A display device comprising: a light source device comprising: a first light source ; a second light source ; a light guide plate, LGP , configured to guide light incident from at least one of the first light source and the second light source; an optical film configured to form a distribution of directional light by controlling a progress path of light output from the LGP; and a controller configured to control activation of at least one of the first light source and the second light source; the display device furthermore comprising: a three-dimensional optical element configured to form a 3D light distribution based on the directional light; and a display panel configured to pass through light from the light source device to output an image based on the distribution of directional light; characterized in that when the first light source alone is activated, a distribution of first directional light is formed by the LGP and the optical film, and a 3D image toward a first direction is formed based on the distribution of the first directional light and the 3D optical element, and wherein, when the second light source alone is activated, a distribution of second directional light is formed by the LGP and the optical film, and a 3D image toward a second direction is formed based on the distribution of the second directional light and the 3D optical element; wherein the controller is configured to activate the first light source and the second light source together to form a distribution of third directional light. a light source device comprising: a first light source ; a second light source ; a light guide plate, LGP , configured to guide light incident from at least one of the first light source and the second light source; an optical film configured to form a distribution of directional light by controlling a progress path of light output from the LGP; and a controller configured to control activation of at least one of the first light source and the second light source; a first light source ; a second light source ; a light guide plate, LGP , configured to guide light incident from at least one of the first light source and the second light source; an optical film configured to form a distribution of directional light by controlling a progress path of light output from the LGP; and a controller configured to control activation of at least one of the first light source and the second light source; the display device furthermore comprising: a three-dimensional optical element configured to form a 3D light distribution based on the directional light; and a display panel configured to pass through light from the light source device to output an image based on the distribution of directional light; a three-dimensional optical element configured to form a 3D light distribution based on the directional light; and a display panel configured to pass through light from the light source device to output an image based on the distribution of directional light; characterized in that when the first light source alone is activated, a distribution of first directional light is formed by the LGP and the optical film, and a 3D image toward a first direction is formed based on the distribution of the first directional light and the 3D optical element, and wherein, when the second light source alone is activated, a distribution of second directional light is formed by the LGP and the optical film, and a 3D image toward a second direction is formed based on the distribution of the second directional light and the 3D optical element; wherein the controller is configured to activate the first light source and the second light source together to form a distribution of third directional light. <EOS>