A display device includes display units arranged in an array and a light guide unit. Each display unit includes a display panel including a display surface configured for displaying an image, and a frame located adjacent to edges of the display surface. The light guide unit includes a lower light guide and an upper light guide. The lower light guide is located above the display units, and includes first gratings. Each first grating corresponds to a side of one of the display unit and is configured for refracting light emitted from the display surface towards the corresponding side of the display unit. The upper light guide is located above the lower light guide and includes second gratings. Each second grating corresponds to one of the first gratings and is configured for reversely refracting light transmitted through the first grating towards a center of the display unit.