A switchable autostereoscopic display device includes a display panel having an array of display pixels for producing a display, and a lens arrangement for directing the output from different pixels to different spatial positions to enable a stereoscopic image to be viewed. The lens arrangement is in a plane parallel to the display panel and includes an electrically switchable LC layer which defines a lens pattern or a lens replica pattern. The LC alignment of the LC layer is electrically switchable such that the lens arrangement is switchable between 2D and 3D modes. In the 2D mode, the LC alignment is in a first direction substantially within the plane of the lens arrangement; and in the 3D mode, the LC alignment is in a second, perpendicular direction also substantially within the plane of the lens arrangement. The light output of the display panel is polarized in the second direction.