ∧ 2 − 397.950 * θ + 10090 where θ is the lateral angle of the inclined axis at which a maximum reduction of luminance occurs for inclined axes having an elevation angle of 0 degrees.