Autostereoscopic display apparatus

An autostereoscopic display apparatus includes a spatial light modulator in which alignment features such as bumps or protrusions (104, fig. 11 a) provide radially symmetric alignment of the molecules of the liquid crystal (fig. 12). A parallax element 172 is arranged over the spatial light modulator to direct light from the pixels 210 into different viewing windows (fig. 15). The apertures of the pixels 214, 216 are shaped such that, for each individual row of pixels, a notional line parallel to the geometric axes of the parallax elements (64, fig. 10a) has a total length of intersection with the pixels of the row, weighted for the intensity of light modulated by the alignment features, which is the same for all positions of the notional line, which improves angular intensity uniformity (AIU). The pixels may each include plural apertures, wherein the alignment features of the apertures of each individual pixel are offset from one another in a direction perpendicular to said geometric axes, which improves angular contrast uniformity (ACU). Each aperture may incorporate a compensation feature 220 that compensates for the losses associated with an alignment feature used for aligning radially symmetric liquid crystals.